电子能谱仪中能量分析器的沾污及其消除方法

本文阐述了电子能谱仪的关键部件——电子能量分析器的一种慢性故障现象(沾污)及其消除方法。着重地描述和讨论了分析器沾污对能谱仪工作的影响以及导致产生慢性故障的原因和症结——分析器减速栅极带电。利用辉光放电的方法对分析器减速栅极进行了清洗,使谱仪恢复到正常工作状态,效果显著。     

CaF_2/Si(111)界面的电子结构和化学键(英文)

CaF_2/Si(111) interfaces formed at 700℃ as well as at room temperature have been studied with XPS, UPS and LEED. The experimental results show that the substrate temperature has a significant influence on the interface in respect of ifs electronic structure and chemical bond. When the substrate temperature was at 700℃, the interface is found to be consisted of predominate Si-Ca bonds which correspond to an interface state located at 1.2eV below Fermi level. There is depletion of fluorine atoms due to the dissociation of the CaF2 molecule at the interface. When the substrate was at room temperature, there are no chemical bonds between substrate and adatoms nor depletion of fluorine atoms at the interface. Annealing of this interface at 700℃ results in preferential evaporation of F, and the surface undergoes a number of reconstructions until a 3×1 reconstruction is obtained. The bonding at this interface is similar to that of CaF2/Si(111) interface when the substrate temperature was at 700℃.