Shape-induced anisotropy of intraband luminescence from a semiconductor nanocrystal.

Nonspherical semiconductor nanocrystals (NCs) may exhibit strongly anisotropic photoluminescence due to the intraband transitions, whose matrix elements depend critically on the envelope wave functions of the confined electrons and holes. We demonstrate that this anisotropy may be used as the basis for a new type of polarization spectroscopy, enabling one to reliably determine the shape and spatial orientation of individual NCs, as well as providing important information on the symmetry of quantum states involved in optical transitions.