High efficiency indium tin oxide/indium phosphide solar cells

Abstract

Solar cells have been fabricated by rf sputter depositing indium tin oxide onto single crystal p-type indium phosphide. Four different substrate doping densities have been used but in all cases the dopant was zinc and the wafers were 〈100〉 oriented. The optimum doping density from the range studied was 3×1016 cm−3 and devices based on such substrates have yielded total area efficiencies up to 16.2% using the air mass 1.5 spectrum normalized to 100 mW cm−2, which correspond to active area efficiencies of 19.1%. A doping density less than the optimum yielded devices with excessive series resistance. Higher doping densities led to a marked loss of red response.