One of the scientific discoveries of the computer semiconductor industry that has shown great potential for the PV industry is thin-film technology. Polycrystalline thin-film devices require very little semiconductor material and have the added advantage of being easy to manufacture. Rather than growing, slicing, and treating a crystalline ingot (required for single-crystal silicon), we sequentially deposit thin layers of the required materials. Several different deposition techniques are available, and all of them are potentially cheaper than the ingot-growth techniques required for crystalline silicon. Best of all, these deposition processes can be scaled up easily so that the same technique used to make a 2-inch x 2-inch laboratory cell can be used to make a 2-foot x 5-foot module (in a sense, a huge cell!). Like amorphous silicon, the layers can be deposited on various low-cost substrates (actually "superstrates," see Transparent Conductors) like glass or plastic in virtually any shape—even flexible plastic sheets.

Single-crystal cells have to be individually interconnected into a module, but thin-film devices can be made monolithically (as a single unit). Layer upon layer is deposited sequentially on a glass superstrate, from the antireflection coating and conducting oxide, to the semiconductor material and the back electrical contacts.

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