Fabrication and growth mechanism of zinc blende and wurtzite CdTe nanowire arrays with different photoelectric properties

Abstract

Large-scale, well-aligned CdTe nanowire arrays with different crystallographic phases have been prepared simply by regulating the basic growth parameters of the sputtering method. Pure zinc blende phase nanowire arrays that propagate in the (111) direction are achieved using a high growth temperature coupled with a low deposition rate. Conversely, wurtzite phase nanowire arrays with growth in the (002) direction have also been prepared by using a lower growth temperature and higher deposition rate. A Gibbs free energy nucleation model is use to explain the formation of these different crystal phases under the growth conditions employed. The differences in crystal structure are shown to exhibit different energy bands, defects and carrier transport properties. The wurtzite phase, with a narrower band gap (1.64 eV), is found to have better photoelectric properties than those of the zinc blende phase.