Creative photoshop cs4 digital illustration and art techniques free

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Creative photoshop cs4 digital illustration and art techniques free

An easy 5 stars, great work. This is a crucial step especially for читать далее material with high defect densities. You can create any subject you like, but try to make it a nice, sharp piece in solid black and solid white. The Al Si aluminum silicon system. In addition to editing advantages, layers also allow you to easily and gently build up brush strokes within your fref, resulting in a beautiful and authentic appearance.

Title – Creative Photoshop CS4 [Book] – Supported File Formats

In addition to four brand new chapters on real world projects, this new edition of award-winning digital artist Derek Lea’s bestselling Creative Photoshop contains several brand new features such as “What you’ll learn in this chapter” summaries, so you can quickly find projects using the specific tools you’d like to focus on, and supplementary information at the end of each chapter, containing useful resources and additional gallery images to provide further study and inspiration.

Project files for each chapter are also available for download for you to work with as you work through the book. Product Identifiers Publisher. Product Key Features Author. Publication Name. Publication Year. Number of Pages. Dimensions Item Length. Item Height. Item Width. Item Weight. I really can’t recommend this book enough. The tutorials are easy to understand even when dealing with advanced techniques. It could be a bit much if you are brand new to Photoshop but I doubt it.

I don’t think anyone looking into purchasing a book of this type would be at all disappointed. There are other tutorial books out there but this one has subjects and artwork that are truly engrossing. Not only are the tutorial format and content superb but the author offers an online community that can be accessed through his personal site. Here you can ask for help on problem areas from other readers and often the author himself and also post your own work that the lessons have hopefully helped you to create.

An easy 5 stars, great work. I purchased this book on a whim and was pleasantly surprised by the quality of its content. Lea takes readers step by step through simple and very complex design techniques.

His instructions are easy to follow and, unlike many other Photoshop books I have picked up, just as easy to apply to other projects! Having access to the author through the reader forum on the book website makes this an even more useful tool.

Any tips that might seem vague are easily explained by the man who wrote the book – and other readers that have overcome similar problems. I have worked through several books on Photoshop, but this has been the best by far! I have been a fan of Derek Leas work for a number of years since first discovering his tutorials in Computer Arts magazine. I often emailed Derek asking him if he was going to write a book on advanced digital imaging techniques. Derek finally took the challenge of writing a book and to say that the wait was worthwhile is an under statement!

If you are a keen digital artist hungry for new techniques to apply to your work this is the book for you. I cannot recommend this book highly enough!!! This is one of very few Photoshop books that focuses on the creation of digital art, rather than the techniques required for certain standard tricks and effects Congratulations to Derek Lea, and needless to say, highly recommended!

Use the Path Selection tool to select one of the wrinkle shape components that you created at the left. Then, hold down the Shift key and click on the other wrinkle shape components at the left to select them as well.

Custom shapes When you have spent some time creating a shape of your own with the Pen tool or by editing a preset shape, you may wish to save it for use later on. This will allow you to name the shape and save it. The next time you select the Custom Shape tool, your custom shape will appear in the list of presets available in the Tool Options bar. Reposition them if necessary with the Path Selection tool.

Your top layer is currently targeted in the Layers palette. Hold down the Shift key and click on the shape layer directly above the background layer. This targets the new layer, the top layer, and all layers and groups in-between.

Navigate to another area of the canvas. Draw an ear at the left of his head. Use the Path Selection tool to position it exactly where you want it on the layer. Now, double-click your shape layer thumbnail in the Layers palette. This will launch the picker. Choose a new, light green fill color for your layer and click OK.

You can change the fill color of any shape layer at any point by double-clicking the layer thumbnail. As you can see now, there are numerous ways to specify and edit the fill colors of your shape layers. Changing the fill color 17 Add a stroke effect to this layer. Use a darker green color, a generous thickness, and position it outside so that it surrounds the exterior of the shape components. Select the rounded rectangle shape tool in the Tool Options bar.

Set the radius very high. Then click and drag to create a tooth shape on a new shape layer. Change the fill color of the layer to light yellow. This layer automatically has the previous stroke effect applied to it. Double-click the effect in the Layers palette to edit it, reducing the size of the stroke. Another way to quickly change the fill color of a shape layer is to start by targeting a shape layer in the Layers palette.

Next, choose a foreground color from the picker. Repeat the process again until there are three teeth on this layer. Target all three shape components and then click on the Align Vertical Centers button in the Tool Options bar to align the shape components. Use the Pen tool to create an antenna shape on the left side of the head, on a new, different colored shape layer.

Ensure the Link button is disabled in the Tool Options bar, and set the style back to none in the style picker. Build half of the face Put your new shape layer skills to good use as you create all of the details for the left side of the face on a series of shape layers. Drag the corner points to resize, then click and drag outside of the box to rotate.

Press Enter to apply the transformation. Then repeat the process again, creating a smaller, black ellipse shape layer. Create a white ellipse shape layer over top of the black ellipse and reduce the layer opacity. Target all of these layers, including the antenna layer, and add them to a new group.

Use the Move tool or the arrow keys on the keyboard to adjust the positioning on the canvas if necessary. Target all of the layers and groups that make up the alien character in the Layers palette and add them to a new group. Use the Pen tool to click and drag, creating a closed object that resembles tentacles on a new shape layer. Specify a green fill color and then switch to the Ellipse tool.

Click and drag to create a large ellipse that overlaps the top of the tentacles shape on the same layer, creating a strange octopus body. As always, pressing Enter will apply the transformation. All of the methods are the same as before. Examine the downloaded files At this point in the chapter, you should have the three main characters completed and organized into groups. Everything you need to know to effectively create the characters has been outlined on the previous pages.

However, if you still find yourself confused by a small detail or are scratching your head over something, have a look at the sample files included in the archive you downloaded.

The files are named sample Each file contains a single character group and you can inspect the shape layers and components in detail within these files.

Here, new shape layers were added to the octopus group as well as the alien group. Each new layer was placed in the appropriate group, ensuring that the Layers palette remained organized. Use FreeTransform to rotate, resize, and move it to another location on the canvas.

Double-click individual layers within the group and change their fill colors. Delete the shape layers that make up his mouth by dragging them into the trash in the Layers palette. Then add a new shape layer that contains a small black ellipse to the group, creating a new mouth with a different facial expression. Use this method to create a number of different octopus groups on the canvas. Alter colors and shape layers as you see fit. Move them up and down within the Layers palette so that some characters are overlapping others.

Try varying blending modes of your duplicate groups here and there. Also experiment with reduced opacity to make some of them less prominent. Move it to another location and use Free-Transform to resize and rotate the group. Repeat this process over and over, adding a number of blue creatures to the scene. Like you did previously with the octopus, move duplicate groups up and down within the Layers palette altering the blending modes and opacity settings of entire groups as you go.

Hiding versus deleting When you are creating duplicate character groups and wish to remove layers from the group, disable them rather than delete them. You can disable the visibility of any layers you wish to hide, and when you transform an entire group, these hidden layers will be transformed alongside the rest. This is a better option than deleting as it gives you the option of making the layers visible again if you change your mind later on.

Alter blending modes, opacity, and try disabling the visibility of some layers. Try combining some of your duplicates into groups as well. Here, this creature was created by adding a blue creature group and an octopus group into a new group. The blue creature was positioned on top of the octopus and the fill color of the octopus layer was changed to match that of the blue creature.

Then, the blending mode of the new group was changed to luminosity. Use the Subtract and Add to Shape Area options freely. Also, have some fun with different blending modes, color fills, and layer opacity settings. Drag all of the new shape layers beneath the character groups in the Layers palette, so that the new shape layers are used to enhance the painted background rather than overlapping the creatures.

Place the new shape layers in a group of their own, just to keep the Layers palette organized. In this case, the creature enhances the background using only its luminosity. It is quite similar stylistically, but the subject is a little different. There is a lot you can do when you begin experimenting with shape layers, groups, blending modes, and underlying textures. It takes a bit of practice, but as you can see here, the results are worth it. All that you need these days is a digital photo, a scanned drawing of your plan, and a little Photoshop know-how.

Photoshop offers all of the tools necessary to add innovative digital graffiti to any photographed scene. Brushes, selections, and layer blending modes are essential Photoshop tools to get the job done.

Above all other features, these are key ingredients in producing convincing graffiti art. These two features give the Brush tool its authentic spray paint feel and allow you to produce convincing spray paint results.

While producing real spray paint art, you get annoying drips littering your masterpiece when you apply too much paint to a single area at once. And rather than creating a digital backdrop for the graffiti art, it is painted directly on top of a photo of a bare wall, using layer blending modes to make it look as if it really belongs there.

A basic understanding of the Brush tool and Layers palette will make this chapter easier for you. It takes practice. It is very important to exercise a little forethought when you set out to do something like this.

Knowing that I was going to be spraying paint digitally, and knowing that I could get that paint to build up naturally, I knew that I wanted it to drip. Now, there is no gravity in Photoshop, so creating dripping paint would have to be done in the real world or carefully faked digitally.

Although this is a common theme that pops up again and again throughout this book, it is very important to mentally prepare yourself for the task at hand. Get everything together and then launch Photoshop. As you work your way through this chapter and get to the dripping paint part, it will become clear that spraying these drips on paper ahead of time was the best and most efficient method to create a realistic effect.

Photoshop Tools, Features, and Functions Airbrush capabilities This feature does not get enabled often. It allows the brush to deposit paint the way a spray can would. There is an endless stream when you hold the button down and the movement of the mouse directly affects how much paint is deposited in a given area. Opacity and flow Using these two Brush tool options together allows you to customize how paint is deposited by your virtual airbrush.

