Thin conductive gallium‐doped zinc oxide grown by pulsed laser deposition

Abstract

Abstract— A new process to prepare ZnO:Ga thin conductive oxide (TCO) films with excellent optical and electrical properties is described in this work. The Ga‐doped ZnO targets used for thin‐film deposition were prepared from powder materials obtained with a novel ceramic processing technique (combustion synthesis). The deposition of the ZnO:Ga thin films was performed on glass at different substrate temperatures (150–300°C) in an ultra‐high‐vacuum laser ablation system. High transmittance (>85%) of light in the visible range and sheet resistance values as low as 18 Ω/□. were measured on films with thicknesses of 200 nm deposited on glass at 300°C. From optoelectronic measurements we observed a good gallium‐doping efficiency and a widening of the bandgap when varying the substrate temperature from 150 to 300°C, in good agreement with other work. X‐ray diffraction and high‐resolution transmission electron microscopy measurements revealed that the films grow preferentially oriented in the (002) crystallographic direction of the ZnO grains.