负能隙可调新型半金属探索：结构设计、薄膜生长与物性研究

项目名称： 负能隙可调新型半金属探索：结构设计、薄膜生长与物性研究

项目编号： No.11474335

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 曹则贤

作者单位： 中国科学院物理研究所

项目金额： 102万元

中文摘要： 半金属和零带隙半导体很稀有，这限制了它们在器件中的应用。在固体原有晶格以外开辟新格点的掺杂方式，能对固体的电子结构造成根本性的改变，提供了实现和调节负能隙的新途径。Mn3N、Cu3N具有反ReO3结构，选择合适的额外金属原子占据母体立方晶胞原先为空的中心位置，可以实现固体能隙的大范围调节，获得系列的新型零带隙半导体和负能隙可调半金属。本项目拟采用共溅射法、脉冲电子束烧蚀法和等离子体辅助原子层沉积法获得Mn3NMx, Cu3NMx 基(M=Mn,Cu,Ag,Pd,Zn等）零带隙半导体和能隙可调半金属薄膜，确定能隙对组分的依赖关系，研究该体系固体的半导体-半金属相变、电阻温度系数、输运行为、外场响应等性质，找寻表现负微分电阻的体系、激子型绝缘体及磁性半金属；研究负能隙可调多层膜结构的光电、光热转换，半金属层对隧道结隧穿电流的增强效应，并综合考虑该类固体的特殊物理性质，设计新的半导体-半金属器件

中文关键词： 凝聚态物理；负能隙可调半金属；半导体-半金属相变；薄膜生长；激子型绝缘体

英文摘要： Semimetals and gapless semiconducgtors are quite rare. This fact imposes a strong constraint on the implementation of such materials. To exploit the new lattice sites in addition to the lattice of the original matrix is a particular way of doping, which can radically modify the electronic structure of the solids, it thus holds the promise to give rise to a series of novel gapless semiconductors and semimetals of a tunable negative band gap. The nitride Mn3N and Cu3N are a solid of the anti-ReO3 structure. By properly choosing some extra atoms to occupy the cell centers of the original cubic lattice, which are previously unoccupied, it is possible to alter the band gap to a very large extent that in these series of ternary solids one can find some gapless semicondutors and also semimetals of a tunable negative band gap. With the current project, we intend to grow Mn3NMx and Cu3NMx (M= Mn, Cu，Ag, Pd,Zn,etc.) thin films by using reactive cosputtering, pulsed electron deposition and nitrogen plasma -assisted atomic layer deposition, to search for gapless semiconductors and semimetals of tunable negative band gap. The composition depdence of bandgap will be determined, the semiconductor-semimetal transition, the temperature coefficient of resistance, the (magnetic) transport behavior, and the response to externally applied fields will be investigated, aiming at particularly finding out novel excitonic insulator, magnetic semimetals and also structures that showing negative differential resistance. The photoelectric and photothermal transition of the multilayers of wide tunable bandgaps of the Mn3NMx and Cu3NMx based solids, the tunneling enhancement effect of such a semimetal layer in the tunneling junction will be measured. Finally, on the overall evaluation of the properties in those solids, some semiconductor-semimetal devices based on new working principles will be conceived and tested.

英文关键词： Condensed matter physics;Semimetal of tunable band gap;Semiconductor-semimetal transition;Thin film growth;Excitonic insulator