The numbers you enter in these fields will have an immense effect on how natural your sprayed strokes appear. This will act as your background for the image and this file will become the bottom layer of our multilayered working file.

The first thing you notice about the wall is that the darker details are not pronounced enough. Perhaps the original photograph was a little overexposed. To remedy this, drag the background layer onto the Create a New Layer button at the bottom of the Layers palette to duplicate it. Target the duplicate layer and change the blending mode of the layer to linear burn. In either case, reduce the saturation by around 28 in the Adjustments panel to remove color from the underlying layers.

Click OK. All of the files needed to follow along with this chapter and create the featured image are available for download on the accompanying Web site in the project files section. Return to your working file and navigate to the Channels palette. In the Channels palette, click on the Create New Channel button at the bottom of the Channels palette to create an empty alpha channel. Go your own way The black-and-white art here is a very sharp and finely tuned piece of artwork.

However, what makes every graffiti artist unique is his or her style of drawing. Feel free to carefully draw your own black-and-white artwork and substitute it for the one used here. There is no part of the process more appropriate to expressing your individual style than the black-andwhite art stage.

You can create any subject you like, but try to make it a nice, sharp piece in solid black and solid white. This will help to keep the channel clean, resulting in a nice, clearly defined selection border.

Return to the Layers palette and click on the Create a New Layer button to create a layer at the top of the stack within the palette.

Enter a radius setting that softens the edges of your black line work. Softening the edges, combined with the layer blending mode of multiply, is what will give the art on this layer the appearance of being sprayed onto the wall. Be careful not to soften the edges too much, you still want your artwork to look like something. Because you are pasting black art on a white background into an alpha channel, it needs to be inverted first, so that the art is white and the background is black.

Or, you can leave your art in its positive state and double-click your alpha channel in the Channels palette. Then, from within the Channel options, change things so that color indicates selected areas rather than masked areas before you paste your copied art into it. Here, a series of black paint drips were painted on a white piece of paper.

Holding the can in one place while spraying allows you to build up enough paint in that spot so that it begins to run. Black and white were used because these paint drips, after being scanned, are destined to be used to create custom selections within a series of alpha channels. Open up the drips. This is a desktop scan of a group of spray paint drips. Invert the file and then use the Lasso tool to draw a rough selection that contains one entire drip.

Adding a paint drip Paste a copied paint drip into your alpha channel using the visible composite channel to aid with proper positioning. Create a new channel, ensuring that color indicates masked areas the default setting.

Target your new channel and enable the visibility of your CMYK composite channel in the Channels palette. Shift-drag a corner of the bounding box inward to reduce the selection contents. Click and drag within the bounding box to position your drip over a corner area of your black outline art. Keep the visibility of the composite channel enabled to help you position your drips properly and use Free-Transform to adjust size, rotation, and placement.

When you have a number of drips in your channel that sit nicely over appropriate areas of the image, load the channel as a selection. When placing a drip area within the image, try to think of where it would occur realistically. You know that drips traditionally occur because too much paint is applied in a single area at one time. So try to look at areas of the art where a spray can is likely to spend a lot of time. Corners are a perfect place.

Actually, anywhere where two lines meet means that the spray can will deposit more paint in that area. Working along these lines will aid in achieving a realistic result. Next, click on the eye icon to the left of your alpha channel to disable the visibility of that channel, causing the red overlay to disappear. Return to the Layers palette and ensure that the layer containing your black outline art is targeted.

Fill the current selection with black on this layer and deselect. Just open the Tool Preset picker at the far left of the Tool Options bar. Once the picker is open, just click on the Create New Tool Preset button to add your current tool to the list of presets. From that point on, your brush will reside within the preset picker for immediate access. In the Brushes palette, choose one of the soft, round brush tip presets.

Disable shape dynamics because we do not want the actual thickness of the stroke to change. Enable the Airbrush option as well as the Smoothing option. Try painting a few strokes at various areas on the black layer that surround the outline art. The longer you stay in one place with the mouse button down, the more the paint will build up in that area.

Move the mouse quickly while holding down the button to paint a light stroke or move slowly to paint a darker stroke. The faster you move the mouse, the less paint will be deposited in the stroke because the flow cannot keep up with you—just like real-world spray painting. Try creating a stroke very quickly while holding down the mouse button. Then stay completely still at the end of the stroke while continuing to hold down the mouse button. This will cause paint to build up in the area where you are hovering—just like it would if you were using a real spray can.

Also try increasing the brush size and reducing the flow so that it looks as if the spray can was held further away while you were painting on the wall.

Continue painting on this layer until you think the black spray paint effect is complete. Also, if you feel that you need some more drips on this layer, use the methods employed previously to add drips.

Create a new layer and drag it beneath the black outline layer in the Layers palette. Reduce your brush diameter slightly in the Brushes palette. Begin to paint some strokes within areas defined by black outlines on the new layer. Now select a purple color from the picker and continue to paint some purple strokes within the same regions of the artwork on the current layer. Remember to vary flow settings, brush diameter, and the speed at which you paint your strokes to achieve the authentic spray paint effect.

Quickly pressing a number key on the keyboard will set your brush opacity, using a multiple of ten. Or, if you want something precision, simply type the two numbers of your desired opacity.

Holding down Shift while pressing a number key will allow you to adjust the flow instead of the opacity. If you have the Airbrush option enabled, things are reversed. When the Airbrush is enabled, simply pressing a number key changes the flow and holding down the Shift key while you press a number key changes the opacity. Use the current brush settings to paint a series of white strokes on this new layer to create highlights on the shapes inside the black outlines.

Also, increase the diameter of the brush and reduce the flow. Then paint some strokes with these brush settings to create a softer, more gradual highlight effect within the shapes. Use the Lasso to draw a rough selection around a cluster of drips and copy it. Return to the working file, create another alpha channel, and target it in the Channels palette.

Enable visibility of the composite channel again and then paste into your new alpha channel. Position it so that it overlaps an area of opaque white and then press Return to apply the transformation.

Repeat this process to add a few drips to the alpha channel and then generate a selection from it. Target the composite channel and disable the visibility of your new alpha channel. With the current selection active, return to the Layers palette. Target the layer with the white highlights painted onto it.

Specify a white foreground color and fill the active selection with it. Deactivate the selection. Varying paint colors 16 Create a new layer and drag it beneath the white highlight layer in the Layers palette. Greatly reduce the size of your brush so the stroke thickness is similar to that of your thin white highlight strokes. Be certain to paint over some areas enough times so that there are a few solid red blobs of paint on this layer.

Also, increase the brush diameter and reduce the flow setting. With these brush settings, paint some larger, softer strokes here and there on the current layer. Unlike traditional painting, we can change our minds regarding color after the fact when creating graffiti art in Photoshop. Also, you can target a layer in the Layers palette, enable the transparency lock, and then fill the targeted layer with any color you choose.

This will allow you to instantly change the painted areas of the layer while preserving the transparent areas. Paste some selected drips into a new alpha channel. Generate a selection from the channel and fill the selected areas with the same red foreground color on the current layer. Feel free at this point to embellish the image by painting some finer strokes of vibrant color on top of the existing layers on a new layer. Moving quickly deposited less paint, allowing us to see the detail of the wall through the paint in a number of areas.

Even while using the Airbrush option, no matter how long you hold the mouse button down in Photoshop, the paint simply will not drip as it piles up. It is light where the motion was quick and heavy where the tool was stagnant.

First target only the layers that make up the painted graffiti in the image. Group them and then simply drag the group into another image window.

Traditionally, a stencil is made from paper, cardboard, or plastic. Usually the stencil is held tight against a wall or another surface and paint is sprayed onto it. Removing the stencil after painting reveals an instant application of the stencil art on the desired surface.

Ideally, the paint will only touch the surface in areas where holes are present in the stencil. However, part of the signature appearance of stencil graffiti is the overspray effect that occurs around the edges.

The ideal way to do this is to edit the art and then define it as a Custom Brush preset. All that you need to do to add a virtual stencil to an existing scene is choose the Custom preset and click once.

This chapter involves simple use of the Brushes palette. Angle and diameter are about as complicated as it gets. Applying stencil art in Photoshop is indeed as simple as a single click of the mouse, but ensuring that it looks realistic is the direct result of the care you take in preparing your custom brush artwork.

Size, color, and position In addition to authentic-looking brushes, placement and position of the stencil itself is crucial. You really need to think about your underlying image. Simple analysis will aid you in determining rotation via brush angle and the size relationship of your stencil against the background. Do this by choosing textural images that express distress in white areas against black, and combining those images with this blending mode. This file provides the subject matter for our initial piece of stencil art.

Generally, stencil graffiti art provides social commentary or incorporates an activist theme, so a gas mask is certainly an appropriate subject matter here. Project files 2 Now open up the spatter. Select the Move tool and then, while holding down the Shift key, click anywhere on the canvas and drag the image into your mask.

This will add the spatter. This layered file will be the working file for your stencil art from this point on. Reduce the opacity of the new layer so that you can see the mask image beneath it. Use the Polygonal Lasso tool to draw a rough selection that surrounds the gas mask, yet includes a bit of white background as well. Choose a large, soft, round Brush preset. Make your mark Although there is artwork provided on the CD as the subject matter for your stencil art, you can feel free to create your own.

Traditionally, stenciling, as a guerilla art form, has been all about expressing yourself and your opinions. The process remains the same and will work with a variety of subjects. Paint over the dark drips in the lower right; also paint over any sharp edges where the spatter abruptly ends, like the upper left, the upper right, and around the edges of the canvas.

Again, use the Move tool to drag the image into your working file as a new layer. Hold down the Shift key as you drag to ensure proper positioning when the scratches file reaches the destination. In the Layers palette, change the blending mode of your new scratches layer to lighten.

