Polarization assisted self-powered GaN-based UV photodetector with high responsivity

Abstract

In this work, a self-powered GaN-based metal-semiconductor-metal photodetector (MSM PD) with high responsivity has been proposed and fabricated. The proposed MSM PD forms an asymmetric feature by using the polarization effect under one electrode, such that we adopt an AlGaN/GaN heterojunction to produce the electric field, and by doing so, an asymmetric energy band between the two electrodes can be obtained even when the device is unbiased. The asymmetric feature is proven by generating the asymmetric current-voltage characteristics both in the dark and the illumination conditions. Our results show that the asymmetric energy band enables the self-powered PD, and the peak responsivity wavelength is 240 nm with the responsivity of 0.005 A/W. Moreover, a high responsivity of 13.56 A/W at the applied bias of 3 V is also achieved. Thanks to the very strong electric field in the charge transport region, when compared to the symmetric MSM PD, the proposed MSM PD can reach an increased photocurrent of 100 times larger than that for the conventional PD, even if the illumination intensity for the light source becomes increased.

Highly Sensitive Ultraviolet Photodetector Based on an AlGaN/GaN HEMT with Graphene‐On‐p‐GaN Mesa Structure

“…Although the response speed is faster than the several recent reports on UV Photodetectors, still it is not good enough and needs to be reduced for ultrafast applications. [10,45] The dry etching-induced defects act as the trap on the surface causing a higher response time in the photodetector with a p-GaN mesa structure. [45] In addition, under 365 nm illumination, the photogenerated carrier should pass through the AlGaN barrier which hinders the speed of photogenerated carrier collection and thus the rise time.…”

“…[51] It was reported that various factors such as increasing illumination power, bias voltage, AlGaN band edge illumination (i.e., shorter illumination wavelength), reducing the persistent photoconductivity effect, and post treatment can improve the response speed of photodetector. [25,28,45,52,53]…”

Recent advances in self‐powered and flexible UVC photodetectors

“…Wang et al. [ 163 ] fabricated a GaN‐based self‐powered UVC photodetector by MOCVD. Their device was constructed with an asymmetric MSM structure with the addition of AlGaN.…”

Controllability of β-Ga2O3 single crystal conductivity by V doping

“…The continuous development of materials, has enabled the application of semiconductors in photodetectors, 1,2 solar cells, 3,4 light-emitting diodes, 5,6 and various other fields. 7–9 Beta-gallium oxide (β-Ga 2 O 3 ) crystals, as an outstanding representative of the emerging semiconductors, have been increasingly applied in semiconductor fields such as high-power electronic devices, 10 ultraviolet detectors, 11 and gas sensors 12 largely owing to their excellent material properties.…”