GaAs multilayer p+-i homojunction far-infrared detectors

Abstract

A molecular beam epitaxy grown wavelength tunable GaAs p+-i homojunction interfacial work-function internal photoemission far-infrared detector is developed. The multilayer (p+-i-p+-i-…) detector structures consist of 2, 5, and 10 emitter layers. Experimental results are explained in terms of the number of emitter layers and the doping concentrations of the emitter layer. A detector with 10 multilayers and an emitter layer doping concentration (Ne) of 3×1018 cm−3 shows a current responsivity of 2 A/W, an effective quantum efficiency of 9.2% (at 26.3 μm) with a cutoff wavelength of 85 μ and the noise equivalent power of 2.18×10−12 W/Hz at 4.2 K.