Theoretical Studies of Electronic and Optical Properties of Nanocrystal Quantum Dots and Ordered Nanocrystal Solids
Naval Research Laboratory, DC, Materials Science & Technology
We study the dynamical optical characteristics of II-VI semiconductor nanocrystals, including radiative recombination times, transition oscillator strengths, nonradiative Auger recombination times, thermalization times of nonequilibrium carriers, and spin relaxation times. Competition between these processes is a strong function of crystal radius and determines the photoluminescence quantum efficiency. We investigate the polarization properties of the luminescence of an assembly of nonspherical crystals and characterize their shape and orientation distributions. We also study spin-spin contact interactions of electrons and holes, as well as their interaction with the spins of nuclei and magnetic ions in different types of quantum dots. We investigate band formation and transport properties of ordered nanocrystal solids and are working on binary nanocrystal solids. Close contact with experiment and collaboration with experimental researchers is maintained.