Other Semiconductor Materials. Like silicon, all PV materials must be made into p-type and n-type configurations to create the necessary electric field that characterizes a PV cell. But this is done a number of different ways, depending on the characteristics of the material. For example, amorphous silicon's unique structure makes an intrinsic layer (or i layer) necessary. This undoped layer of amorphous silicon fits between the n-type and p-type layers to form what is called a "p-i-n" design.

Polycrystalline thin films like copper indium diselenide (CuInSe₂) and cadmium telluride (CdTe) show great promise for PV cells. But these materials can't be simply doped to form n and p layers. Instead, layers of different materials are used to form these layers. For example, a "window" layer of cadmium sulfide or similar material is used to provide the extra electrons necessary to make it n-type. CuInSe₂ can itself be made p-type, whereas CdTe benefits from a p-type layer made from a material like zinc telluride (ZnTe).

Gallium arsenide (GaAs) is similarly modified, usually with indium, phosphorous, or aluminum, to produce a wide range of n- and p-type materials.

More:

• An Atomic Description of Silicon
• The Silicon Molecule
• Introducing Phosphorous
• Introducing Boron
• Other Semiconductor Materials
• Absorption and Conduction