Theoretical study on electronic and electrical properties of nanostructural ZnO

The electronic and electrical properties of ZnO semiconductor single wall nanotube were investigated using periodic supercell approach within density functional theory combined with tight-binding quantum chemistry method. Armchair (10, 10) and zigzag (10, 0) nanotubes were considered. The lower strain energies required to roll up a ZnO graphitic sheet into a tube and the negative cohesive energies implied the possibility for the formation of ZnO single wall nanotubes. It was shown that the band gaps between the valence band maximum (VBM) and conduction band minimum (CBM) of nanotubes calculated by means of the two methods are similar and are larger than that of the bulk ZnO. It was found that the band gaps of ZnO nanotube are relatively insensitive to the chirality and diameter. According to the estimated electrical conductivities, the nondefect bulk and nanotube ZnO exhibited insulator properties, while they exhibited semiconductor properties when oxygen vacancies are introduced in the structures. The relative stability and band gap of fullerene-like ZnO clusters were also analyzed.