Copper Oxide Thin Films Deposited By Radio Frequency Magnetron Sputtering

Copper is abundant in nature,non-toxicity and low production cost.It has two main oxidation phases,cupric oxide?CuO?and cuprous oxide?Cu₂O?.In addition,there is another oxidation phase,paramelaconite?Cu₄O₃?,which is metastable.The three oxides have good application in solar cells,lithium batteries and catalysis due to their excellent optical and electrical properties,which attracted the attention of many researchers.In this paper,a high purity copper?99.995%?was used as a sputtering target by Radio Frequency reactive magnetron sputtering,and copper oxide thin films were deposited in a mixed atmosphere of argon and oxygen.The films were characterized by FTIR,XRD,Step Profiler and Optical Fiber Spectrometer.The effects of oxygen flow,radio frequency power,working pressure and substrate temperature on film structure,deposition rate and optical properties were investigated.The results are summarized as follows:The single phase CuO,Cu₂O and Cu₄O₃ thin films can be prepared by changing the experimental parameters?oxygen flow rate,radio frequency power and working pressure?.The deposition rate of Cu₂O and Cu₄O₃ films is obviously higher than that of CuO films.The high oxygen flow rate and the working pressure could produce the phenomenon of target poisoning,so the deposition rate of the CuO film decreased obviously.The optical properties of CuO,Cu₂O and Cu₄O₃ have been characterized,all three copper oxides?CuO,Cu₂O and Cu₄O₃?are direct bandgap.The effect of deposition temperature on polycrystalline cuprous oxide film was studied.It is found that the preferred orientation of Cu₂O films is affected by deposition temperature,and the optical band gap of Cu₂O films is related to the preferred orientation of Cu₂O,and the?200?preferred orientation of Cu₂O film,corresponding to the lower optical band gap?about1.97 eV?,the?111?preferred orientation corresponding to the higher optical band gap?about 2.23 eV?.