The Photoluminescence Properties of β-Ga2O3 Thin Films

In this work, beta-Ga2O3 thin films were deposited by pulsed laser deposition (PLD) with changing oxygen pressure in the chamber. The theta-2 theta scan x-ray diffraction (XRD) results reveal that the quality of the thin film obviously deteriorates when the oxygen pressure is greater than 0.1 Pa. Photoluminescence (PL) spectra measured at room temperature show that the major emission band can be separated into three Gaussian bands at about 370 nm (similar to 3.34 eV), 410 nm (similar to 3.03 eV), and 453 nm (similar to 2.74 eV), respectively. Using this analysis combined with x-ray photoelectron spectroscopy (XPS), we found that the three luminescence peaks originate from a self-trapped hole (STH) (between two OII-s sites), (V-Ga + V-O)(1-) and VGa2-(tetrahedral site), respectively. This work provides us a way to tune the emission of beta-Ga2O3 thin films.