GaP/Si heterojunction solar cells

The world record efficiency and open circuit voltage for crystalline silicon solar cells are held by a-Si/Si heterojunction devices. While a-Si provides excellent surface passivation, these heterojunction devices are limited by non-ideal optical and electronic properties. Gallium phosphide is a candidate material for replacing a-Si in a heterojunction device, promising lower parasitic absorption and better carrier mobilities. In this work, we present our results in growing high quality GaP thin films directly on Si using a two-step nucleation and growth scheme with metalorganic chemical vapor deposition, characterization, and x-ray photoelectron spectroscopy band offset measurements toward realizing a GaP/Si heterojunction device.