Optical Properties of Bulk and Nanocrystalline Cadmium Telluride

Abstract

We have given an overview of the optical properties of bulkand nanocrystalline cadmium telluride in connection with theunderlying electron and phonon states and we have shown howthese states in CdTe QDs are related to their bulk counterparts.From the theoretical viewpoint, it is an exemplary QD material.Because of the large exciton Bohr radius, the electrons and holes inthese dots are in the strong confinement regime, with the excitonlifetime of the order of tens of nanoseconds [66]. The valenceand conduction bands of CdTe are offset from those of CdSe andCdS, so that it is possible to prepare type-II core/shell NCs fromcombinations of these materials. Thanks to the cubic crystalstructure and direct bandgap of the material, the QD exciton andphonon states can be described by simple models and it makestheir control easier.