ZnO nanowires (NWs) were synthesized on
Au-coated Si (100) substrates by vapor transport method.
The effect of high temperature annealing on the structural
and chemical composition as well as thermal stability was
studied. The as-prepared ZnO NWs was nearly stoichiometric
and identified as hexagonal ZnO phase. After
annealing at 1,473 K, the atomic ratio of O/Zn, the intensity
of the diffraction peaks, and the diameter of nanowires
were increased. The ZnO NWs were fragmented into
nanocrystals and the fragments coalesced with each other
after annealing at 1,673 K. The thermal stability of ZnO
NWs was studied by thermo-gravimetric (TG) analysis. A
sharp increase in the TG curves was observed and can be
attributed to the oxidation of some possibly presented Zn
atoms. The activation energy of oxidation of Zn interstitial
atoms was found to be 484.81 kJ mol-1. A mass gain peak
was observed after annealing at 1,473 K, but it was completely
eliminated after annealing at 1,673 K.