Effect of pressure and Al doping on structural and optical properties of ZnO nanowires synthesized by chemical vapor deposition

The effect of Al doping concentration and oxygen ambient pressure on the structural and optical properties of chemical vapor deposition-grown, Al-doped ZnO nanowires is studied. As Al doping increases, the strength of the broad visible emission band decreases and the UV emission increases, but the growth rate depends on the oxygen pressure in a complex manner. Together, these behaviors suggest that Al doping is effective in reducing the number of oxygen vacancies responsible for visible emission, especially at low oxygen ambient pressure. The intensities and quantum efficiencies of these emission mechanisms are discussed in terms of the effect growth and doping conditions have on the underlying excitonic decay mechanisms.