Structural and electrical characterizations of electrodeposited p-type semiconductor Cu2O films

The p-type semiconductor cuprous oxide (Cu2O) film has been of considerable interest as a component of solar cells and photodiodes due to its bandgap energy of 2.1 eV and high optical absorption coefficient. We prepared Cu2O films on a conductive substrate by electrodeposition at 318 K 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 x 10(4) to 3.3 x 10(6) Omega cm, while the carrier density was from 10(12) to 10(14) cm(-3) and the mobility from 0.4 to 1.8 cm(2) V-1 s(-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. (c) 2005 The Electrochemical Society. All rights reserved.