Shunt effect in polycrystalline GaAs solar cells

Thin-film polycrystalline GaAs solar cells have the potential for reduced cost while retaining high efficiency. However, solar cells made from polycrystalline GaAs have historically had poor open-circuit voltages. Models that account for these low voltages suggest that in order to make solar cells with high voltages it is necessary to use material with very large grains. As an alternative cause for the low voltages, the presence of Schottky barriers due to inverted grain boundaries is proposed. If this is the case, the requirements on grain size will be reduced. The existence of grain boundary inversion in polycrystalline solar cells is demonstrated, and it is shown that contacting grain boundaries leads to lower voltages