Tungsten-doped ZnO transparent conducting films deposited by direct current magnetron sputtering

Abstract

Highly conducting and transparent thin films of tungsten-doped ZnO (ZnO:W) were prepared on glass substrates by direct current (DC) magnetron sputtering at low temperature. The effect of film thickness on the structural, electrical and optical properties of ZnO:W films was investigated. All the deposited films are polycrystalline with a hexagonal structure and have a preferred orientation along the c-axis perpendicular to the substrate. The electrical resistivity first decreases with film thickness, and then increases with further increase in film thickness. The lowest resistivity achieved was 6.97 × 10 −4 Ω cm for a thickness of 332 nm with a Hall mobility of 6.7 cm 2 V −1 s −1 and a carrier concentration of 1.35 × 10 21 cm −3. However, the average transmittance of the films does not change much with an increase in film thickness, and all the deposited films show a high transmittance of approximately 90% in the visible range.