Design and Simulation of InGaN/GaN p–i–n Photodiodes

InGaN ternary alloys with their band gaps varying from 0.7 to 3.4 eV, are very promising for photodetector devices operating from UV to IR wavelength range. Using Silvaco–Atlas software, an In0.1Ga0.9N/GaN based p–i–n photodiode is designed and the J–V characteristics, the spectral responsivity, the frequency response and the cut‐off frequency as a function of InGaN thickness are studied. The photodiode exhibits a high reverse breakdown voltage of 38 V, a peak responsivity of 0.2 A W−1 at 0.343 μm wavelength and a cutoff frequency of 400 MHz under an applied reverse bias voltage of 2 V and for a 0.1 μm i‐InGaN layer, in good agreement with simulated and experimental results found in literature. It is found that an optimum i‐layer thickness of 1.5 μm for the maximum cutoff frequency of 4 GHz attributed to the predominance of the limitation in capacitance effect on the cutoff frequency at low i‐layer thickness and the transit time on the cuttoff frequency for high i‐layer thickness. For this i‐layer thickness, the highest peak responsivity about 0.244 A W−1 at 0.384 μm wavelength is achieved. InGaN ternary alloys are very promising for photodetectors operating from UV to IR wavelength range and can be used in spatial optical communications, medical and biological applications. In this paper, an InGaN/GaN p–i–n photodiode is simulated and the DC and AC responses as a function of InGaN thickness are studied. The simulation and modeling reported in this work can be used to optimize the InGaN/GaN photodetectors and developing new generation of optoelectronic devices.