GRAIN-BOUNDARY EDGE PASSIVATION OF GAAS FILMS BY SELECTIVE ANODIZATION

Solar cells built on polycrystalline gallium arsenide usually have very leaky reverse characteristics and, consequently, low open-circuit voltage. These problems arise from the effect of the Schottky diode made on the grain boundary, which behaves like n+-material. This diode shunts the active Schottky solar cell and deteriorates its performance characteristics. In this letter we describe the use of selective-anodization techniques to provide an insulating barrier over the edge of the grain boundary in order to passivate it. Leakage current reduction of 5-6 decades has been achieved by this method, with both aqueous and nonaqueous anodization methods.