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 ͑QDIP͒ having distinct sensitivity to mutually orthogonal in-plane polarized infrared radiation, and applicable to practical infrared ͑IR͒ 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 m.

The Emission Directionality of Electronic Intraband Transitions in Stacked Quantum Dots

“…[6][7][8][9]. In addition, since infrared intraband transitions in quantum well devices are forbidden for light polarized perpendicular to the growth direction (normal incident light), QD-based systems are better suited for infrared sensors (IR photo detectors) [10][11][12][13][14][15], low-threshold terahertz vertical-cavity surfaceemitting lasers [16,17], and photovoltaic [18][19][20][21]. In contrast to the polarization of interband transitions in single and stacked QDs (see, e.g., Refs.…”