Opto-Electronic Properties and Stability of Artificial Zinc Oxide Molecules

Abstract

ABSTRACTThe Hartree-Fock (HF), restricted open shell HF (ROHF), and multiconfiguration self-consistent field (CI/CASSCF/MCSCF) approximations are used to study computationally the electronic properties of zinc oxide artificial molecules whose structure and composition have been derived from those of the symmetry elements of the wurtzite bulk lattice of zinc oxide. Such molecules may provide realistic models for small ZnO quantum dots (QDs) synthesized in “vacuum” or quantum confinement (such as that of well-defined nanopore arrays of silica and alumina membranes) using variety of methods in particular, supercritical fluid deposition. The computational direct optical transition energy (OTE) of the confined molecule appears to be several times smaller than that of the corresponding vacuum cluster. The charge and spin density distributions of these molecules (CDDs and SDDs, respectively) differ significantly, revealing dramatic effects of quantum confinement on electronic properties of Zn-O clusters. The obtained results suggest that manipulations with the electronic properties of the confined clusters by sophisticated design of their quantum confinement may provide means for synthesis of Zn-O – based electronic materials that combine a wide, tunable band gap with large, tunable exciton binding energy.