Uncooled InAs0.09Sb0.91 photoconductors with cutoff wave-length extended to 11.5 μm

Uncooled InAsSb photoconductors were fabricated. The photoconductors were based on InAs0.05Sb0.95 and InAs0.09Sb0.91 thick epilayers grown on InAs substrates by melt epitaxy (ME). Ge immersion lenses were set on the photoconductors. The cutoff wavelength of InAs0.09Sb0.91 detectors is obviously extended to 11.5 µm, and that of InAs0.05Sb0.95 detectors is 8.3 µm. At room temperature, the peak detectivity of D λp* at wavelength of 6.8 µm and modulation frequency of 1 200 Hz is 1.08×109 cm·Hz1/2·W−1 for InAs0.09Sb0.91 photoconductors, the detectivity D* at wavelength of 9 µm is 7.56×108 cm·Hz1/2·W−1, and that at 11 µm is 3.92×108 cm·Hz1/2·W−1. The detectivity of InAs0.09Sb0.91 detectors at the wavelengths longer than 9 µm is about one order of magnitude higher than that of InAs0.05Sb0.95 detectors, which rises from the increase of arsenic (As) composition in InAs0.09Sb0.91 materials.