Electronic structure and optical properties of ZnS/CdS nanoheterostructures

Article

关键词: DOT QUANTUM-WELLS;    CDS/HGS/CDS;    CDSE;    NANOCRYSTALS;    ZNS;   

DOI  :  10.1103/PhysRevB.67.235303

来源: SCIE

【 摘 要 】

The electronic and optical properties of spherical nanoheterostructures are studied within the semiempirical sp(3)s(*) tight-binding model including the spin-orbit interaction. We use a symmetry-based approach previously applied to CdSe and CdTe quantum dots. The complete one-particle spectrum is obtained by using group-theoretical methods. The excitonic eigenstates are then deduced in the configuration-interaction approach by fully taking into account the Coulomb direct and exchange interactions. Here we focus on ZnS/CdS, ZnS/CdS/ZnS, and CdS/ZnS nanocrystals with particular emphasis on recently reported experimental data. The degree of carrier localization in the CdS well layer is analyzed as a function of its thickness. We compute the excitonic fine structure, i.e., the relative intensities of low-energy optical transitions. The calculated values of the absorption gap show a good agreement with the experimental ones. Enhanced resonant photoluminescence Stokes shifts are predicted.

【 授权许可】

Free