High-speed ultraviolet photodetector based on p-gan gate hemt for flame monitoring

Abstract

The p-GaN gate high electron mobility transistor (HEMT) with a 2.0x10(-5) cm(2) sensitive area as a UV photodetector (PD) has been designed and fabricated in this study. AlGaN/gallium nitride (GaN) heterostructure was adopted to get a 2-D electron gas (2DEG) as a conductive channel, resulting in a high photoresponsivity of 8.07x10(4) A/W, a sharp cutoff wavelength at 360 nm, high UV-to-visible rejection ratio of 1.80x10(6) , rise and decay time of 0.12 and 1.0 ms, respectively. The dark current of 5.44x10(-7) A, the photocurrent of 4.42x10(-3 )A at 5 V, the external quantum efficiency (EQE) of 2.77% x10(5) %, and the detectivity of 8.31x10(14) Jones for the UV PD were determined under a low UV light intensity of 5 mW/cm(2) at 360-nm UV illumination. The obtained results show that the performance of as-fabricated UV PD based on AlGaN/GaN HEMT is significantly improved compared to the literature. This device, which has lower noise equivalent power (NEP) and enhanced detectivity features compared to existing ones, is a promising candidate for military and space applications.