Fabricating High-Conduction and High-Transparency Tungsten-Doped Zinc Oxide Films by Pulse Laser Deposition Technique

Abstract

Utilising a pulse laser deposition technique, 1.0 wt.% tungsten-doped zinc oxide (WZO) films were fabricated under different growth temperatures (200–400 °C), and their structural, optical, morphological, and electrical properties were discussed. The crystalline structures of the WZO target and films were examined by X-ray diffraction (XRD) analysis, and preferred orientations along the strong c-axis (002) were strongly observed for all growth temperatures. All WZO films demonstrated transparencies above 75%, along with a wide spectral range (400–700 nm). Their bandgap values ranged between 3.21 and 3.35 eV and their optimised resistivity, which was significantly influenced by the growth temperature, was measured as 1.97 × 10−3 Ω cm. Further, the electrical characteristics of the WZO films were investigated under different W-doping amounts (1.0–9.0 wt.%) and a constant growth temperature (300 °C), and the results indicated that the carrier mobility showed an opposite tendency to the W-doping percentage. In addition, the elemental compositions of the WZO films and pristine ZnO films were comparatively studied in terms of Zn, O, and W contents, via X-ray photoelectron spectroscopy (XPS) analysis.