ABSTRACT
While crystalline silicon presently dominates solar systems in global markets, other semiconductor-based solar cells continue to compete with silicon for market share. Cadmium telluride (CdTe), copper indium gallium selenide (CIGS), gallium arsenide (GaAs), and amorphous silicon (Si) are all semiconductors suitable for fabrication into PV cells that are sufficiently thin to be flexible and cost less than thicker crystalline silicon geometries. Noncrystalline amorphous silicon has a disordered structure and is significantly less efficient than crystalline silicon but offers low-cost, flexible structures that can open the door to installation on irregular surfaces where crystalline silicon is impractical. On the other end of the cost spectrum, GaAs PV cells are relatively expensive but meet solar energy needs in applications where high performance and resistance to ultraviolet radiation is critical, such as in aerospace and other space applications. In the middle of the cost spectrum, CdTe and CIGS can be integrated into traditional terrestrial solar installations and are second only to silicon in market share. This chapter addresses these second-generation, semiconductor-based PV technologies whose energy conversion efficiencies are competitive with silicon-based PV cells and offer benefits that silicon does not.
