Growth and characterisation of potentiostatically electrodeposited Cu 2O and Cu thin films

Abstract

Cuprous oxide and copper thin films were potentiostatically electrodeposited in an acetate bath. Voltammetric curves were used to investigate the growth parameters; deposition potential, pH and temperature of the bath. Deposition potential dependency on the structural, morphological, optical and electronic properties of the films were investigated by the X-ray diffraction measurements, scanning electron micrographs, absorption measurements and dark and light current–voltage characterisations. It was observed that single phase polycrystalline Cu 2O can be deposited from 0 to − 300 mV Vs saturated calomel electrode (SCE) and co-deposition of Cu and Cu 2O starts at − 400 mV Vs SCE. Further increase in deposition potential from − 700 mV Vs SCE produces single phase Cu thin films. Single phase polycrystalline Cu 2O thin films with cubic grains of 1–2 μm can be possible within the very narrow potential domain around − 200 mV Vs SCE. Enhanced photoresponse in a photoelectrochemical cell is produced by the Cu 2O thin film prepared at − 400 mV Vs SCE, where Cu is co-deposited with Cu 2O with random distribution of Cu spheres on the Cu 2O surface. This study reveals that a single deposition bath can be used to deposit both Cu and Cu 2O separately and an admixture of Cu–Cu 2O by controlling the deposition parameters.