Experimental Study of InP-Based InAlAs/InGaAs Quantum Well Infrared Photodetectors Operating at the 3-5 μm Wavelength Region

Gas source molecular beam epitaxy grown InP-based InAlAs/InGaAs quantum well infrared photodetectors operating at 3-5 μm atmosphere window have been fabricated; their structural, electrical and optical characteristics have been investigated. The detectors show peak response wavelength λ P at 3.85 μm, with spectral width Δ λ / λ P of 4.6% and 7.2% at 1 and 5 V bias voltages, respectively. Very low dark current of the detectors has been observed. At 2 V bias the dark current is below 1 nA at 77 K and remains low value of 10 nA at 150 K. The background limited infrared performance temperature T BLIP as high as 165 K has been measured.