Structural and optical properties of ZnO thin films produced by filtered cathodic vacuum arc

Polycrystalline ZnO films have been deposited by filtered cathodic vacuum arc with various substrate temperatures and bias voltages. The films deposited at room temperature are amorphous. The films grown at 230 and 430°C oriented in the (002) and (103) directions. Strong near-band edge room temperature photoluminescence emission has been observed in the film deposited at 230°C under floating bias. This is attributed to the reduced oxygen vacancies as determined by Raman spectroscopy. The bias voltage and high substrate temperature (up to 430°C) will induce more defects, resulting in broad band tails near the band edge. The optimized ZnO film has a transmittance which is over 80%.