热蒸发法制备Zn1-xCdxO纳米管及其生长机制研究

采用热蒸发纯Zn粉和Cd粉, 在湿反应气氛中氧化制备得到掺Cd的ZnO纳米管, 其Cd含量为3.3at%. 场发射扫描电镜(FESEM)及高分辨透射电镜(HRTEM)分析表明, 大部分纳米管外径约80~150nm, 长度达数微米, 壁厚约20nm. 通过与相同条件下制备的ZnO纳米结构的室温光致发光谱(PL) 进行对比发现, 由于Cd的掺入, Zn_1-xCd_xO纳米管的紫外近带边峰(UV NBE)从3.26eV红移到3.20eV附近.分析认为，Zn_1-xCd_xO纳米管遵循气液固(VLS)生长机制, 并在此基础上提出Zn_1-xCd_xO纳米管生长过程, 同时指出Kirkendall效应可能对纳米管的形成起到了重要作用.

Fabrication and Growth Mechanism of Zn1-xCdxO Nanotubes by Thermal Evaporation Method

The Cd-doped ZnO nanotubes with Cd content of about 3.3at% were synthesized via a process of evaporating mixture of pure Zn and Cd powders and then oxidating in a wet condition. Field-emission scanning electron microscope (FESEM) and high resolution transmission electron microscope (HRTEM) analysis indicate that most of the nanotubes are of about 80-150nm in outer diameter, several micrometers in length, and about 20nm in wall thickness. Compared with photoluminescence (PL) spectra of the pure ZnO nanostructures prepared in the same condition, the room-temperature ultra violet (UV) near-band-edge (NBE) emission of the Zn_1-xCd_xO nanotubes exhibite a slight red shift from 3.26eV to 3.20eV, which is attributed to Cd substitution. It is suggested that the growth of the Zn_1-xCd_xO nanotubes follow vapor-liquid-solid (VLS) mechanism, and a possible growth process of the Zn_1-xCd_xO nanotubes is put forward. The Kirkendall effect is considered to play an important role in the formation of the Zn_1-xCd_xO nanotubes.