Effects of the Preparation Procedure and In2O3 Thickness on the Electrical and Photovoltaic Properties of In2O3/CuInSe2 Heterostructures

The high performance parameters of solar cells based on CuInSe2 (~20% efficiency) have prompted intense research in this material. In2O3/CuInSe2 heterostructures were produced by growing indium oxide layers on bulk single-crystal and polycrystalline p-type CuInSe2 substrates using thermal oxidation and magnetron sputtering. The substrates were prepared by cleaving or abrasive polishing and chemical etching. The resistivity of the In2O3 layers was measured as a function of temperature and layer thickness, and the current-voltage characteristics and spectral response of the heterostructures were analyzed. The results indicate that the structures exhibit reduced reflection losses at oxide thicknesses below 0.5 mum. The reduced thickness of interfacial layers owing to the low process temperature in the case of magnetron sputtering makes it possible to extend the spectral region of photosensitivity of the heterostructures.