Size dependence and spatial variation of electronic structure in nonpolar ZnO nanobelts

Abstract

The enhancement of performance for next-generation optoelectronic devices is determined by how much we understand the size effects on the electronic structure and their spatial variation in low-dimensional nanostructured semiconductors. In this work, the size-dependence and spatial variation of the electronic structure of ZnO nanobelts were investigated with density functional theory and tight-binding model. The result shows that the thickness of the nanobelt exhibits stronger influence than the width on the band gap energy variation with the cross sectional area of the nanobelt larger than 0.75 nm2, which is consistent with the tight-binding modeling. Real space density-of-state mapping demonstrates alternating peaks and valleys due to the presence of 3- and 4-fold bonding sites along the nonpolar nanobelt surface.