This ensures that only the areas on the current layer that are lighter than areas on the underlying layer appear, creating a scratched paint effect on your black stencil art. Next, target your background layer and select the Magic Wand tool. Add light and dark areas Adding light and dark areas within your stencil art helps to create a genuine weathered look when you apply it to your surface destination.

Leave the tolerance set to 32 and click on a non-white area of the background layer. Click on the Create a New Layer button in the Layers palette. Alter brush opacity and diameter as you paint.

Create a new layer and then paint some faint white areas within the active selection on this layer. Increase the diameter of your brush and use a very low opacity setting. This is a grayscale detail photo of a rusted metal surface.

It is not the subject matter that is appealing in this case, but rather the contrast and interesting divisions between light and dark. Then use the Move tool to drag it into the working file as a new layer. Ensure that you hold down the Shift key as you drag to maintain correct positioning. Recognizing potential This rust texture application is an excellent example of the less than obvious usage of certain images.

When you originally look at the digital photo of the rusted box, you see an intriguing texture, but it is important to look at it with different blending mode applications and Layer stacking options in mind as well.

Try to visualize the lighten and darken usage opportunities of basic texture shots. Examine dark and light areas, and think about how they would affect different types of underlying artwork. Experiment with different scans and photos of texture using different blending modes.

To intensify the rusty texture effect, drag the layer onto the Create a New Layer button at the bottom of the Layers palette to duplicate it. This is a great way to increase the textured effect. Use the same procedure to duplicate your scratches layer and move it too. Now, ensure that you are working in Standard Screen mode so that you can view both the skull file and the gas mask working file at the same time. Number of Pages:. About this product. Product Information If you are a digital artist, illustrator, cartoonist, graphic artist, designer, or serious hobbyist looking for new and interesting ways to use Photoshop, this is the book for you You already know how to use Photoshop as an image editing tool; now, challenge yourself and discover the more artistic aspects of the program with one of the world’s best teachers by your side.

It could be a bit much if you are brand new to Photoshop but I doubt it. I don’t think anyone looking into purchasing a book of this type would be at all disappointed. There are other tutorial books out there but this one has subjects and artwork that are truly engrossing.

Not only are the tutorial format and content superb but the author offers an online community that can be accessed through his personal site. Here you can ask for help on problem areas from other readers and often the author himself and also post your own work that the lessons have hopefully helped you to create. An easy 5 stars, great work. I purchased this book on a whim and was pleasantly surprised by the quality of its content.

Having access to the author through the reader forum on the book website makes this an even more useful tool. Any tips that might seem vague are easily explained by the man who wrote the book – and other readers that have overcome similar problems.

I have worked through several books on Photoshop, but this has been the best by far! I have been a fan of Derek Leas work for a number of years since first discovering his tutorials in Computer Arts magazine.

I often emailed Derek asking him if he was going to write a book on advanced digital imaging techniques. Derek finally took the challenge of writing a book and to say that the wait was worthwhile is an under statement! Meemongkolkiat, V. Investigation of modified screen-printing Al pastes for local back surface field formation.

Mehta, S. PV pulse—technology shares, regional production trends, top suppliers, and the outlook for Melnyk, I. High throughput in-line acidic texturisation and edge isolation: an industrial reality. Metz, A. Industrial high performance crystalline silicon solar cells and modules based on rear surface passivation technology.

Micard, G. Advances in the understanding of phosphorus silicate glass PSG formation for accurate process simulation of phosphorus diffusion. Miyajima, S.

Hydrogenated aluminium oxide films deposited by plasma enhanced chemical vapor deposition for passivation of p-type crystalline silicon. Morita, H. Efficiency improvement of solar cell utilizing plasma-deposited silicon nitride. Mosel, F. Growth of high quality silicon mono ingots by the application of a magnetic cusp field in Cz puller.

Moynihan, M. IPA free texturing of mono-crystalline solar cells. Hydrogenated silicon nitride for regeneration of light induced degradation. Murray, J. The Al Si aluminum silicon system. Alloy Phase Diagr. Nagel, H. Determination of optical constants of semitransparent films and substrates for silicon solar cell applications. Nemet, G. PV learning curves and cost dynamics.

In: Advances in Photovoltaics, , vol. Neuhaus, D. Industrial silicon wafer solar cells. Ohl, R. Light sensitive device. Patent No. Ohl, S. Increased internal quantum efficiency of encapsulated solar cells using two-component silicone as encapsulant material. Panasonic press release April 10, Papet, P.

Pospischil, M. Investigations of thick-film-paste rheology for dispensing applications. Correlations between finger geometry and dispensing paste rheology. Ralph, E. Recent advancements in low cost solar cell processing. Ramspeck, K. Light induced degradation of rear passivated mc-Si solar cells. Rauer, M. Investigation of aluminum-alloyed local contacts for rear surfacepassivated silicon solar cells.

Alloying from screen-printed aluminum pastes containing boron additives. Rein, S. Electrical and thermal properties of the metastable defect in boron-doped Czochralski silicon Cz-Si. Quantitative correlation of the metastable defect in Cz-silicon with different impurities. Richards, B.

Comparison of TiO2 and other dielectric coatings for buried contact solar cells: a review. Richter, A. Aluminium oxide for the surface passivation of high efficiency silicon solar cells.

Reassessment of the limiting efficiency for crystalline silicon solar cells. Review on screen printed metallization on p-type silicon. Energy Procedia 21, 14— Add-on laser tailored selective emitter solar cells. Schmidt, J. Structure and transformation of the metastable boron- and oxygen-related defect center in crystalline silicon.

B 69, Electronic properties of light-induced recombination centres in boron-doped Czochralski silicon. Schneider, A. Comparison of gettering effects during phosphorus diffusion for one-and double-sided emitters. Laser-fired rear contacts for crystalline silicon solar cells. Scanning Nd:YAG laser system for industrially applicable processing in silicon solar cell manufacturing.

Schubert, G. Thick film metallisation of crystalline silicon solar cells—methods, models and applications. Formation and nature of Ag thick film front contacts on crystalline silicon solar cells. Current transport mechanism in printed Ag thick film contacts to an n-type emitter of a crystalline silicon solar cell.

Schubert, M. Impact of impurities from crucible and coating on mc-silicon quality—the example of iron and cobalt. Seibt, M. Gettering processes and the role of extended defects.

Shi, Z. Mass production of the innovative Pluto solar cell technology. Shockley, W. Statistics of the recombinations of holes and electrons. Sinton, R. Contactless determination of current-voltage characteristics and minority carrier lifetimes in semiconductors from quasi-steady-state photoconductance data.

Smith, D. Towards the practical limits of silicon solar cells. Solmi, S. Dopant and carrier concentration in Si in equilibrium with monoclinic SiP precipitates. B 53 12 , — High aspect ratio front contacts by single step dispensing of metal pastes. Steyer, M. A study of various methods for the analysis of the phosphosilicate glass layer.

Szlufcik, J. Lowcost industrial technologies of crystalline silicon solar cells. IEEE 85 5 , — Taguchi, M. Takayama, M. Large area high efficiency multicrystalline silicon solar cells. In: Technical Digest of Int. Tjahjono, B. Application of laser doped contact structure on multicrystalline solar cells. Tobias, I. Crystalline silicon solar cells and modules. In: Luque, A. Trumbore, F.

Solid solubilities of impurity elements in germanium and silicon. Bell Syst. Urrejola, E. Al-Si alloy formation in narrow p-type Si contact areas for rear passivated solar cells. Silicon diffusion in aluminum for rear passivated solar cells. Back-contact solar cells: a review.

Vermang, B. Direct tin-coating of aluminum rear contact by ultrasonic soldering. Wagner, H. Improving the predictive power of modelling the emitter diffusion by fully including the phosphosilicate glass PSG layer. Wang, A. Weizer, V. Photondegradation effects in terrestrial silicon solar cells. Wenham, S. Buried-contact silicon solar cells. Buried contact solar cells.

Australian Patent Wilking, S. Influence of hydrogen on the regeneration of boron-oxygen related defects in crystalline silicon. Influence of hydrogen effusion from hydrogenated silicon nitride layers on the regeneration of boron-oxygen related defects in crystalline silicon.

Influence of bound hydrogen states on BO-regeneration kinetics and consequences for high-speed regeneration processes. C , 2—8. Ximello, N. A new KOH-etch solution to produce a random pyramid texture on monocrystalline silicon at elevated process temperatures and shortened process time. Yoshikawa, T. Solid solubilities and thermodynamic properties of aluminum in solid silicon. Zhao, J. C 41 42 , 87— Zulehner, W. Czochralski growth of silicon.

Growth 65, — Introduction 2. Passivating c-Si Surfaces with a-Si:H 2. Losses in Silicon Heterojunction Solar Cells 4. Industrialization and Commercialization 5. Several key factors explain the success of this technology: Silicon is a well-studied semiconductor with known optoelectronic properties; it is abundant and nontoxic, and the price of multicrystalline silicon has witnessed an unprecedented drop in the last few years, partially because of a temporary production overcapacity, especially in Asia; and silicon solar cell technology has greatly benefited from the accumulated knowledge in semiconductor processing developed by the microelectronics community.

An important strength of the current industrial silicon solar cell technology is its fabrication simplicity. Only a few steps suffice to fabricate a full device, where each step often fulfills several roles. Examples of this are the emitter diffusion process, which simultaneously getters impurities from the bulk of the wafer, and the metal contact firing through the silicon nitride anti-reflection coating, during which bulk hydrogenation of the wafer also occurs.

A drawback of this simplicity is that further improvements in device performance must rely on the increasing sophistication of existing processes, while fundamental shortcomings of the technology are hard to overcome. One such critical limitation is carrier recombination at the electrical contacts. Carrier recombination in silicon is a well-understood phenomenon and its minimization is a key factor in obtaining high-efficiency solar cells.

