Sensitive quantum-dot infrared detector with barrier-limited photoelectron capture

A wide range of novel properties, unattainable in bulk materials, is now being realized through manipulation of the doping level and length scales associated with quantum-dot structures. One of most promising applications of these structures is a quantum dot infrared photodetector (QDIP). Due to the atom-like localized electronic states, QDIPs ideally have advantages over quantum wells such as sensitivity to the normal incidence radiation, higher photoconductive gain and low dark current. Initial experiments have already shown the advantages of QDIPs over quantum well structures. At the same time, the operating regimes of QDIPs are still very far from optimum. To design a sensitive QDIP with a comparatively high operating temperature, we investigate a structure with QDs surrounded by repulsive potential barriers.