Size-dependent strain effects on electronic and optical properties of ZnO nanowires

The electronic and optical properties of ZnO nanowires under uniaxial strain are investigated using first-principles calculations. The results show that the electronic band gap for the ultrathin ZnO nanowires displays a nonmonotonic relationship with the strain, while the gap is inversely proportional to strain and shows a linear relationship for the nanowires with diameter larger than 2.4 nm. Optical properties calculations show that the dielectric function peaks for ultrathin nanowires display a redshift with decreasing uniaxial strain, this energy shift decreases with increasing diameter and vanishes as the diameter increases to 2.4 nm. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3464974]