Simulation and optimization of enhanced back-gated GaN-based HEMT ultraviolet photodetector with a high photo-to-dark current ratio

In this work, the performance of an innovative structure of an enhanced back-gated GaN-based HEMT ultraviolet photodetector is investigated using Silvaco Atlas. The simulation results show that an increase in both the doping concentration and width of the p-GaN region positively affects the ability of the device to suppress leakage current. In addition, an increase in the thickness of the n-GaN layer positively affects the saturation photocurrent of the device. Finally, the influence of each structural parameter of the device on the device performance is investigated in detail, and the appropriate device parameter conditions for achieving a photo-to-dark current ratio (PDCR) of 1013 are drawn. When the embedding depth of the p-GaN region is 11 nm, the gate voltage is −9 V and the p-GaN region width is 0.7 μm, and the device is able to achieve a PDCR of 1013 with a maximum photocurrent of 1.595 mA. When the p-GaN region width is 0.5 μm, the embedding depth of the p-GaN region is 15 nm and the gate voltage is −1 V, and the device is able to achieve a PDCR of 1013 with a photocurrent of 1.301 mA.