Solar cells can be made from a wide range of semiconductor materials. In the following sections, we will discuss:

• Silicon (Si)—including single-crystalline Si, multicrystalline Si, and amorphous Si
• Polycrystalline thin films—including copper indium diselenide (CIS), cadmium telluride (CdTe), and thin-film silicon
• Single-crystalline thin films—including high-efficiency material such as gallium arsenide (GaAs)

First, though, we provide an overview of aspects that relate to all materials. This discussion serves as a basis for the more detailed section on individual materials. The aspects we will cover are crystallinity, absorption, bandgap, and complexity of manufacturing.