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

This work presents <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga2O3 phototransistors with exceptional photoelectric performance, enhanced by NH3 plasma pretreatment prior to Al2O3 dielectric deposition. The devices achieve a remarkable responsivity (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}\text {)}$ </tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.3 \times 10^{{6}}$ </tex-math></inline-formula> A/W and a record-high detectivity (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${D}^{\ast } \text {)}$ </tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.8 \times 10^{{19}}$ </tex-math></inline-formula> Jones under 254 nm ultraviolet (UV) light. Rapid photoresponse is demonstrated, with a rise time (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\tau _{\text {r}}\text {)}$ </tex-math></inline-formula> of 90 ms and a decay time (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\tau _{\text {d}}\text {)}$ </tex-math></inline-formula> of 1 ms under a 1 Hz pulsed UV light source. These superior characteristics are attributed to NH3 plasma-induced improvements at the Al2O3/<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga2O3 interface, including reduced trap density and enhanced dielectric adhesion. The findings provide a promising pathway to advance <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga2O3 phototransistors for ultra-sensitive, solar-blind UV detection with rapid response capabilities.