Effect of in situ Al doping on structure and optical properties of ZnO nanowires grown by MOCVD

Al-doped ZnO nanowires (NWs) were grown on C-axis oriented sapphire by metal organic chemical vapor deposition using dimethylzinc–triethylamine (DMZn–TEN), nitrogen dioxide (NO2) and TMAl as zinc, oxygen and aluminum doping sources respectively. The NWs morphology has been characterized by scanning electron microscopy and transmission electron microscopy. The photoluminescence (PL) spectra exhibit a strong excitonic transition bond that confirms the Al incorporation in the ZnO NWs. Raman results support PL conclusion by showing additional modes in Al-doped ZnO NWs at nearly 270, 510, 579 and 641 cm−1. The micro-Raman scattering analysis along a single Al-doped ZnO needle-like NW shows an increase of the Al concentration from the basis to the tip of the wire.