Investigation of substrate effect on Co-doped ZnO thin films prepared by thermionic vacuum arc technique

Abstract

In this paper, the substrate effect on cobalt-doped ZnO thin films and crystal defects on optical properties of the sample have been investigated. The structural, elemental, surface and optical properties of the films were characterized using X-ray diffraction (XRD), atomic force microscopy, field emission scanning electron micro-scopy and UV-vis spectrophotometry. The XRD results confirm the polycrystalline nature and formation of ZnO (10 0) plane for both substrates was detected. Metal oxide and bimetal oxide structures were determined using by XRD analyses. Average crystallite size of the films has been computed as 20 and 25 nm on the glass and Si substrates, respectively. The thicknesses of the films were recorded as 85 and 90 nm on the glass and Si sub-strates, respectively. The mean transmittance value was measured as 71 %. The band gap value of Co-doped ZnO thin film was calculated as 3.22 eV. The Urbach energy was achieved as 227 meV depending on the lattice distortions and structural defects. According to obtain results, TVA is a promising method for Co doped ZnO thin film production.