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本文采用Mossbauer谱和PAT寿命谱对纳米SnO_2进行研究。结果表明,纳米SnO_2的界面相和在真空环境处理造成的氧缺陷,使Sn~(4+)的离子特征下降,改变了样品的超精细结构参数。根据正电子在表面缺陷湮没的两种不同机制,分析了捕获缺陷的类型及其浓度的变化情况。实验表明,纳米SnO_2晶界缺陷处Sn原子附近的电子密度较大,结构中的氧缺陷使电子密度进一步增大。
In this paper, Mossbauer spectrum and PAT lifetime spectrum of nano-SnO_2 were studied. The results show that the interfacial phase of nanostructured SnO_2 and the oxygen deficiency caused by the treatment in vacuum environment decrease the ion characteristic of Sn 4+ and change the ultrafine structural parameters of the sample. According to two different mechanisms of positron annihilation on surface defects, the types of capture defects and their concentration changes were analyzed. The experimental results show that the electron density near the Sn atom in the grain boundary defects of nanostructured SnO 2 is larger and the oxygen vacancy in the structure further increases the electron density.