Comparison study of V-doped ZnO thin films on polycarbonate and quartz substrates deposited by RF magnetron sputtering

Abstract

Vanadium (V) doped ZnO (VZO) thin films were deposited on flexible polymer and quartz substrates by RF magnetron sputtering, and influences of deposition parameters of V concentration, RF power and growth temperature on resistivity, transmittance and crystallinity were investigated. For the polymer substrates, both a high heat-resistant polycarbonate (PC) film and a functional-layer-coated PC film were adopted. The resistivity decreased gradually but the transmittance was worsened with increasing V concentration. Low RF power and high growth temperature improved both transparency and conductivity. By over-coating of the functional layers, c-axis orientation was deteriorated while low-resistivity and high-transmittance characteristics were achieved. Resistivity and average visible-transmittance (wavelength=450–800nm) of VZO films on untreated PC and over-coated PC substrates were 0.98mΩcm and 83.7%, and 1.2mΩcm and 80.3%, respectively, at V concentration of 2at.%, RF power of 100W and growth temperature of 175°C. VZO films on the polymer substrates had slightly high resistivity but nearly the same optical transmittance, compared to those on quartz, under the identical deposition parameters. These results indicate that good electrical and optical properties can be achieved for the VZO films on PC substrate.