Pushing Detection Wavelength Toward <inline-formula> <tex-math notation="LaTeX">$1~\mu \text{m}$ </tex-math> </inline-formula> by Type II InAs/GaAsSb Superlattices With AlSb Insertion Layers

Abstract

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, R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> A, is 1.7×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> Ω·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 77 K and is 121 Ω · cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 300K. The Johnson noise limited detectivity D* of the device is 1.1×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</sup> Jones for the wavelength of 1.08 μm at 77 K.