Dimensional transition and carrier dynamics in Cd_xZn_1−xTe/ZnTe nanostructures on Si substrates

Abstract

We investigate the dimensional transition and carrier dynamics in CdxZn(1-x)Te/ZnTe nanostructures with various Cd mole fractions, grown on Si substrates. Atomic force microscopy images show that the dimensional transition from quantum dots (QDs) to quantum wires occurs with increasing Cd mole fraction. The activation energy of the electrons confined in CdxZn(1-x)Te QDs with a Cd mole fraction of 0.6 is higher than that of electrons confined in CdxZn(1-x)Te nanostructures. In addition, the radiative recombination rate shows a linear dependence on the length of the CdxZn(1-x)Te nanostructures, which is well explained in terms of the "coherence volume" of the bound excitons. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4705413]