Enhanced Photoelectric Performance of β-Ga₂O₃ Phototransistors via NH₃ Plasma Pretreatment for Ultra-Sensitive Solar-Blind UV Detection

This work presents $\beta $ -Ga2O3 phototransistors with exceptional photoelectric performance, enhanced by NH3 plasma pretreatment prior to Al2O3 dielectric deposition. The devices achieve a remarkable responsivity ( ${R}\text {)}$ of $1.3 \times 10^{{6}}$ A/W and a record-high detectivity ( ${D}^{\ast } \text {)}$ of $2.8 \times 10^{{19}}$ Jones under 254 nm ultraviolet (UV) light. Rapid photoresponse is demonstrated, with a rise time ( $\tau _{\text {r}}\text {)}$ of 90 ms and a decay time ( $\tau _{\text {d}}\text {)}$ of 1 ms under a 1 Hz pulsed UV light source. These superior characteristics are attributed to NH3 plasma-induced improvements at the Al2O3/ $\beta $ -Ga2O3 interface, including reduced trap density and enhanced dielectric adhesion. The findings provide a promising pathway to advance $\beta $ -Ga2O3 phototransistors for ultra-sensitive, solar-blind UV detection with rapid response capabilities.