Effect of growth temperature on properties of β-Ga2O3 films grown on AlN by low-pressure chemical vapor deposition

Abstract

In this work, thin films of β-Ga2O3 were prepared on AlN substrates using low-pressure chemical vapor deposition (LPCVD). The effects of growth temperature on the crystal structure, surface morphology, chemical composition, and photoluminescence properties of the synthesized β-Ga2O3 thin films were then systematically investigated. The results indicated that various films grown at different temperatures in the range of 550–850 °C had a preferred growth orientation in the planar direction (−201). The surface roughness was seen to reduce gradually as the growth temperature was raised. However, excessive temperature (850 °C) led to a reduction in the densification of the prepared films. The surface chemistry of the films was analyzed using X-ray photoelectron spectroscopy (XPS) and the O/Ga ratio of the optimal film was calculated to be 1.49, which is quite close to the optimal stoichiometric ratio of 1.5. Multiple luminescence bands were obtained in the photoluminescence spectra of the films taken at room temperature, where the blue emission formed the dominant bands. The results of the study suggest that the growth temperature has a significant impact on the film properties and that appropriately increasing the growth temperature leads to substantial improvement in the overall quality of the β-Ga2O3 thin films.