We make a distinction between intrinsic recombination Auger and band-to-band radiative recombination and deep-defect-mediated recombination Richter et al. This structure should feature perfectly passivated surfaces and contacts. Note that, with perfect contacts, the Voc represents the energetic distance between the quasi-Fermi levels, which themselves express the density of excess charge carriers present in the material as a consequence of shining light on it.

An important reason why the Voc can never equal the bandgap of the absorber—1. Despite this, it is possible to come close to the mV limit in real devices with excellent surface and contact passivation. Surface passivation has also improved: A number of dielectric passivation layers are available that can passivate p-type and n-type surfaces very well.

These include materials like silicon oxides Benick et al. Surface passivation can be accomplished in two fundamentally different ways: Either the surface defect states are removed, or the excess charge carriers are screened from the surface defects by an internal electrical field. The former is known as chemical surface passivation and can be obtained by, e. The latter is known as field-effect passivation and is usually obtained by deposition of a fixed-charge dielectric on the surface under study, thereby repelling minority carriers inside the wafer from the defective surfaces.

Positive-fixed-charge dielectrics repel the positively charged holes inside the semiconductor from the surfaces, and are ideally suited to passivate n-type surfaces. A prime example is silicon nitride, which has been used for the passivation of phosphorus-doped emitters in homojunction technology Lanford and Rand, ; Lauinger et al.

Negative-fixed-charge dielectrics repel negatively charged electrons from the surfaces and are used to passivate p-type surfaces. Here, the most studied dielectric is aluminum oxide, which is a material that received significant attention in the last few years as a potential passivating layer for the rear surface of homojunction solar cells Agostinelli et al.

Silicon nitride layers can be relatively easily integrated into existing c-Si solar cell processing, whereas the successful integration of aluminum oxide layers into industrial solar cells has proven to be more of a challenge. In all cases, contacts are needed to extract carriers from the solar cell. In standard homojunction solar cell technology, where the junction is fabricated by thermal diffusion or ion implantation, these contacts are usually defined by locally opening the dielectric passivating layers and making a direct Ohmic contact between the metal and semiconductor.

Whereas the contact resistances of such contacts can be made low, the minoritycarrier recombination occurring at their surfaces is of significant concern. This issue is fundamentally resolved by silicon heterojunction technology, where a thin, wider-bandgap layer is inserted between the metal contact and the optically active absorber i. Qualitatively, this 76 Christophe Ballif et al.

On the one hand, it should prevent generated carriers from being collected instantaneously, as this will lower the energetic splitting of the quasi-Fermi levels and thus reduce the voltage of the device. On the other hand, the contacts should be sufficiently electronically transparent to guarantee that carriers can be collected at the device terminals before they recombine in the wafer due to intrinsic recombination processes.

In principle, such contacts can be fabricated in several ways. Irrespective of the materials used, passivated contacts should feature excellent chemical surface passivation while also giving charge carriers an incentive to be driven toward either the electron- or the hole-collecting layers. In this chapter, the focus will be on heterojunction solar cells with layers fabricated from thin films of amorphous silicon or related materials.

First, a-Si:H passivates c-Si surfaces very well, with electrical properties that are on par with the best dielectrics available.

The passivation is mostly chemical, principally due to hydrogenation of surface states. Second, such layers can be doped relatively well, either n- or p-type, by adding the appropriate process gasses during deposition. This property enables the fabrication of contacts that are selective for either electron collection when n-type a-Si:H is used , or hole collection when p-type a-Si:H is used. This is of significant utility, as it allows us to not simply make passivating contacts but also to escape the need for a homojunction in the wafer.

As the lateral conductivity of the a-Si:H layers is quite low, transparent electrodes that serve electrical and optical roles are usually applied. Another important reason for the success of such layers is the available knowledge regarding thin-film deposition technology. Whereas silicon homojunction solar cell technology has benefited greatly from developments taking place within microelectronics, silicon heterojunction technology benefits from the flat-panel and thin-film solar cell industries, which have developed planar deposition technology with remarkable uniformity over very large surfaces and with high throughput.

Depositions over areas of several square meters coupled with nanometric precision are commonplace. In , Fuhs et al.

In the early s, a new type of tandem silicon solar cell was reported by Hamakawa et al. As the emitter of the bottom cell was made from a-Si:H as well, this is likely the first solar cell incorporating a silicon heterojunction for the emitter formation Hamakawa et al. This makes the heterojunction concept also particularly attractive to fabricate emitters on substrates that would not withstand the temperatures usually involved in homojunction solar cell fabrication.

This point gave Panasonic Sanyo at the time the motivation to incorporate silicon heterojunctions into their thin-film multicrystalline silicon solar cells in the late s Taguchi et al. These cells were identified to suffer from substantial interface recombination. A first significant advance was made when a thin intrinsic a-Si:H layer was inserted between the doped emitter and wafer to alleviate this issue.

This is the so-called heterojunction with intrinsic thin-layer HIT structure, which increased the efficiency up to From this, it was clear that both electron- and hole-collecting contacts need to be passivated, and both can be fabricated by planar heterojunction technology.

This sustained effort found its culmination in a reported solar cell efficiency of This device featured a Voc of mV, a value approaching the theoretical limit, underlining the particular appeal of this technology. With the interdigitated-back-contact configuration, the same company reduced the current losses at the front of the cell 78 Christophe Ballif et al.

Adapted with permission from De Wolf et al. Panasonic recently reached an efficiency of Recombination at surfaces In a working solar cell, generated carriers are collected at the relevant contacts or they recombine.

Whereas the former process constitutes the external device current, the latter is purely a loss mechanism. Prior to either of these two processes occurring, the generated carriers reside in the material, where they contribute to the voltage of the device.

In open-circuit conditions, obviously no current flows, and thus the Voc is directly linked to carrier recombination processes. Microscopically, in c-Si, bulk recombination is usually caused by deep defects, which originate from impurities or crystal defects. Such recombination is usually described by Shockley—Read—Hall recombination statistics. Deep-defect recombination is also of serious concern at clean silicon surfaces.

The reason for this is the fact that the silicon lattice consists of covalent Si—Si bonds that must be broken at the surface. Depending on the precise surface orientation, each silicon surface atom will feature either one as on the silicon surface or two as on the silicon surface dangling bonds.

These clean surfaces are often not stable and may reconstruct into lower-energy configurations, which could feature, e. The remaining silicon dangling bonds need to be passivated, however. The silicon dangling bond is a so-called amphoteric defect, which implies that it can have three different charge states. In this state, it can give up its electron positively charged state or it can host a second electron negatively charged state.

The ease with which the dangling bond can move between these states, accepting either electrons from the conduction band or holes from the valence band, explains its high recombination activity and the need for surface passivation.

Physics of passivation The microscopic passivation mechanism of c-Si by a-Si:H is most likely closely linked to hydrogenation of surface states, where the hydrogen is supplied from the passivating film. For good passivation, it is necessary that the interface between the two materials be atomically sharp, i. For such films, low-temperature annealing can also improve the passivation properties.

For isothermal annealing, it was found that, irrespective of the precise deposition conditions, the electronic properties always obey stretched-exponential laws over the annealing time De Wolf et al.

Based on this, it could be argued that the passivation is to a significant extent driven by microscopic rearrangement of hydrogen close to the interface.

Comparison with the bulk properties of a-Si:H indicated that the dominant defect responsible for recombination must be the same both in the a-Si:H bulk and at a wafer surface, and that this defect is likely the silicon dangling bond De Wolf et al. Quite generally, the passivation properties of a-Si:H films mimic what occurs in their bulk, which includes effects such as light-induced degradation De Wolf et al. Deposition of high-quality a-Si:H films Since the passivating intrinsic a-Si:H layers are of such importance for the final device, great care has to be taken during their deposition.

The development of such industrial reactors dedicated specifically to silicon heterojunction solar cell technology undoubtedly benefited from the knowledge gained in recent years by the thin-film transistor and thin-film silicon solar cell industries Shah et al. Although the passivation properties of an a-Si:H film can generally be improved by thermal annealing De Wolf et al. It has been reported that device-grade, passivating intrinsic a-Si:H layers are deposited in plasma regimes close to the amorphous-to- micro- crystalline transition Descoeudres et al.

With the aid of plasma diagnostics such as infrared absorption spectroscopy or optical emission spectroscopy, it is indeed found that the best as-deposited a-Si:H passivating films are obtained with low-cp plasmas, which correspond precisely to amorphous regimes close to the crystalline transition Strahm et al.

These regimes can be produced either with SiH4 plasmas highly diluted with H2 Gogolin et al. As stated above, epitaxial growth has to be avoided in order to have high passivation quality. To work in regimes close to the amorphous-to-crystalline transition is therefore not without risk. A possible way to further approach the transition without epitaxial growth on the c-Si surface is the use of H2 plasma treatments, either during Descoeudres et al.

Such treatments have several impacts on the deposited a-Si:H material. Depending on the plasma treatment conditions, one observes a modification of the material structure either increased disorder in the silicon network Descoeudres et al. Although treated a-Si:H films may be more disordered and can contain more recombinative defects than untreated films, the passivation quality of the crystalline substrate is generally greatly improved due to the increased hydrogen content in the film.

Note that H2 plasma treatments before a-Si:H growth, i. More generally, the impact of any plasma species impinging on the bare surface at plasma ignition is, to some extent, detrimental to surface passivation Neitzert et al. This damage created at the very early stage of the plasma deposition process is then partly recovered by the passivating effect of the deposited film itself.

