Ab initio study of structural and electronic properties of single crystal and core/shell II-VI semiconductor nanowires

Abstract

Structural and electronic properties of pristine and H-passivated wurtzite type ZnSe, ZnTe nanowires and ZnX/ZnY (X=Se(Te) and Y=Te(Se)) core/shell nanowires oriented along the [0001] direction have been investigated using first-principles calculations. The changes in the electronic structure of the nanowires due to the quantum confinement and morphology have been searched. Quantum confinement increases the band gap energy as the diameters of ZnSe and ZnTe nanowires decrease. Both homostructured and heterostructured nanowires are found to show a semiconducting character with direct band gaps at Γ-point. Changing the morphology from homostructured nanowires to heterostructured core/shell nanowires has an important impact on the electronic structure. For instance, the charge separation of electrons and holes along the infinite direction of core/shell nanowires shows a strong preference for electron(hole) states localized inside ZnSe(ZnTe) regions.