Pushing Detection Wavelength Toward $1~\mu \text{m}$ 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 ( $\delta \lambda /\lambda $ =7.6%) and the wavelength at the response maximum is $1.08~\mu \text{m}$ 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 $1.08~\mu \text{m}$ at 77 K, corresponding to the responsivity of 0.21 A/W. The resistance–area product at zero bias, $R_{0}A$ , is $1.7\times 10^{7}~\Omega \cdot $ cm 2 at 77 K and is $121~\Omega \,\cdot $ cm 2 at 300K. The Johnson noise limited detectivity ${D^{*}}$ of the device is $1.1\times 10^{13}$ Jones for the wavelength of $1.08~\mu \text{m}$ at 77 K.