Electronic structure transformation from a quantum-dot to a quantum-wire system: Photoluminescence decay and polarization of colloidal CdSe quantum rods

Radiative lifetime, polarization, and the global Stokes shift of colloidal CdSe quantum rods with aspect ratios from 1.9 to 3.8 are measured at room temperature. The radiative lifetime and the global Stokes shift show nonmonotonous dependence on the aspect ratio of the nanorods, and strong linear polarization in emission sharply appears as the aspect ratio crosses a turning point. The features of radiative lifetime and polarization versus aspect ratio in these nanorods indicate a transformation of the electronic structure from a zero-dimensional quantum-dot system to a one-dimensional quantum-wire system. (C) 2002 American Institute of Physics.