Structural and Electrical Characterizations of Electrodeposited p-Type Semiconductor Cu[sub 2]O Films

Abstract

The p-type semiconductor cuprous oxide (Cu2O)(Cu2O) film has been of considerable interest as a component of solar cells and photodiodes due to its bandgap energy of 2.1eV2.1eV and high optical absorption coefficient. We prepared Cu2OCu2O films on a conductive substrate by electrodeposition at 318K318K from an aqueous solution containing copper sulfate and lactic acid. The structural and electrical characterizations of the resulting films were examined by X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption measurements, and the Hall effect measurement, respectively. The resistivity varied from 2.7×104to3.3×106Ωcm2.7×104to3.3×106Ωcm , while the carrier density was from 1012to1014cm−31012to1014cm−3 and the mobility from 0.4to1.8cm2V−1s−10.4to1.8cm2V−1s−1 , depending on the preparation conditions, i.e., solution pH and deposition potential. The carrier density was sensitive to the atomic ratio of Cu to O in the films and the mobility to the grain size.