Performance Improvement of a β-Ga2O3-Based Solar-Blind Metal Oxide Semiconductor Field-Effect Phototransistor Using In Situ Ozone Pretreatment Technology

In this work, we demonstrated a high-performance beta-Ga2O3 solar-blind metal oxide semiconductor field-effect phototransistor (SBPT) with low-temperature in situ ozone (O-3) pretreatment technology. The Ga-O bonding quality and oxygen content of the beta-Ga2O3 surface before and after O-3 pretreatment were first determined by X-ray photoelectron spectroscopy (XPS). The percentage of substable O to total O decreased from 8.6% to 2.7% after the in situ O-3 pretreatment, and the peaks of substable Ga-O bonds moved closer to those of stable Ga-O bonds, indicating an improvement in the Ga-O bonding quality. Compared with SBPT without O-3 pretreatment, devices with O-3 pretreatment exhibited excellent photoelectrical properties, including a large photo-to-dark current ratio (PDCR) of 1.4 x 10(7), a high UV-C/UV-A rejection ratio (R-254 nm/R-365 nm) of 2.1 x 10(7), a high responsivity (R) of 4.37 x 10(6) A/W, a large quantum efficiency (EQE) of 2.2 x 10(7)%, and a high detectivity (D*) of 2.8 x 10(18) Jones. The rise time (tau(r)) and decay time (tau(d)) are extracted to be 70 and 23ms after O-3 pretreatment. The optimized parameters of the device illustrate that low-temperature in situ O-3 pretreatment technology is a simple but effective approach to improve the performance of beta-Ga2O3-based SBPT.