氧化锌纳米带的低温无催化热蒸发制备及其表征

通过纯锌粉蒸发，在600 ℃无催化条件下成功制备了高质量的不同形貌的ZnO纳米带.该制备方法中控制产物形貌和尺寸的关键是氧、氩及锌蒸气的流速及分压.扫描电镜及高分辩透射电镜观察显示，氧化锌纳米带具有规整光滑及齿状等不同形貌，且皆为单晶，其生长由固-气机理控制.室温光致发光谱表明，齿状氧化锌纳米带在390 nm附近形成紫外发射峰；在455～495 nm时，形成绿光发射峰，该处由4个次级发射峰组成.

Fabrication, Structures and Optical Property of ZnO Nanobelts Prepared by a Novel Zn-powder Evaporation Technique

Uniform ZnO nanobelts and toothed-nanobelts were synthesized respectively through pure zinc powder evaporation without catalyst at temperature of 600 ℃. In each processing, the total gas flow rate of argon and oxygen was 200～300 cm³?min^－1, and the fraction of oxygen was 1％～5％ according to changes of the conditions. The experiments indicated that the key of the preparation method is to control the flow rates and partial pressures of argon, oxygen, and zinc vapor. The flow rates and partial pressures influenced the size of nanostructures, and more sensitively determined the belts with or without teeth. 　　Scanning electron microscopy (SEM) observations showed that the fabricated ZnO nanobelts had several types in morphology. The high-resolution transmission electron microscopy (HRTEM) images and selected area electron diffraction (SAED) patterns revealed that the ZnO nanobelts were single crystalline. HRTEM images and SAED patterns also suggested that the teeth of the toothed-nanobelts grew along the 0001] or 2110] direction, i. e., the teeth of such belts may grow in “c” or “a” direction, the backbones of the belts may grow in “a” or “c” direction accordingly. X-ray diffraction (XRD) investigations on the structures showed that all the deposited nanobelts on the silicon substrate were pure ZnO with hexagonal wurtzite structure. Investigations through HRTEM and XRD indicated that the growth of ZnO nanobelts was controlled by vapor-solid (VS) mechanism. 　　Photoluminescence(PL) spectrum of ZnO toothed-nanobelts at room temperature was measured and showed a UV emission at ～390 nm and a broad green emission with 4 subordinate peaks at 455～495 nm.