Thickness-dependent quasi-two-dimensional β-Ga2O3 solar-blind photodetectors prepared via GaSe oxidation†

Abstract

Thermal management, in both electronic power devices and opto-electronic ultraviolet (UV) photodetectors based on gallium oxide (Ga₂O₃) materials, has been regarded as an important technical approach to enable systems to operate stably for long periods of time. Specifically, in Ga₂O₃-based solar-blind UV photodetectors, the low thermal conductivity of the material would result in severe heat accumulation in the device, leading to a slow photoresponse speed which in turn causes significant problems such as signal distortion, data loss, and system delay. Therefore, it is crucial to minimize heat accumulation and improve heat dissipation efficiency from the perspective of materials. Low-dimensional materials, with large specific surface areas, would exhibit faster heat dissipation rates than bulk counterparts in heat conduction, heat convection, and heat radiation mechanisms. In this work, quasi-two-dimensional β-Ga₂O₃ with different thicknesses were synthesized by thermal oxidation of two-dimensional (2D) GaSe nanoflakes with a van der Waals (vdW) layered structure. It was suggested that the thinness of GaSe limits the thickness of β-Ga₂O₃ after oxidation, improves the specific surface area of the device, and effectively suppresses the accumulation of hot carriers in the system, thus providing a feasible solution for solving the thermal problem of wide-bandgap optoelectronic devices.