Texture evolution mechanism of pulsed laser deposited in-doped Ga2O3 film affected by laser fluence and its application in solar-blind photodetector

Abstract

This work explored the crystal structural, optical bandgap, and morphological texture evolution of pulsed laser deposited In-doped Ga2O3 films grown on sapphire substrate at different laser fluence from 1.0 to 2.6 J/cm2. The in situ optical emission spectroscopy was carried out to monitor the plasma radicals generated during the deposition. All the deposited films were crystallized and some clusters were formed because of high deposition temperature and rapid surface diffusion of indium (In). The growth rate and the crystallinity of the film increased and then declined with increasing laser fluence. The texture evolution mechanism of the films has been proposed firstly. The rapid diffusion of In, the sputtering and reflection effect of plasma species exist in whole films’ deposition process, which has a significant impact on the texture characteristics of the films. The clusters emerging on film surface were the crystallized In-rich InGaOx nanoparticles consisting of β-Ga2O3 and cubic In2O3 phases. Metal-semiconductor-metal solar-blind photodetectors were also fabricated and analyzed to illustrate the effect of laser fluence. The elaboration of texture evolution mechanism and effect of laser fluence on the properties of the In-doped Ga2O3 films and photodetectors is very beneficial for its application in high performance photoelectric devices.