Effect of Ga doping concentrations, substrate temperatures and working pressures on the electrical and optical properties of ZnO thin films

We fabricated Ga-doped ZnO (GZO) thin films on glass substrate by RF magnetron sputtering method with different conditions of Ga 2 O 3 concentration, substrate temperature and working pressure. Next we investigated the electrical, optical and structural properties of the GZO thin films. At a substrate temperature of 300 °C, a working pressure of 1 mTorr, and a Ga 2 O 3 concentration of 3 wt%, the GZO thin films showed the lowest resistivity of 3.16 × 10 −4 Ω cm, a carrier concentration of 7.64 × 10 20 cm −3 and a Hall mobility of 25.8 cm 2 /Vs. Moreover, the GZO thin films exhibited the highest (002) orientation under the same conditions and the full width at half maximum of X-ray peak was 0.34°. All GZO thin films showed the optical transmittance of more than 80 % in the visible range regardless of working conditions. The Burstein–Moss effect was observed by the change of doping concentration of Ga 2 O 3 . The GZO thin films were fabricated to have the good electrical and optical properties through optimizing doping concentration of Ga 2 O 3 , substrate temperature, working pressure. Therefore, we confirmed the possibility of application of GZO thin film as transparent conductive oxide used in flat panel display and solar cell.