Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 69: Poster Session: II-VI semiconductors; Organic semiconductors; Heterostructures
HL 69.8: Poster
Mittwoch, 13. März 2013, 16:00–20:00, Poster A
Excitons in ZnCdSe/ZnSe quantum dots with parabolic confinement potential — •Tamar Tchelidze1 and Irakli Noselidze2 — 1Iv. Javakhishvili Tbilisi State University , Faculty of Exact and Natural Sciences, 3 Chavchavadze Ave. 0179 Tbilsi, Georgia — 2Rustaveli National Science Foundation , 1 Aleksidze st . Tbilsi, Georgia
Material distribution profile is found to have significant influence on emission properties of quantum structures. It was reported that core/shell ZnCdSe/ZnSe semiconductor nanocrystals individually exhibit continuous, non-blinking photoluminescence, which was explained by softening the abrupt confinement potential of a typical core/shell nanocrystal, suggesting that the structure is a radially graded alloy of CdZnSe into ZnSe(Xiaoyong Wang et al, Nature 459, 686-689, 2009). We present exact calculation of electronic states for spherical core*shell quantum dots with realistic boundary condition: inside the dot potential is taken equal to -ar2, outside the dot - zero. Calculations are carried out for ZnCdSe/ZnSe structure. We use single band effective mass approximation for finding single particle states of electrons and holes. Exciton states with corresponding energies are calculated by direct diagonalization of Hamilton matrix for 8 lowest excitonic states and their radiative decay probability in dependence of quantum dot radius are calculated. We found that for quantum dots with radius less than 8 nm there is no electron levels inside the dot. For this radius exciton binding energy is 56 meV.