The impact of barrier modulation on carriers transport in GaN quantum well infrared detectors

Abstract

GaN quantum well infrared detectors are affected by the epitaxy process and the polarization electric field within the quantum well, making it difficult to fabricate actual devices and regulate their performance. This study utilized the APSYS software to build a transport model for GaN quantum well infrared detectors. Based on the optimal quantum well structure GaN/Al_0.8Ga_0.2N with an absorption peak wavelength around 1550 nm, the modulation of barrier width is used to elucidate the control of E1 energy level in the quantum well, as well as the variation patterns of absorption spectra for quantum well intersubband transitions(ISBT) and polarization electric fields. Under the influence of polarization electric fields, the devices exhibit completely opposite changes in current when subjected to positive and negative biases, respectively. By using Gauss transient spectroscopy, the influence of triangular barriers on the photoelectron transport on the E1 energy level was investigated, and it was determined that the optimal barrier width is 3 nm. At this width, the device exhibits the fastest relaxation within the well and transport between wells. By analyzing the AC impedance, the equivalent circuit of the device was obtained and the rationality of the circuit structure was demonstrated.