纳米SnO2和SnO2／SiO2材料的正电子湮没研究

采用溶胶一凝胶法制备了纯纳米ＳｎＯ２和掺杂ＳｉＯ２的纳米ＳｎＯ２材料，应用Ｘ射线衍射和正电子湮没寿命谱等手段进行了纳米材料的界面结构和纳米晶粒的生长过程，结果表明，所制备的纳米ＳｎＯ２和ＳｎＯ２／ＳｉＯ２材料中只存在两类缺陷，分别对短寿命τ１和中等寿命τ２，材料中两类缺陷的数量比与粒径有关，纳米ＳｎＯ２晶粒生长随热处理温度升高为分两个阶段，低于晶化临界温度时，晶粒生长缓慢，高于此温度时，则生长迅速

Positron lifetime studies for nanocrystalline SnO2 and SnO2/SiO2

Nanocrystalline SnO2 and SiO2- doped SnO2 samples prepared by the Sol- gel process have been investigated by X- ray diffraction and positron lifetime spectroscopy. lt was shown that only two kinds of defects were found in the interfaces of both samples, i.e.free volumes and microvoids. lt appeared that when the sintering temperature was lower than the crystallization temperature, the grains grew slowly, and above this temperature the growth became faster. Furthermore, grain growth of the pressurized samples was slower than that of the powder. And SiO2 doping effectively restrained the growth of nanocrystalline SnO2 grains,