管状ZnO的电化学法构筑及形成机理

ELECTRODEPOSITION AND FORMATION MECHANISM OF ZnO TUBULAR STRUCTURE

采用两步电化学法分别在氧化铟锡(indium-tin oxide,ITO)玻璃基板和经缓冲层处理的ITO玻璃基板上制备ZnO微米管和纳米管。从Zn(NO3)2和六亚甲基四胺水溶液中阴极电沉积制备ZnO柱状晶体。用乙二胺水溶液进行电化学腐蚀。用X射线衍射仪和扫描电镜研究产物的物相和形貌演变,初步探索管状结构的形成机理,结果表明:管状结构由柱状结构中心腐蚀而形成,由柱状演变为喇叭状,再到管状;腐蚀首先发生在亚稳态的(0001)面,主要沿c轴方向进行;同时,从缺陷浓度高的中心向缺陷浓度低的外围进行。退火实验验证了缺陷腐蚀机理。

Zinc oxide （ZnO） microtubes and nanotubes were prepared on indium-tin oxide （ITO） substrates and ZnO buffer layer/ITO substrates respectively by a two-step approach,which involves the electrodeposition of ZnO rods from Zn（NO3）2 and hexamethylenetetramine aqueous solution and subsequently selective dissolution from ethylenediamine aqueous solution to form tubular structure. The phase structure and morphology of ZnO films were investigated by the X-ray diffraction and scanning electron microscope. The results indicate that ZnO rods turn into ZnO trumpets at the beginning of etching,and then develop to ZnO tubes. The formation mechanism of tubular structure is discussed. Firstly,the metastability of （0001） plane leads to preferential etching in （0001） plane. Secondly,the unbalanced distribution of defects in ZnO rods resulted in selective etching in the center of the rods. The annealing experiments testify the formation mechanism.