The influence of grain boundaries on the performance efficiency of polycrystalline gallium arsenide solar cells

Abstract

The effect of grain boundaries on the current-voltage characteristics of n + p polycrystalline GaAs solar cells has been studied in some detail. For the sake of convenience, a theoretical model that involves the solution of the continuity equation, and considers recombination at the grain boundary, grain boundary space-charge region, and the bulk of the semiconductors, has been used for the study. Calculated results for diffusion length, short-circuit current, open-circuit voltage, fill factor, and conversion efficiency have been compared with available experiments. Good agreement between the theory and the experiments attest to the validity of the model. The study indicates that grain size and doping levels are important device parameters for optimizing the solar cell properties.