Surface and bulk passivation of GaAs solar cell on Si substrate by H2+PH3 plasma

Abstract

A promising passivation method for GaAs solar cell grown on Si substrate (GaAs/Si solar cell) by phosphine-added hydrogen (PH3/H2) plasma exposure has been envisaged. The defect-hydrogenation and the surface-phosphidization effects of GaAs/Si solar cell are realized simultaneously by this single passivation process. Consequently, surface recombination states are reduced and the minority carrier lifetime is increased, resulting in a significant reduction in saturation current density (J0) of the GaAs/Si p–n junction. High open-circuit voltage (0.93 V) and fill factor (80.9%) are obtained for the PH3 plasma exposed GaAs/Si solar cells. As a result, the conversion efficiency is increased from 15.9% to 18.6%. This approach provides a simple and effective method to improve the photovoltaic properties of GaAs/Si solar cell.