Reproduced with permission from Descoeudres et al. Surface passivation on n- and p-type wafers Although p-type c-Si is the standard material for diffused-junction solar cells and therefore largely dominates current industrial photovoltaics production, n-type monocrystalline silicon appears to be the best candidate for highefficiency solar cells and is foreseen to increase its share in c-Si photovoltaics production in the coming years International Technology Roadmap for Photovoltaics, Moreover, Czochralski CZ n-type wafers do not suffer from light-induced degradation, as is the case for CZ p-type wafers when a boron—oxygen or boron—iron complex is present Lagowski et al.

Therefore, considering only the basic bulk properties of c-Si wafers, n-type material is better suited to reach high conversion efficiencies.

Regarding surface passivation with a-Si:H, fundamental differences exist between n- and p-type wafers. As with bulk defects, the capture cross sections of surface defects, i. The same phenomenon occurs for surface defects with thermally grown silicon dioxide SiO2 passivation Aberle et al. As a result, the injection-dependent minority-carrier lifetime curves are different for the n- and p-type cases Fig. A significant drop in lifetime is observed at low injection on p-type wafers because electrons the minority carriers in p-type c-Si are more easily lost at the interface than holes via defect-assisted recombination.

This behavior cannot be attributed to bulk defects, because high-quality float-zone FZ wafers were used in this experiment. Notably, this drop in lifetime in the p-type case has a detrimental effect on the FF of completed solar cells see Section 4.

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Seller Notes:. Product Group:. Publication Year:. Trade Paperback. Publication Name:. Item Height:. Derek Lea. Item Length:. Item Width:. Item Weight:. Number of Pages:. About this product. Product Information If you are a digital artist, illustrator, cartoonist, graphic artist, designer, or serious hobbyist looking for new and interesting ways to use Photoshop, this is the book for you You already know how to use Photoshop as an image editing tool; now, challenge yourself and discover the more artistic aspects of the program with one of the world’s best teachers by your side.

Item Width. Item Weight. I really can’t recommend this book enough. The tutorials are easy to understand even when dealing with advanced techniques. It could be a bit much if you are brand new to Photoshop but I doubt it.

Here you can ask for help on problem areas from other readers and often the author himself and also post your own work that the lessons have hopefully helped you to create. An easy 5 stars, great work. I purchased this book on a whim and was pleasantly surprised by the quality of its content.

Lea takes readers step by step through simple and very complex design techniques. His instructions are easy to follow and, unlike many other Photoshop books I have picked up, just as easy to apply to other projects! Having access to the author through the reader forum on the book website makes this an even more useful tool. Any tips that might seem vague are easily explained by the man who wrote the book – and other readers that have overcome similar problems. I have worked through several books on Photoshop, but this has been the best by far!

I have been a fan of Derek Leas work for a number of years since first discovering his tutorials in Computer Arts magazine. I often emailed Derek asking him if he was going to write a book on advanced digital imaging techniques. Derek finally took the challenge of writing a book and to say that the wait was worthwhile is an under statement!

There are so many generic Photoshop books out there that I stopped looking at them a while ago. Then I found this. Derek Lea has written the definitive guide for artists who want to create within Photoshop.

I find the art so inspirational and the style of writing so easy to follow that I’d recommend it to anyone who wants to do something really cool with Photoshop. Lea also maintains a companion website to the book with an active forum.

Hoex, B. Ultralow surface recombination of c-Si substrates passivated by plasma-assisted atomic layer deposited Al2O3. Hofmann, M. Industrial type Cz silicon solar cells with screen-printed fine line front contacts and passivated rear contacted by laser firing. Holmes, P. Handbook of Thick Film Technology.

Electrochemical Publications, Glasgow. Fine-line printed contacts on crystalline silicon solar cells. Huster, F. Investigation of the alloying process of screen printed aluminium pastes for the BSF formation on silicon solar cells. A novel thin silicon solar cell with Al2O3 as surface passivation. Jiang, F.

Kane, D. Measurement of the emitter saturation current by a contactless photoconductivity decay method. Kang, J. Gettering in silicon. Ketola, B. Silicones for photovoltaic encapsulation.

Kimura, K. Recent developments in polycrystalline silicon solar cells. Kirkendall, E. Diffusion of zinc in alpha brass. AIME , — Kost, C. Krause, J. Microstructural and electrical properties of different sized aluminum alloyed contacts and their layer system on silicon surfaces. Energy Mater. Cells 95 8 , — Kray, D. Industrial LCP industrial emitter solar cells with plated contacts.

Lamers, M. C , 17— Lauermann, T. Enabling dielectric rear side passivation for industrial mass production by developing lean printing-based solar cell processes. The influence of contact geometry and sub-contact passivation on the performance of screen-printed Al2O3 passivated solar cells. Diffusion-based model of local Al back surface field formation for industrial passivated emitter and rear cell solar cells.

Li, Z. Microstructural comparison of silicon solar cells front-side Ag contact and the evolution of current conduction mechanisms. Surface and volume recombination in silicon solar cells. Dissertation, University of Utrecht. Low, R. High efficiency selective emitter enabled through patterned ion implantation.

Mandelkorn, J. Simplified fabrication of back surface electric field silicon cells and novel characteristics of such cells. Silver, Springs, pp. Mason, N. Meemongkolkiat, V. Investigation of modified screen-printing Al pastes for local back surface field formation. Mehta, S. PV pulse—technology shares, regional production trends, top suppliers, and the outlook for Melnyk, I. High throughput in-line acidic texturisation and edge isolation: an industrial reality. Metz, A.

Industrial high performance crystalline silicon solar cells and modules based on rear surface passivation technology. Micard, G. Advances in the understanding of phosphorus silicate glass PSG formation for accurate process simulation of phosphorus diffusion.

Miyajima, S. Hydrogenated aluminium oxide films deposited by plasma enhanced chemical vapor deposition for passivation of p-type crystalline silicon. Morita, H. Efficiency improvement of solar cell utilizing plasma-deposited silicon nitride. Mosel, F. Growth of high quality silicon mono ingots by the application of a magnetic cusp field in Cz puller. Moynihan, M. IPA free texturing of mono-crystalline solar cells. Hydrogenated silicon nitride for regeneration of light induced degradation.

Murray, J. The Al Si aluminum silicon system. Alloy Phase Diagr. Nagel, H. Determination of optical constants of semitransparent films and substrates for silicon solar cell applications. Nemet, G. PV learning curves and cost dynamics. In: Advances in Photovoltaics, , vol. Neuhaus, D. Industrial silicon wafer solar cells. Ohl, R. Light sensitive device. Patent No. Ohl, S. Increased internal quantum efficiency of encapsulated solar cells using two-component silicone as encapsulant material.

Panasonic press release April 10, Papet, P. Pospischil, M. Investigations of thick-film-paste rheology for dispensing applications. Correlations between finger geometry and dispensing paste rheology. Ralph, E. Recent advancements in low cost solar cell processing. Ramspeck, K. Light induced degradation of rear passivated mc-Si solar cells. Rauer, M.

Investigation of aluminum-alloyed local contacts for rear surfacepassivated silicon solar cells. Alloying from screen-printed aluminum pastes containing boron additives. Rein, S. Electrical and thermal properties of the metastable defect in boron-doped Czochralski silicon Cz-Si. Quantitative correlation of the metastable defect in Cz-silicon with different impurities. Richards, B. Comparison of TiO2 and other dielectric coatings for buried contact solar cells: a review.

Richter, A. Aluminium oxide for the surface passivation of high efficiency silicon solar cells. Reassessment of the limiting efficiency for crystalline silicon solar cells. Review on screen printed metallization on p-type silicon. Energy Procedia 21, 14— Add-on laser tailored selective emitter solar cells. Schmidt, J. Structure and transformation of the metastable boron- and oxygen-related defect center in crystalline silicon.

Scanning Nd:YAG laser system for industrially applicable processing in silicon solar cell manufacturing. Schubert, G. Thick film metallisation of crystalline silicon solar cells—methods, models and applications.

Formation and nature of Ag thick film front contacts on crystalline silicon solar cells. Current transport mechanism in printed Ag thick film contacts to an n-type emitter of a crystalline silicon solar cell. Schubert, M. Impact of impurities from crucible and coating on mc-silicon quality—the example of iron and cobalt.

Seibt, M. Gettering processes and the role of extended defects. Shi, Z. Mass production of the innovative Pluto solar cell technology. Shockley, W. Statistics of the recombinations of holes and electrons. Sinton, R. Contactless determination of current-voltage characteristics and minority carrier lifetimes in semiconductors from quasi-steady-state photoconductance data.

IEEE 85 5 , — Taguchi, M. Takayama, M. Large area high efficiency multicrystalline silicon solar cells. In: Technical Digest of Int. Tjahjono, B. Application of laser doped contact structure on multicrystalline solar cells.

Tobias, I. Crystalline silicon solar cells and modules. In: Luque, A. Trumbore, F. Solid solubilities of impurity elements in germanium and silicon. Bell Syst. Urrejola, E. Al-Si alloy formation in narrow p-type Si contact areas for rear passivated solar cells.

Silicon diffusion in aluminum for rear passivated solar cells. Back-contact solar cells: a review. Vermang, B. Direct tin-coating of aluminum rear contact by ultrasonic soldering.

Wagner, H. Improving the predictive power of modelling the emitter diffusion by fully including the phosphosilicate glass PSG layer. Wang, A. Weizer, V. Photondegradation effects in terrestrial silicon solar cells. Wenham, S. Buried-contact silicon solar cells. Buried contact solar cells. Australian Patent Wilking, S. Influence of hydrogen on the regeneration of boron-oxygen related defects in crystalline silicon.

