InAsSb thick epilayers applied to long wavelength photoconductors

InAs_0.052Sb_0.948 epilayers with cutoff wavelengths longer than 8 μm were successfully grown on InAs substrates using melt epitaxy (ME). Scanning electron microscopy observations show that the interface between the epilayers and substrates is flat, indicating the good quality of the epilayers, and the thickness of the epilayers is 40 μm. Photoconductors were fabricated using InAs_0.052Sb_0.948 thick epilayers grown by ME. Ge optical lenses were set on the photoconductors. At room temperature, the photoresponse wavelength range was 2–10 μm. The peak detectivity D_λp^* reached 5.4 × 10⁹ cm·Hz^1/2·W⁻¹ for the immersed detectors. The detectivity D^* was 9.3 × 10⁸ and 1.3 × 10⁸ cm·Hz^1/2·W⁻¹ at the wavelength of 8 and 9 μm, respectively. The good performance of the uncooled InAsSb detectors was experimentally validated.