GALVANOSTATIC DEPOSITION AND ELECTRICAL CHARACTERIZATION OF CUPROUS-OXIDE THIN-FILMS

Semiconducting cuprous oxide (Cu2O) thin films, important for low cost solar cell and oxygen or humidity sensor applications, were galvanostatically deposited at 40-60-degrees-C on copper substrates. The deposition kinetics, studied up to a film thickness of about 20-mu-m, was found to be linear and independent of deposition temperature. The observed film growth rate was in excellent agreement with the growth rates predicted from Faraday's law of electrolysis. The deposited films exhibited a preferred (200) orientation. The current voltage characteristics of the electrodeposited Cu2O/Cu diodes exhibited a metal-insulator-semiconductor type of behaviour, suggesting the presence of a thin interfacial insulating layer between Cu2O and copper. The electrical conductivity of Cu2O films was found to vary exponentially with temperature in the 145-300-degrees-C range with an associated activation energy of 0.79 eV.