Influence of polarization effects on photoelectric response of AlGaN/GaN heterojunction p-i-n photodetectors

Abstract

Based on the simulation of the polarization effect by the sheet charge layer approximately, the energy band structures and electric field distributions of AlGaN/GaN heterostructures with different doping concentrations of p-AlGaN and polarization effects are calculated by self-consistenly solving the Poisson-Schrödinger equations. The corresponding photoelectric response is calculated and discussed by solving the carriers continuity equation. The results show the interaction between the doping concentration and the polarization effect has an important influence on the performance of the p-i-n detector. Specially, under the condition of complete polarization, a high doping concentration in the p-AlGaN layer will result in a narrow depletion region in p-AlGaN layer and the i-GaN layer will be depleted easily, which corresponds to a low photocurrent. Similarly, a strong polarization will result in a wide depletion region in p-AlGaN and high photocurrent for the same doping concentration in p-AlGaN layer. Finally, the effect of temperature on the performance of the detector is calculated and analyzed. It is concluded that AlGaN/GaN heterostructure p-i-n ultraviolet detector can be used in the high temperature environment.