Extended-Short-Wavelength Infrared Alinassb And Inpassb Detectors On Inas

We have fabricated and characterized AlInAsSb- and InPAsSb-absorber nBn infrared detectors with 200 K cutoff wavelengths from 2.55 to 3.25 mu m. Minority-carrier lifetimes determined by microwave reflectance measurements were 0.2-1.0 mu s in doped n-type absorber materials. Devices having 4 mu m thick absorbers exhibited sharp cutoff at wavelengths of 2.9 mu m or longer and softer cutoff at shorter wavelengths. Top-illuminated devices with n+ InAs window/contact layers had external quantum efficiencies of 40-50% without anti-reflection coating at 50 mV reverse bias and wavelengths slightly shorter than cutoff. Despite the shallow-etch mesa nBn design, perimeter currents contributed significantly to the 200 K dark current. Dark currents for InPAsSb devices were lower than AlInAsSb devices with similar cutoff wavelengths. For unoptimized InPAsSb devices with 2.55 mu m cutoff, 200 K areal and perimeter dark current densities at -0.2 V bias in devices of various sizes were approximately 1x10(-7) A/cm(2) and 1.4x10(-8) A/cm, respectively.