Higher excited electronic states in clusters of ZnSe, CdSe, and ZnS: Spin-orbit, vibronic, and relaxation phenomena

Abstract

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.

Structural and optical properties of CdTe/CdSe heterostructure multilayer thin films prepared by physical vapor deposition technique

“…The transitions close to the fundamental band gap (E g ) of II-VI semiconductors arise due to the spin-orbit split of valance band energy levels (Baldereschi and Lipari 1971). Based on the model proposed by Chestnoy et al (1986), the valance band components U 7 v and U 8 v are expected to give rise to one set of discrete hole states separately as depicted in Fig. 6.…”

Spin-Based Quantum Dot Qubits

“…thermodynamic parameters) which influence the SACQDs growth are not well understood and as a result the shape of the SACQDs, which are very important in determining confining energies of electrons/holes, can not be easily achieved with high quality. Semiconductor QDs growth techniques which have been often used are the colloidal methods (Blackburn et al, 2003;Chestnoy et al, 1986;Wang & Herron, 1991) There is not an applied external magnetic field to the structure. and the high-resolution electron lithography.…”

Hollow, Branched and Multifunctional Nanoparticles: Synthesis, Properties and Applications

“…[1][2][3][4][5] In addition to size, shape and structure details (e.g., surface chemistry and porosity) also strongly influence the physical and chemical properties of nanoscale materials. As a result, realizing a precise control over the morphology including size, shape and structure details of nanomaterials has been one of the major goals in nanoscience.…”