Structural, optical and morphological evolution of Ga2O3/Al2O3 (0001) films grown at various temperatures by pulsed laser deposition

This study systematically investigated the structural, optical, and morphological evolution of Gallium oxide (Ga2O3) films deposited at different substrate temperatures on Al2O3(0001) using pulsed laser deposition (PLD). The thickness of the Ga2O3 films was standardized in order to eliminate its effect on the film properties. The effect of substrate temperature from room temperature to 600 degrees C on the film's transmittance, crystalline structure, chemical composition and surface morphology, was explored. The plasma species generated during the deposition of the PLD process were monitored and analyzed employing in situ optical emission spectroscopy. The deposition rate of the films decreased with increasing substrate temperature. X-ray photoelectron spectroscopy was used to detect both Ga3+ and Ga (+) oxidation states in all prepared films, which indicated substoichiometric Ga2O3 films deficient in oxygen. The percentage of non-lattice oxygen decreased with increasing substrate temperature. At optimal condition, mono-crystaline 8-Ga2O3 was produced with a high visible and near-infrared transmittance, large grain size and smooth surface, which is suitable for the application in high-performance power electric devices and photoelectronic devices.