High-Performance Ultraviolet Photodetector Arrays Based on Recessed-Gate HEMT with a Buried p-GaN Layer
Chuankai Liu, Yu Wang, Hangzan Liu, Hao Qian, Lixiang Han, Xiaozhou Wang, Zhaoqiang Zheng, Wei Gao, Jingbo Li
Abstract
GaN, due to its large band gap and high carrier mobility, has been widely used in fast-response ultraviolet (UV) photodetectors (PDs). The existing junction-based and two-dimensional electron gas (2DEG)-based devices have different focuses on the performance of ultraviolet detection. To achieve comprehensive performance, we fabricate a high-performance UVPD utilizing a GaN recessed-gate high electron mobility transistor (HEMT) integrated with a p-GaN buried layer. Benefiting from the effective p-GaN/u-GaN depletion junction, the device has a low dark current of 1.75 × 10 –9 A at a voltage bias ( V ds ) of 2 V. Under 365 nm illumination, the recovery of 2DEG is obtained and results in an ultrahigh photocurrent exceeding 1 mA at V ds = 2 V. As a result, a maximum responsivity ( R ) of 532 A/W, an external quantum efficiency of 1.81 × 10 5 %, and a specific detectivity ( D *) of 1.09 × 10 14 Jones are attained at a light power density ( P ) of 0.24 mW cm –2 . Moreover, the influence of oxygen plasma treatment on the gate recess is explored. The response time is shortened from 1.07/1.20 to 0.79/1.05 ms, and the maximum I light / I dark ratio is increased by more than 10 times. Such high performance substantiates that the structure of GaN recessed-gate HEMT with p-GaN buried layer architecture holds great promise for the creation of an outstanding UV photodetector.