Pushing Detection Wavelength Toward 1~μ m by Type II InAs/GaAsSb Superlattices With AlSb Insertion Layers

We report on a short wavelength p-i-n detector using type II InAs/GaAsSb superlattices with AlSb insertion layers. The photoresponse is narrow-band like (δλ/λ=7.6%) and the wavelength at the response maximum is 1.08 μm at 77 K, the shortest wavelength reported until now. Insertion of AlSb thin layers not only helps reach such a short detection wavelength, but also reduces the dark current significantly. When a large positive bias voltage like +3 V is applied to the detector even at room temperature, the photoresponse is still clearly obtained, testifying a very small dark current of the device. The quantum efficiency of the device is 23% at 1.08 μm at 77 K, corresponding to the responsivity of 0.21 A/W. The resistance-area product at zero bias, R0A, is 1.7×107Ω·cm2at 77 K and is 121 Ω · cm2at 300K. The Johnson noise limited detectivity D* of the device is 1.1×1013Jones for the wavelength of 1.08 μm at 77 K.