Physical properties of indium zinc oxide and aluminium zinc oxide thin films deposited by radio-frequency magnetron sputtering

Abstract

Indium-doped zinc oxide (IZO) and aluminium-doped zinc oxide (AZO) thin films were grown by radio-frequency (RF) magnetron sputtering onto optical glass substrates and their structural, morphological, and optical properties were discussed in terms of varying the sputtering power as 40 W, 60 W, 80 W, and 100 W. No heating substrate or any post-thermal treatment was performed. The structural features were analyzed by grazing incidence X-ray diffraction and revealed the amorphous phase for IZO samples, while the AZO thin films inherited the Wurtzite structure of zinc oxide. The morphological properties were investigated by atomic force microscopy (AFM), in tapping mode and scanning electron microscopy (SEM). The AFM images showed relatively uniform and smooth surfaces for all prepared structures. The optical transmission spectra proved the excellent theoretical values of transparency for metallic oxides in the visible region of the electromagnetic spectrum, i.e. ∼60% for IZO and ∼70% for AZO. The obtained results showed that even without any thermal treatment the structural, morphological, and optical properties of IZO and AZO thin films prepared by RF magnetron sputtering are similar with those for samples subjected to medium or high temperatures.