Phosphine-added hydrogen plasma passivation of GaAs solar cell on Si substrate

Abstract

The improvement of the GaAs solar cell on Si substrate (GaAs/Si solar cell) has been studied by treating phosphine-added hydrogen plasma (PH/sub 3//H/sub 2/ plasma) exposure. Phosphidization of GaAs surface and defect-passivation of entire GaAs bulk layer are realized simultaneously. As a result, surface recombination states are reduced, and the minority carrier lifetime is increased. Furthermore, the reduction of interface (GaAs/AlGaAs) recombination velocity is confirmed. For PH/sub 3//H/sub 2/ plasma exposed GaAs/Si solar cell, high open-circuit voltage and fill factor are obtained. Consequently, the conversion efficiency is increased from 15.9% to 18.6%.