Articles techniques et présentations

This paper showed: * The electronic states of core-shell tetrapod with various shell thickness were calculated. Lowest 20 electron and hole wave functions have A1 or T2 symmetry. * At t=1.2 nm, the carriers separation is not serious, core-shell tetrapod is not apparent type II heterostructure. * Exciton states were investigated as a function of t. For large t, the lowest exciton state has T2 symmetry, which implys nonluminescence in emission spectrum. * Core-shell tetrapod with broken symmetry shows non-zero oscillator strength for lowest exciton state.