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Articles you may be interested inElectron ground state energy level determination of ZnSe self-organized quantum dots embedded in ZnS Metal selenide clusters have been made and characterized, using the arrested precipitation colloidal technique. A comparison of sulfide and selenide spectra enables observation of the effect of changes in the highest occupied molecular orbitals upon cluster electronic properties. The first and second excited electronic states are both observed as a function of size in ZnSe clusters. The systematic dependence of the spectra lead to assignment of the higher state to a IS-type hole based upon the split-off valence band. It is shown that the energy spectrum of discrete hole states is controlled by the spin-orbit energy and the isotropic hole mass in small, highly symmetrical clusters. This result contrasts with the heavy hole and light hole states observed for planar confinement. In ~ 20 A diameter ZnS clusters, there is a strong vibronic temperature dependence in the excited state spectra, while in clusters of smaller gap materials such vibronic effects are very minor. We conjecture that lifetime broadening is severe in clusters of small gap materials.

The luminescence of CdS Clusters prepared by arrested precipitation has been studied as function of time, temp., wavelength, and physical size.

As2 dimer molecules generated by evaporating gallium arsenide were trapped and studied in solid neon. Components of at least three different excited electronic states are populated by direct tunable laser excitation and observed in phosphorescence. Nonradiative vibrational and electronic relaxation processes occurring in the matrix have been investigated. The electronic structure and spectroscopy of As2 is reviewed and summarized.