Effect of Oxide buffer layers on the optical and electrical properties of Ga-doped zinc oxide thin film

The effects of oxide buffer layers on the optical and electrical properties of sputtered Gallium-doped zinc oxide (GZO) films were intensively investigated for developing the electrodes of photonic devices, which demand high optical transmittance and low resistivity. The use of Al2O3 and SiO2 buffer layers could increase transmittance of GZO films to 90.69% around the wavelength of 550 nm by controlling the optical spectrum. The resistivity of the deposited GZO films was much dependent on the deposition condition of O-2 ratio during buffer layer deposition. It is considered that the carrier mobility of GZO films on SiO2 buffer is highly related to the lattice crystallinity of SiO2 and GZO films. In contrast, on the Al2O3 buffer layer, rough surface morphology could increase the resistivity of GZO films due to the doping effect of diffused Al atoms.