Influence of ZnSe core on the structural and optical properties of ZnSe/ZnS core/shell nanocrystals: Tight-binding theory

• The structural and optical properties of ZnSe/ZnS core/shell nanocrystals are sensitive with ZnSe core diameters.
• The reduction of the single-particle and excitonic gaps is a sign of the quantum confinement effect.
• The radiative lifetimes are increased with the increasing core diameters, making the lower photoluminescence quantum yield.
• Good agreement is found with the available experimental data.

I report an atomistic tight-binding model on ZnSe/ZnS core/shell nanocrystals of experimentally associated sizes. Based on the single-particle states computed by tight-binding theory, the excitonic states, atomistic characters, carrier overlaps, radiative lifetimes, and oscillation strengths are simulated, compared, and analyzed as a function of core diameters. The efficient manipulation of electronic structures and optical properties is practically achieved by changing core sizes. In addition, simulations using tight-binding theory successfully show a good concordance with experimental data. According to the observed results, the knowledge of core formation on the structural and optical properties of ZnSe/ZnS core/shell nanocrystals will be inductive in the fabrication of various optoelectronic devices.