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 3-5μm atmosphere window have been fabricated; their structural, electrical and optical characteristics have been investigated. The detectors show peak response wavelength λ_p at 3.85μm, with spectral width Δλ/λ_p of 4.6% and 7.2% at 1 and 5V bias voltages, respectively. Very low dark current of the detectors has been observed. At 2V bias the dark current is below 1nA at 77K and remains low value of 10nA at 150K. The background limited infrared performance temperature T_BLIP as high as 165 K has been measured.