Influence of hydrogen effusion from hydrogenated silicon nitride layers on the regeneration of boron-oxygen related defects in crystalline silicon. Influence of bound hydrogen states on BO-regeneration kinetics and consequences for high-speed regeneration processes. C , 2—8. Ximello, N. A new KOH-etch solution to produce a random pyramid texture on monocrystalline silicon at elevated process temperatures and shortened process time.

Yoshikawa, T. Solid solubilities and thermodynamic properties of aluminum in solid silicon. Zhao, J. C 41 42 , 87— Zulehner, W. Czochralski growth of silicon. Growth 65, — Introduction 2. Passivating c-Si Surfaces with a-Si:H 2. Losses in Silicon Heterojunction Solar Cells 4. Industrialization and Commercialization 5. Several key factors explain the success of this technology: Silicon is a well-studied semiconductor with known optoelectronic properties; it is abundant and nontoxic, and the price of multicrystalline silicon has witnessed an unprecedented drop in the last few years, partially because of a temporary production overcapacity, especially in Asia; and silicon solar cell technology has greatly benefited from the accumulated knowledge in semiconductor processing developed by the microelectronics community.

Carrier recombination in silicon is a well-understood phenomenon and its minimization is a key factor in obtaining high-efficiency solar cells.

We make a distinction between intrinsic recombination Auger and band-to-band radiative recombination and deep-defect-mediated recombination Richter et al.

This structure should feature perfectly passivated surfaces and contacts. Note that, with perfect contacts, the Voc represents the energetic distance between the quasi-Fermi levels, which themselves express the density of excess charge carriers present in the material as a consequence of shining light on it. An important reason why the Voc can never equal the bandgap of the absorber—1.

Despite this, it is possible to come close to the mV limit in real devices with excellent surface and contact passivation. Surface passivation has also improved: A number of dielectric passivation layers are available that can passivate p-type and n-type surfaces very well.

The former is known as chemical surface passivation and can be obtained by, e. The latter is known as field-effect passivation and is usually obtained by deposition of a fixed-charge dielectric on the surface under study, thereby repelling minority carriers inside the wafer from the defective surfaces.

Here, the most studied dielectric is aluminum oxide, which is a material that received significant attention in the last few years as a potential passivating layer for the rear surface of homojunction solar cells Agostinelli et al.

In all cases, contacts are needed to extract carriers from the solar cell. In standard homojunction solar cell technology, where the junction is fabricated by thermal diffusion or ion implantation, these contacts are usually defined by locally opening the dielectric passivating layers and making a direct Ohmic contact between the metal and semiconductor.

Qualitatively, this 76 Christophe Ballif et al. On the one hand, it should prevent generated carriers from being collected instantaneously, as this will lower the energetic splitting of the quasi-Fermi levels and thus reduce the voltage of the device. On the other hand, the contacts should be sufficiently electronically transparent to guarantee that carriers can be collected at the device terminals before they recombine in the wafer due to intrinsic recombination processes.

In this chapter, the focus will be on heterojunction solar cells with layers fabricated from thin films of amorphous silicon or related materials. First, a-Si:H passivates c-Si surfaces very well, with electrical properties that are on par with the best dielectrics available.

This property enables the fabrication of contacts that are selective for either electron collection when n-type a-Si:H is used , or hole collection when p-type a-Si:H is used. This is of significant utility, as it allows us to not simply make passivating contacts but also to escape the need for a homojunction in the wafer.

Depositions over areas of several square meters coupled with nanometric precision are commonplace. In , Fuhs et al. In the early s, a new type of tandem silicon solar cell was reported by Hamakawa et al. As the emitter of the bottom cell was made from a-Si:H as well, this is likely the first solar cell incorporating a silicon heterojunction for the emitter formation Hamakawa et al.

This makes the heterojunction concept also particularly attractive to fabricate emitters on substrates that would not withstand the temperatures usually involved in homojunction solar cell fabrication. This point gave Panasonic Sanyo at the time the motivation to incorporate silicon heterojunctions into their thin-film multicrystalline silicon solar cells in the late s Taguchi et al.

These cells were identified to suffer from substantial interface recombination. A first significant advance was made when a thin intrinsic a-Si:H layer was inserted between the doped emitter and wafer to alleviate this issue. This is the so-called heterojunction with intrinsic thin-layer HIT structure, which increased the efficiency up to From this, it was clear that both electron- and hole-collecting contacts need to be passivated, and both can be fabricated by planar heterojunction technology.

In the last 20 years, Panasonic has increasingly refined the heterojunction concept, even though the essential characteristics remained unchanged. Specific attention has been paid to improve surface passivation, lower the optical losses, and increase the fill factor FF of the devices. This sustained effort found its culmination in a reported solar cell efficiency of This device featured a Voc of mV, a value approaching the theoretical limit, underlining the particular appeal of this technology.

With the interdigitated-back-contact configuration, the same company reduced the current losses at the front of the cell 78 Christophe Ballif et al. Adapted with permission from De Wolf et al. Panasonic recently reached an efficiency of Recombination at surfaces In a working solar cell, generated carriers are collected at the relevant contacts or they recombine. Whereas the former process constitutes the external device current, the latter is purely a loss mechanism.

Prior to either of these two processes occurring, the generated carriers reside in the material, where they contribute to the voltage of the device. In open-circuit conditions, obviously no current flows, and thus the Voc is directly linked to carrier recombination processes. Microscopically, in c-Si, bulk recombination is usually caused by deep defects, which originate from impurities or crystal defects.

Such recombination is usually described by Shockley—Read—Hall recombination statistics. Deep-defect recombination is also of serious concern at clean silicon surfaces. The reason for this is the fact that the silicon lattice consists of covalent Si—Si bonds that must be broken at the surface. Depending on the precise surface orientation, each silicon surface atom will feature either one as on the silicon surface or two as on the silicon surface dangling bonds.

In this state, it can give up its electron positively charged state or it can host a second electron negatively charged state. The ease with which the dangling bond can move between these states, accepting either electrons from the conduction band or holes from the valence band, explains its high recombination activity and the need for surface passivation. Physics of passivation The microscopic passivation mechanism of c-Si by a-Si:H is most likely closely linked to hydrogenation of surface states, where the hydrogen is supplied from the passivating film.

For good passivation, it is necessary that the interface between the two materials be atomically sharp, i. For such films, low-temperature annealing can also improve the passivation properties. For isothermal annealing, it was found that, irrespective of the precise deposition conditions, the electronic properties always obey stretched-exponential laws over the annealing time De Wolf et al.

Based on this, it could be argued that the passivation is to a significant extent driven by microscopic rearrangement of hydrogen close to the interface. Comparison with the bulk properties of a-Si:H indicated that the dominant defect responsible for recombination must be the same both in the a-Si:H bulk and at a wafer surface, and that this defect is likely the silicon dangling bond De Wolf et al. Quite generally, the passivation properties of a-Si:H films mimic what occurs in their bulk, which includes effects such as light-induced degradation De Wolf et al.

Deposition of high-quality a-Si:H films Since the passivating intrinsic a-Si:H layers are of such importance for the final device, great care has to be taken during their deposition.

In particular, damage of the c-Si surface during deposition has to be limited as much as possible. The most common way of depositing these very thin layers is by plasma-enhanced chemical vapor deposition PECVD , using silane SiH4 —often mixed with H2 for an additional source of hydrogen—as the gas precursor, in a capacitively coupled parallel-plate reactor configuration. The development of such industrial reactors dedicated specifically to silicon heterojunction solar cell technology undoubtedly benefited from the knowledge gained in recent years by the thin-film transistor and thin-film silicon solar cell industries Shah et al.

Although the passivation properties of an a-Si:H film can generally be improved by thermal annealing De Wolf et al. It has been reported that device-grade, passivating intrinsic a-Si:H layers are deposited in plasma regimes close to the amorphous-to- micro- crystalline transition Descoeudres et al. With the aid of plasma diagnostics such as infrared absorption spectroscopy or optical emission spectroscopy, it is indeed found that the best as-deposited a-Si:H passivating films are obtained with low-cp plasmas, which correspond precisely to amorphous regimes close to the crystalline transition Strahm et al.

A possible way to further approach the transition without epitaxial growth on the c-Si surface is the use of H2 plasma treatments, either during Descoeudres et al.

Therefore, considering only the basic bulk properties of c-Si wafers, n-type material is better suited to reach high conversion efficiencies. Regarding surface passivation with a-Si:H, fundamental differences exist between n- and p-type wafers. As with bulk defects, the capture cross sections of surface defects, i.

The same phenomenon occurs for surface defects with thermally grown silicon dioxide SiO2 passivation Aberle et al. As a result, the injection-dependent minority-carrier lifetime curves are different for the n- and p-type cases Fig. A significant drop in lifetime is observed at low injection on p-type wafers because electrons the minority carriers in p-type c-Si are more easily lost at the interface than holes via defect-assisted recombination.

Higher low-injection lifetimes are obtained with such layers, due to the negative fixed charge present in this material Hoex et al. At high injection, on the other hand, the lifetimes are similar in both cases, and are limited by unavoidable Auger and radiative recombination.

Thus, there is the potential to reach very high Voc values, characteristic of the excellent surface passivation of silicon heterojunction solar cells, on both n- and p-type wafers, as shown by the relatively similar implied Voc values Fig. Such high-lifetime cells do indeed reach high injection at open circuit under 1-sun illumination. Wafer cleaning and texturing For silicon heterojunction solar cells, the wafer of choice is usually a monocrystalline silicon CZ wafer that is phosphorus doped and has surface 84 Christophe Ballif et al.

The injection levels corresponding to 1-sun illumination are marked by solid arrows, and the corresponding implied Voc values are given. The injection levels corresponding to the maximum power points MPPs of the finished devices under 1-sun illumination are marked by the dashed arrows.

