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 recombination 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 cm2 V−1 s−1 could be obtained at 303 K.