Optical properties of epitaxially grown wide bandgap single quantum dots

Abstract

The strength of spatially resolved optical spectroscopy is demonstrated for revealing fascinating optical, electronic and magnetic properties of wide bandgap semiconductor single quantum dots based on II–VI and III-N compounds. Strong carrier confinement and high polarity result in large Coulomb and exchange ener- gies and efficient photon and phonon coupling of excitons, charged excitons and biexcitons. Coherent state control as well as stimulated biexciton emission in in- dividual quantum dots is achieved and superradiance in quantum dot ensembles is demonstrated. As major steps toward nonclassical light emitters, wide bandgap single quantum dots are shown to exhibit high temperature single photon emission as well as room temperature electroluminescence. In II–VI single quantum dots iso- electronically doped with magnetic ions, nanoscale magnetization can be optically probed and manipulated and in the limit of a single magnetic impurity embedded in a quantum dot, even the spin state of an individual magnetic atom in a solid state matrix can be addressed, which might be a promising step toward spin based quantum information processing.