Combined radiative and Auger recombination limits are shown by the solid lines Richter et al. Monocrystalline silicon is usually preferred to multicrystalline silicon because of the higher carrier lifetimes usually associated with the monocrystalline material.

In addition, the defined crystalline orientation of monocrystalline silicon allows for random-pyramid texturing. Such pyramids are formed by anisotropic etching of surfaces, which reveals pyramids with oriented facets Bean, This flatness is of considerable importance to deposit thin films of equal thickness during subsequent processing. Such surfaces are almost impossible to obtain on multicrystalline wafers. However, such wafers still require post-wafering processing steps such as gettering and hydrogenation to bring the bulk carrier lifetime to acceptable levels, casting doubt on whether this material is well suited for the fabrication of cost-effective silicon heterojunction solar cells.

The preparation of the wafer surfaces prior to film deposition usually consists of several steps, some of which can be combined. First, damage caused by wafer sawing is removed in an alkaline solution.

Next, the typical pyramidal texture is developed, also using an alkaline solution Bean, ; Papet et al. This process is followed by wafer cleaning. During this process, the impurities are removed, while the exposed silicon surface is terminated by hydrogen atoms. This yields chemical passivation, and can also stabilize the surface for some time following removal of the wafers from the chemical baths. Despite this, it is usually recommended to swiftly transfer the wafers into the deposition system.

Electron and hole collectors: Doped a-Si:H layers To give carriers generated in the silicon wafer an incentive to be collected, contacts specifically designed for the collection of electrons and holes must be designed. In principle, several approaches for forming such carrierselective contacts exist; in silicon heterojunction solar cells, this is achieved by depositing thin doped a-Si:H layers on the passivation layers.

For electron collection, a thin phosphorus-doped a-Si:H n film is used, whereas for hole collection a thin boron-doped a-Si:H p film is used. Though the doping efficiency for these materials may show some asymmetry— boron doping is well known to be difficult to achieve—the best devices reported to date rely on this type of contact. The precise contact formation, including the effect of the bulk and interface properties, has been the subject of intense study in recent years Bivour et al.

Note that, apart from directly forming hole and electron collectors in silicon heterojunction solar cells, highly doped a-Si:H layers can also be used in c-Si solar cells as a phosphorus or boron dopant source for diffusion into the c-Si substrate Seiffe et al.

As is well known in the thin-film silicon solar cell community, care has to be taken regarding cross-contamination if doped and intrinsic a-Si:H layers are successively deposited in a single PECVD chamber. Boron or phosphorus present in the a-Si:H on the reactor walls or substrate holder can be unintentionally incorporated into subsequent layers Collins, ; Roca i Cabarrocas et al. Similarly, dopant contamination in the intrinsic a-Si:H passivation layers of silicon heterojunction solar cells leads to reduced passivation quality and thus Voc more severely for boron than for phosphorus contamination.

To circumvent these boron and phosphorus cross-contamination issues, several solutions have been developed apart from using a multi-chamber PECVD system with chambers dedicated to i-, n-, and p-layer depositions : the deposition of a thick intrinsic coating on the reactor walls between layer depositions Platz et al. Recently, more groups have started to investigate the use of specific electron- and hole-collecting materials that are not necessarily silicon based.

For example, molybdenum oxide MoOx has been used in place of p-type a-Si:H as a hole-collecting layer. MoOx is a wide-bandgap material with a high work function. Therefore, it displays significantly higher transparency in the UV than p-type a-Si:H while maintaining the role of hole collector.

In silicon heterojunction solar cells, the deposited emitter is made of low-mobility a-Si:H and it is only 5—10 nm thick. Consequently, lowresistance lateral transport is not possible in the emitter, and—as in thin-film solar cells that face the same obstacle—a transparent conductive oxide TCO layer is required at the front side to provide a low-resistance current path to the metal fingers.

The thickness of the layer is almost always fixed at approximately 75 nm since it then conveniently behaves as an excellent anti-reflection coating with a reflectance minimum at nm. This is possible because most TCOs have refractive indices of approximately 2, the geometric mean of air and silicon. To reach the desired sheet resistance, instead of making the TCO layer thicker, the free-electron density is instead commonly tuned by adjusting the doping density.

This approach is effective but has a negative side effect: Parasitic absorption of infrared light by free carriers increases with increasing free-electron density, reducing Jsc discussed in detail later Holman et al. Conversely, increasing the electron mobility reduces sheet resistance and free-carrier absorption Schroder et al.

For bifacial solar cells, the requirements for the rear TCO layer are similar to those for the front layer, but higher TCO sheet resistance can often be tolerated because the rear fingers are frequently closer together and the sheet resistance that is relevant to the lumped series resistance is that of the wafer and the rear TCO layer in parallel assuming a front-emitter cell; for a rearemitter cell, this is true for the front TCO layer.

For a silicon heterojunction solar cell with full rear metallization, a TCO layer is not required for lateral transport—in fact, it is not clear that a TCO layer is required at all. While Bivour et al. In addition, Holman 88 Christophe Ballif et al. Near-bandgap p-polarized light that arrives at the rear TCO layer above the critical angle for internal reflection creates an evanescent wave that can be strongly absorbed in either the TCO layer itself or the subsequent metal reflector in the form of a surface plasmon polariton.

By reducing the TCO free-electron density to n nm, both losses are suppressed, increasing the path length of weakly absorbed light in the wafer and thus increasing Jsc. For an interdigitated-back-contact IBC silicon heterojunction solar cell, the requirements for the rear TCO layers are the same as for cells with full rear metallization though electrical contact needs to be made to both n- and p-type a-Si:H layers and no TCO layer is required at the front.

ITO is deposited by DC or RF sputtering in an argon atmosphere, and oxygen gas is added to tune the doping of the resulting layers through the density of oxygen vacancies Buchanan et al. Figure 2. To further increase mobility, researchers have explored doping indium oxide with tungsten IWO Lu et al. Lu et al. Koida et al. This result was reproduced by Barraud et al. ITO films of the same nominal thickness were deposited with identical conditions but varying oxygen partial pressure.

Characterization was performed with profilometry and Halleffect measurements. Sputtered aluminum-doped zinc oxide ZnO is occasionally used in silicon heterojunction solar cells in place of indium-based TCOs Maydell et al. Active-area Jsc values are given. Reproduced with permission from Barraud et al.

The two types of low-temperature paste are thermoplastic and thermoset Zicarelli et al. The choice of paste depends on the required solderability for interconnection, on the targeted aspect ratio, and on the application small cells for research or large-area devices. Silver nanopastes reach lower values but are prohibitively expensive and are hard to print thick enough. In other words, to reach similar finger-related losses as in diffused-junction c-Si cells, three times more paste has to be used.

A fivebusbar silicon heterojunction cell can, hence, have finger-related FF losses similar to a three-busbar cell fired at high temperature. Three other approaches to reduce silver consumption are: 1.

Low-temperature copper paste: Usually, such pastes include a low-meltingpoint alloy surrounding the copper particles. Some preliminary results were demonstrated Tokuhisa et al. The multi-wire approach is reported to reduce silver consumption to 40 mg per side of a cell Soderstrom et al.

The process is also compatible with bifacial cells. A W module with a multi-wire approach was demonstrated recently Kobayashi et al. Additionally, the multi-wire approach opens the possibility of other printing techniques for contacts, such as inkjet or offset printing, allowing a further reduction in silver usage Hashimoto et al.

Shown below are energydispersive X-ray maps of copper, nickel, and indium, and a top-view scanning electron microscope image of the finger displayed above. The ITO layer that is usually used as the front contact and anti-reflection coating forms a good barrier against copper diffusion and offers a natural conductor for direct plating.

There are many approaches for creating the pattern or the seed layer, including inkjet printing of hot-melt wax Hermans et al. In principle, copper metallization allows a large cost decrease compared to three- or even five-busbar silver-printed cells. However, it comes with the additional steps required to pattern the cell or to remove the mask. Record cells In recent years, several academic groups have started to investigate silicon heterojunction solar cells.

Meanwhile, companies have begun work on this technology as well. In the following tables we summarize the best reported results to date. Tables 2. Table 2. To put these results in perspective, in Table 2. In Table 2. These results underline the fact that there are several approaches to fabricate high-efficiency silicon heterojunction solar cells. Because no shadow losses are present and no contacting structures are needed at the front, such a design may offer the ultimate solution that combines high Voc and high Jsc.

In , Sharp presented exciting results with an IBC structure, the precise processing of which remains undisclosed. These were followed in by the spectacular new Table 2. The status column indicates whether the result was independently confirmed IC or appeared in a peerreviewed publication PR. With additional efforts, improved FF values can likely be obtained, which would open interesting roads toward commercialization of this technology.

Voc losses Losses in Voc are due to recombination. Here, as already argued, the passivation of c-Si surfaces by a-Si:H films is quite remarkable, eliminating most of the surface states present. Intrinsic bulk recombination includes Auger recombination and radiative recombination. For the former, which strongly depends on carrier density, empirical expressions are available Kerr and Cuevas, and recently have been revised Richter et al. Mitigation of the remaining defect recombination losses is one obvious way to obtain higher Voc values.

Another is to use thinner wafers combined with excellent passivated surfaces. In this case, for the same AM1. A concern when using thinner wafers, however, is infrared light management.

FF losses Causes of FF losses can be difficult to identify and suppress, since they come from different inter-dependent contributions. Shunts aside, FF losses in solar cells come from resistance to carrier transport through each layer and across each interface and from carrier recombination. In particular, the p-type layer must be heavily doped and sufficiently thick so as not to be depleted by the adjacent TCO; thicker layers, however, increase blue parasitic absorption and reduce Jsc.

