Mid-Infrared InAs Photodetector Grown on GaAs Substrate Through Cation Exchange

We report a mid-infrared InAs p-i-n photodetector grown on GaAs using an abrupt method through cation exchange at the InAs/GaAs interface, which has resulted in an extremely thin buffer layer. The InAs p-i-n photodetector has a photoresponsivity of 0.327 A/W at λ = 2.71 μm, which was comparable with the mid-infrared photodetector grown using a compositionally linear-graded process. This result showed that the abrupt method can be used to achieve mid-infrared photodetection on GaAs without the need of a compositionally graded buffer layer.