Structural, electronic and optical properties of Zn1−xZrxO nanotubes: first principles study

First-principles calculations are performed to determine the effects of zirconium doping on structural, electronic and optical properties of zinc oxide nanotubes. Dielectric tensor is derived within the random phase approximation and optical properties are calculated for both parallel and perpendicular electric field polarizations with respect to nanotube axis. Results show that for all impurity concentrations, the formation energy is negative; hence all doped systems are stable. Energy gap of zirconium-doped single walled zinc oxide nanotube is smaller than their pristine zinc oxide nanotube. Our results show that pristine zinc oxide nanotube is a direct gap semiconductor, while it is an indirect gap when zirconium is doped into zinc oxide nanotube. In Zn1−xZrxOs, the absorption edge has red shift to that of pure zinc oxide nanotube and is located at the visible region. Our results show optical anisotropy of pristine and zirconium-doped zinc oxide nanotube.