Controlled synthesis of GaSe microbelts for high-gain photodetectors induced by the electron trapping effect

Abstract

GaSe microbelts were successfully synthesized using Ga/Ga₂Se₃ as the precursor mixture, where excess Ga was required to serve as the metal catalyst. Meanwhile, a spontaneously oxidized surface amorphous oxide (GaO_x) layer formed, which induced a built-in electric field perpendicular to the surface. Benefiting from this effect, a GaSe microbelt-based photodetector attained a high responsivity of ∼3866 A W⁻¹ and a photoconductive gain of up to ∼1.06 × 10⁴. This study sheds light on the controlled synthesis of microstructures and provides a device design concept for high-performance micro/nano optoelectronics.