多元稀土六硼化物LaxCe1-xB6微观结构及电子发射机理研究

项目名称： 多元稀土六硼化物LaxCe1-xB6微观结构及电子发射机理研究

项目编号： No.51302129

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 一般工业技术

项目作者： 包黎红

作者单位： 内蒙古师范大学

项目金额： 25万元

中文摘要： 对二元稀土六硼化物LaB6添加Ce元素可有效地降低逸出功，同时提高发射电流密度，但其发射机理尚不明确。根据我们前期研究发现，逸出功与阴极材料微观结构密切相关。因此，本项目采用同步辐射XAFS技术辨别La和Ce原子在晶格中的占位，确定吸收原子周边的微观结构及其电子态，并采用密度泛函第一性原理计算每个晶面的逸出功，系统地研究掺杂元素对逸出功的影响规律，探明微观结构与物理性能的内在联系，揭示其发射机理。从而挑出逸出功最低的晶面，制备出高场发射因子的阵列并测定其发射性能。本项目从理论上给出微观结构与物理性能的内在联系，在应用上为平板场发射显示屏提供优良工质材料。

中文关键词： 稀土六硼化物；电子发射机理；第一性原理；；

英文摘要： Doping the Ce elements into binary hexaborides of LaB6 can effectively reduce the work function and improve the emission current density.However, the electronic emission mechanism has not been clear yet.According to our previous study, the work function is related to the microstructure of hexaborides. Therefore, the XAFS technique is used to distinguish the occupation of La, Ce atoms in the crystal and determine the micro-information and electronic state of absorption atoms. On the basis of above studies, the density functional theory using ab intio calculation is used to calculate the work function of each crystal plane and carried out a systematic study on the effects of doping elements on work function. Meanwhile,the internal relationship between the microstructure and the physical properties are established for building up the emission mechanism. Based on above mechanism, the compositions with low work function are chosen for preparing the field emission arrays with high-field enhancement factor. This project can provide the relationship of microstructure with physical properties in theory, which also provide an excellent material for field emission flat display.

英文关键词： rare-earth hexaborides；electronic emission mechanism；first-principles calculations；；