Low-frequency noise and interface states in GaAs homojunction far-infrared detectors

Low-frequency noise characteristics of p-GaAs homojunction interfacial work-function internal photoemission (HIWIP) far-infrared (FIR) detectors are reported. The noise was found to exhibit 1/f behavior related to interface states at frequencies below 1 kHz and frequency independent shot noise at higher frequencies. The noise expressions correctly predict the dark current noise behavior, and provide a means of estimating both the gain and energy distribution of the interface states. The interface state density is estimated to be in the order of 10¹¹ cm^-2. It has been shown that the estimated gain and noise equivalent power are in good agreement with the previous results obtained via optical measurements