Influence of the Substrate Temperature and Ag Incorporation on the Properties of Reactively DC Co-Sputtered Ag:TiO2 Thin Films

This study reports on the influence of substrate temperature on the properties of Ag-doped TiO2 thin films. The films were deposited by reactive DC co-sputtering of Ti and Ag targets at different substrate temperatures and Ag target sputtering powers. Grazing incident X-ray diffractometer confirmed that all films were polycrystalline with dominant peak oriented along (101) planes representing the anatase TiO2 phase. The average grain size of the samples improved with increase in deposition temperature. At a substrate temperature of 450, the samples had a dominant peak representing the rutile phase, suggesting partial transformation from anatase to rutile phase. The electrical conductivity of the samples increased with increase in substrate temperature; however, the average solar transmittance was decreased. Ag doping increased the electrical conductivity of the TiO2 samples by one order of magnitude compared to the undoped ones. A good compromise between the electrical conductivity (1.304 (cm)-1) and solar transmittance ( > 62%) was obtained at a substrate temperature of 400 and Ag dopant concentrations of 0.2% and 0.28% as determined by Rutherford Backscattering measurements. These results demonstrate the potential of Ag doping and optimisation of deposition conditions for the realisation of TiO2 based transparent conducting oxide that meets requirements for practical applications in optoelectronic devices.