High-performance GaAs homojunction far-infrared detectors

摘要

Abstract: A high performance, bias tunable, p-GaAs homojunction interfacial workfunction internal photoemission far-IR detector has been demonstrated. A responsivity of 3.10 $POM 0.05 A/W, a quantum efficiency of 12.5 percent and a detectivity D* of 5.9 $MUL 10$+10$/ cm $ROOT Hz/W, were obtained at 4.2K, for cutoff wavelengths from 80 to 100 $mu@m. The bias dependences of quantum efficiency, detectivity, and cutoff wavelength have been measured and are well explained by the theoretical models, where the cutoff wavelength is modeled by a modified high density theory, and the quantum efficiency is predicted by scaling the free carrier absorption coefficient linearly with the doping concentration. The effect of the number of layers on detector performance and the uniformity of the detectors have been discussed. A comparison with Ge:Ga photoconductive detectors suggest that a similar or even better performance may be obtainable. !20