Photodetection around 10 μm wavelength using s-p transitions in InAs/AlAs/AlGaAs self-assembled quantum dots

Abstract

We propose a quantum dot infrared photodetector (QDIP) having distinct sensitivity to mutually orthogonal in-plane polarized infrared radiation, and applicable to practical infrared (IR) imaging applications. Our QDIP has either an InAs/AlAs/AlGaAs or an AlAs/InAs/AlAs/AlGaAs structure in which extra-thin AlAs layers were introduced underneath the AlGaAs buffer layer to strongly confine the carriers and also to enhance the dot density before the Stranski–Krastanov mode growth of InAs quantum dots was carried out. At 80 K, the detector has high sensitivity to in-plane orthogonally polarized infrared light, and photocurrent responsivity peaks of up to 230 mA/W associated with distinct mutually orthogonal polar lights which were observed at a wavelength of around 10.0 μm.