Characterization of the structural and optical properties of ZnO thin films doped with Ga, Al and (Al+Ga)

Abstract

Transparent thin films of Al-doped ZnO (AZO), Ga-doped ZnO (GZO) and codoped Al + Ga ZnO (AGZO) were deposited on soda-lime glass by RF magnetron sputtering. The influence of aluminum and gallium concentrations in zinc oxide (ZnO) films on structural and optical properties of thin films were studied. XRD results shown that the obtained films were with a hexagonal wurtzite structure and preferentially oriented perpendicular to the substrate surface. Atomic force microscopy (AFM) evidenced that the type of doping modifies the microstructure of thin films. Raman spectroscopy was used to study structural properties of complex oxides at a local level. Optical transmission measurements show a small decrease of transparency films when the dopant content increases. The shift of the optical band gap of AZO films with increasing Al and Ga content suggest the enhancement of carrier concentration.