Hung Chih-Cheng, Lin Wen-Tai, Wu Kuen-Hsien
Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan 701.
J Nanosci Nanotechnol. 2011 Dec;11(12):11190-4. doi: 10.1166/jnn.2011.4057.
The growth of porous ZnO nanowires (NWs) via phase transformation of ZnS NWs at 500-850 degrees C in air was studied. The ZnS NWs were first synthesized by thermal evaporation of ZnS powder at 1100 degrees C in Ar. On subsequent annealing at 500 degrees C in air, discrete ZnO epilayers formed on the surface of ZnS NWs. At 600 degrees C, polycrystalline ZnO and the crack along the (0001) interface between the ZnO epilayer and ZnS NW were observed. At 700-750 degrees C ZnS NWs transformed to ZnO NWs, meanwhile nanopores and interfacial cracks were observed in the ZnO NWs. Two factors, the evaporation of SO2 and SO3 and the stress induced by the incompatible structure at the interface of ZnO epilayer and ZnS NW, can be responsible for the formation of porous ZnO NWs from ZnS NW templates on annealing at 700-750 degrees C in air. Rapid growth of ZnO at 850 degrees C could heal the pores and cracks and thus resulted in the well-crystallized ZnO NWs.
研究了在空气中500 - 850℃下通过ZnS纳米线的相变生长多孔ZnO纳米线（NWs）。ZnS NWs首先通过在1100℃的Ar气氛中热蒸发ZnS粉末合成。随后在空气中500℃退火时，在ZnS NWs表面形成离散的ZnO外延层。在600℃时，观察到多晶ZnO以及沿ZnO外延层与ZnS NW之间的（0001）界面的裂纹。在700 - 750℃时，ZnS NWs转变为ZnO NWs，同时在ZnO NWs中观察到纳米孔和界面裂纹。在空气中700 - 750℃退火时，由ZnS NW模板形成多孔ZnO NWs的原因有两个：SO2和SO3的蒸发以及ZnO外延层与ZnS NW界面处不相容结构引起的应力。在850℃时ZnO的快速生长可以修复孔隙和裂纹，从而得到结晶良好的ZnO NWs。