This contact has to act as a band-to-band tunneling junction Kanevce and Metzger, , and is therefore also very sensitive to intra-band defect states in a-Si:H Taguchi et al. Note that if the work functions of the metallization 96 Christophe Ballif et al. Another approach to relax the constraints linked to the aforementioned FF-Jsc tradeoff is to reverse the classical cell structure and to place the p-n junction at the rear of the cell rear-emitter cell. This way, the TCO and p-type a-Si:H layers can be optimized mainly with respect to their electrical properties, since their optical role in the cell is of less importance Bivour et al.

Doing this can reduce FF losses Kobayashi et al. An Ohmic contact for electrons is needed, and this is relatively simple to realize in practice with sufficient doping of the n-type a-Si:H and TCO layers.

For typical a-Si:H films, the conduction and valence band offsets are around 0. Nevertheless, the valence band offset increases with the a-Si:H hydrogen content, for example, and can reach 0.

A valence band offset that is too large can have a dramatic effect on hole transport, blocking carriers and reducing FF Seif et al. Based on the lifetime measurements shown in Fig. Indeed, the minority-carrier density decreases from high to low values during an illuminated current—voltage measurement when moving from opencircuit to short-circuit conditions. The reduced lifetime at low injection in the p-type case reduces performance at maximum power point MPP compared to the n-type case, where the lifetime stays constant for decreasing injection Fig.

High Voc values are not sufficient to guarantee high FF values: Even though n- and p-type heterojunction solar cells have similar Voc values, cells on p-type wafers are less efficient Descoeudres et al. Jsc losses Losses in Jsc are caused by reflection and recombination, as well as transmission if the cell is bifacial or has interdigitated back contacts.

Jsc loss due to recombination is called parasitic absorption and refers to light that is absorbed but does not result in a collected electron—hole pair because the carriers recombine or thermalize, in the case of free-carrier absorption during transport. Parasitic absorption can occur in the absorber itself if the diffusion length is short, in highly doped supporting layers that exhibit free-carrier absorption e.

Current loss analysis is conveniently simplified in silicon heterojunction solar cells because their high lifetimes and consequently long diffusion lengths mean that parasitic absorption is strictly associated with light not absorbed in the wafer. The blue shaded area indicates front-surface reflection, the purple area indicates escape reflection, the green areas indicate parasitic absorption, and the red area indicates successful charge collection.

Though the current loss associated with each area is given, one must be careful: current lost is not the same as current gained if the loss mechanism is removed. For example, if infrared parasitic absorption were removed, Jsc would increase by 1. Grid shadowing 2. Reproduced from Holman et al. Shadowing from the front metal grid creates the largest Jsc loss.

Reducing it by narrowing the finger and busbars improves cell performance only if they are simultaneously made taller or more conductive so that their contribution to the lumped series resistance does not increase. Stencil printing is one approach to achieve higher-aspect-ratio metal lines Zicarelli et al. Parasitic absorption of blue light is responsible for the next largest loss, and is due to absorption in the front a-Si:H layers Fujiwara and Kondo, ; Holman et al.

The simplest fix is to make these layers thinner, but this comes at a price. If the intrinsic layer thickness drops below approximately 4 nm, it is no longer able to effectively passivate the surface because the electron wavefunction in the wafer penetrates through it and Voc drops Fujiwara and Kondo, ; Holman et al.

If the p-type layer is made thin, FF falls, which Bivour et al. An alternative approach is to make the front a-Si:H layers more transparent by either widening the bandgap by alloying with oxygen or carbon Einsele et al. Both remain active areas of research, spurred on by recent success with wide-bandgap layers by Fraunhofer ISE and Silevo Feldman et al.

Yet another approach is to change the device design so that all of the a-Si:H layers are at the rear interdigitated back contacts or at least the p-layer is at the rear rear emitter so that the n-layer at the front can be very thin without being depleted. The final large Jsc loss is due to infrared parasitic absorption.

This light bounces around many times in the solar cell, and is absorbed parasitically by free carriers in both the front and rear TCO layers, as well as in the rear metal reflector Holman et al.

The rear metal reflector is also lossy—even for an excellent reflector like silver—for p-polarized light arriving at the back surface with respect to the appropriate pyramid facet above the critical angle for internal reflection. These photons are not totally internally reflected; instead they undergo attenuated internal reflection as in a Fourier transform infrared spectroscopy measurement performed in the attenuated total reflection mode because the evanescent wave interacts with lossy rather than perfectly transparent media the TCO and metal layers Harrick and Dupre, ; Holman et al.

In particular, if the evanescent wave reaches the metal reflector it will excite surface plasmon polaritons that absorb the incident photon energy. Imperfect light trapping—taken here to mean the path length enhancement of light in the wafer in the absence of absorption—is not as large a loss as is commonly thought.

The random-pyramid texture that is common in all industrial monocrystalline silicon solar cells is so effective that only approximately 0.

Nevertheless, Ingenito et al. Front surface reflectance is also not a particularly large Jsc loss after encapsulation because the glass and polymer of the module introduce another, intermediate refractive index. Consequently, double-layer anti-reflection coatings are seldom used.

General status The first silicon heterojunction products were sold by Sanyo in Their current annual production capacities reached approximately MW at the end of now under Panasonic.

Research activities in the field started at various institutes in —, first with the demonstration of high Voc values i. Descoeudres et al. At the same time, the expiration of key Sanyo patents triggered renewed interest from several industrial actors.

Sunpreme offers bifacial modules based on silicon heterojunction solar cells on wafers. Choshu Industry Co. CIC has also set up a 30 MW production line and has demonstrated The equipment maker Roth and Rau now under Meyer Burger has developed PECVD and sputtering tools specifically for silicon heterojunction cell mass manufacturing, and demonstrated They have indicated a takt time of approximately 90 s for 56 wafers per carrier in production.

To obtain such high voltages, minority-carrier bulk lifetimes in the millisecond range are required. This is typically achieved using n-type CZ material. Some groups have also reported good results with properly processed n-type quasi-mono wafers Jay et al. As discussed previously, n-type c-Si material is chosen for two reasons: It is generally less sensitive to metal impurities than p-type c-Si, and it is not sensitive to the boron—oxygen complex Glunz et al.

Several wafer manufacturers have demonstrated the capability to grow full n-type CZ ingots with bulk lifetimes in excess of several milliseconds, even after multiple charge pulling.

The simulations were performed with PC1D using a model presented in Ballif et al. The model, implemented in the one-dimensional device simulator PC1D, is described in Ballif et al.

Above a bulk lifetime of 4 ms, there is only a marginal difference in efficiency between the three doping levels. All of the values reported here were obtained with a nominal Voc of mV for a 4 ms bulk lifetime , Jsc of Notably, as silicon heterojunction solar cells operate close to high-injection conditions at MPP and both surfaces have full-area contacts, the base doping is less critical to the series resistance than in passivated emitter and rear contact PERC cells.

Consequently, a larger doping variation—like that obtained in typical n-type ingot growth—can be tolerated. The results are displayed for various bulk lifetimes and wafer thickness. The plot shows that, as expected, for quasi-perfect contacts and high Christophe Ballif et al. The simulations were also performed with PC1D. For reduced bulk lifetimes, thinner wafers and higher base doping mitigate the losses, leading to efficiencies between Finally, depending on the initial quality of the silicon wafer, material improvements can be obtained by gettering or hydrogenation.

CIC also reported the use of a thermal-donor annealing step. The discrepancies between the values for cells with equivalent Voc stem from the properties of the a-Si:H layers and from the temperature dependence of the FF: Transport through the heterocontacts can be improved by the temperature in some cases, leading to a stable or even increased FF with the temperature and, hence, to a more favorable temperature coefficient.

Note that in such cases, however, the efficiency in standard test conditions might also be lower than for cells without activated transport. Metallization Several approaches to metalizing silicon heterojunction solar cells have been presented previously.

For production, screen printing is simple and reliable and is therefore commonly used. Replacing busbars with multi-wires reduces the silver required for the finger, but the cost of the low-temperature soldering alloy might partly offset the reduced silver usage.

In the long term, plating may be the best option for high efficiencies at low cost. However, the additional process complexity and moderate efficiency improvement, compared to screen printing, might delay its introduction until silver becomes significantly more expensive.

In particular, soldering on low-temperature paste is a more delicate process than on high-temperature paste, and alternative approaches, e.

Notably, the packaging of silicon heterojunction modules can benefit from many of the approaches developed for thin-film technology, in which TCOs and low-temperature pastes are also present. Tools and production technologies In its most simple form, silicon heterojunction technology requires a mix of traditional and new pieces of equipment. We describe here some of the key Christophe Ballif et al.

We note that several device configurations are possible. By nature, silicon heterojunction cells can be made with the emitter at the front or at the rear of the cell, and excellent results have been reported in both configurations Descoeudres et al.

This translates into an intrinsic bifaciality that can be employed, e. Immediately prior to a-Si:H deposition, the wafer is dipped in a diluted HF solution to strip the oxide. The texturing and cleaning can strongly impact the solar cell performance, requiring good control of the chemical quality.

Though some cleaning recipes have been reported Edwards et al. Good results have been reported both at An advantage of parallel-plate PECVD is the direct transfer of knowledge gained from thin-film silicon films for, e. Careful PECVD reactor design is required to ensure uniform gas distribution and a uniform plasma even close to the electrode edges Howling et al. The typical deposition rate of a-Si:H layers is in the range of 0. It can be inferred that process times below 1 min are achievable for each of the four a-Si:H layers i, n, i, p deposited in a standard silicon heterojunction solar cell.

It should process such batches with a takt time of 90— s, including handling, giving a nominal annual capacity of 60— MW, depending on the uptime. If the samples are transported on carriers, there is the possibility of contamination of the chamber with a reused carrier. Therefore carrier and contamination management can play an important role in achieving good results.

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