Gallium oxide nanocrystals for self-powered deep ultraviolet photodetectors

Zero-dimensional colloidal nanocrystals (NCs) of gamma-phased gallium oxide ( gamma -Ga2 O3 ) were successfully synthesized using the sol-gel method, resulting in nanocrystals with high crystallinity. Heterojunction photodetectors were then constructed by employing spin-coating technology to deposit gamma -Ga2 O3 NCs film of varying thicknesses onto p -type GaN substrates. The resulting devices demonstrated selfpower capability through a photovoltaic effect when exposed to ultraviolet light illumination. Notably, a device with a 300 nm thick active layer, annealed in 400 degrees C, exhibited a responsivity of 6.7 x 10-3 A W-1 , a detectivity of 3.10 x 1011 Jones, and an external quantum efficiency of 3.2 % under 254 nm light illumination at 0.16 mW cm-2 , all without the need for an external power supply. These findings suggest promising practical applications for such photodetectors in single-point imaging systems. This study presents a straightforward and viable approach for developing high-performance and self-powered ultraviolet photodetectors based on zero-dimensional gamma -Ga2 O3 NCs, thereby opening up possibilities for various photonic systems and applications that do not rely on an external power supply. (c) 2024 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.