Theoretical Study on Band Alignment Mechanism for the ZnO@ZnS Interface of Core-Shell Structures

Abstract

The band alignment mechanism for the ZnO/ZnS interface features of ZnO@ZnS core-shell structures was investigated by Density Functional Theory (DFT) calculations, using a Gaussian-type basis set and periodic boundary conditions. This study leads to an improved understanding of the unique properties of such core-shell structures, especially at the nanoscale. The band structures, energy gaps, electron charge density maps, and density of states for the ordered and disordered models were studied in order to predict the band alignment mechanism and cluster-tocluster charge transfer properties in the ZnO@ZnS core-shell structures with different degrees of crystallinity. The theoretical results show that the type-II behavior of the core-shell structures may provide an in-depth understanding of the close relationship between different coordination environments and structural characteristics, and may also reveal changes in the electronic and structural properties, which occur mainly at their interface. Keywords: Band offset, core@shell, DFT, heterostructure, ZnO, ZnS.