Effects of preparation temperature on optical and electrical characteristics of (111)-oriented Cu2O films electrodeposited on (111)-Au film

The (111)-oriented Cu2O films with a 2.0-eV-bandgap energy were prepared by electrodeposition on a (111)-oriented Au/Si wafer substrate at the preparation temperatures from 298 to 323 K, and the structural, optical, and electrical characterizations were carried out by X-ray absorption spectra measurements, X-ray diffraction, scanning electron microscopic observations, optical absorption spectra, photoluminescence spectra measurements, and Hall effect measurements. The photoluminescence spectra and electrical characteristics changed depending on the temperature. The 1.52-eV-visible light that originated from the copper vacancies weakened with a decrease in the preparation temperature, and the emission of the slight 2.0-eV-visible light due to the re-combination of excitons was observed for the Cu2O film prepared at 298 K. The hole density related to the copper vacancies decreased and the mobility increased with a decrease in the preparation temperature, and the maximum mobility of 21 cm(2) V-1 s(-1) could be obtained at 303 K. (c) 2011 Elsevier B.V. All rights reserved.