BIAS EFFECTS IN HIGH-PERFORMANCE GAAS HOMOJUNCTION FAR-INFRARED DETECTORS

A high performance, bias tunable, p-GaAs homojunction interfacial work function internal photoemission far-infrared detector is demonstrated. A responsivity of 3.10+/-0.05 A/W, a quantum efficiency of 12.5%, and a detectivity D of 5.9 X 10(10) cm root Hz/W were obtained at 4.2 K for cutoff wavelengths from 80 to 100 mu m. The bias dependences of th e quantum efficiency, detectivity, and cutoff wavelength were measured and are well explained by the theoretical model. The effect of the la yer number on detector performance and the uniformity of the detectors are discussed. A comparison with Ge:Ga photoconductive detectors sugg ests that similar or even better performance may be obtainable with a far-infrared detector. (C) 1997 American Institute of Physics. [S0003- 6951(97)03144-6].