Structural, electronic and optical properties of Zn1-xSrxO nanotubes: First principles study

First-principles calculations have been performed to determine the effects of Sr doping on the structural, electronic, and optical properties of ZnONT. The dielectric tensor is derived within the random phase approximation (RPA), and optical properties are calculated for both parallel and perpendicular electric field polarizations to the nanotube axis. It is found that all doped systems are exothermic and stable, but by increasing Sr-doping concentration the formation energy increased. The semiconducting energy gap of Sr-doped single walled ZnONT is bigger than their pristine ZnONT. From the optical property calculations, strong absorptions have been found in the visible-light region for both pristine ZnONT and Sr-doped ZnONT. By increasing concentration of Sr-doped the main absorption edge has a further blue shift to that of pure ZnONT. (C) 2013 Elsevier Ltd. All rights reserved.