铁基磁性超卤素调控二维MoS2载流子及磁性的微观机理研究

Two-dimensional MoS2 is considered to be a very potential two-dimension material since graphene. However, our previous study shows that the electrical conductivity of single layer MoS2 is not strong. The reason may be that the carrier mobility of MoS2 is far lower than that of graphene and even traditional silicon semiconductor. Furthermore, single layer MoS2 is N-type nonmagnetic semiconductor naturally. These limit its application in electron device and diluted magnetic semiconductor. This project concretely aims at the key scientific problems regarding the improvement of the carrier and magnetic properties for two-dimensional MoS2, as well as investigating the internal physical mechanism. The main research contents are as following: Using First-Principles combined with the CALYPSO global structure prediction technique, as well as the chemical vapor deposition, we try to construct the structural model of two-dimensional MoS2, which is modified by magnetic superhalogens Fe(NO3)3,4. The effects of magnetic superhalogens on the carrier, electronic structure and magnetic properties of MoS2 will be investigated theoretically and experimentally. Based on the binding pattern, energy band, deformation potential energy and electron spin density, the intrinsic physical mechanism of making two-dimensional MoS2 exhibit more excellent properties will be investigated. This research will not only establish the theory to describe the regulation of electronic and magnetic properties of MoS2, but also provide theoretical support for application of MoS2 in nano electronic devices and magnetic materials. It has important scientific significance in the development of the cross-science between atomic and molecular physics and material science.

二维MoS2是继石墨烯后又一非常具有潜力的二维材料。然而，我们前期研究表明单层MoS2的导电性不强，原因可能是其载流子迁移率远低于石墨烯甚至传统硅半导体。并且单层MoS2天然呈强N型非磁性半导体，这限制了其在电子器件及稀磁半导体领域的应用。本项目针对调控二维MoS2载流子和磁性，并探究内部物理机理这一重要科学问题展开研究。研究内容包括：结合CALYPSO全局结构预测技术、第一性原理及化学气相沉积法，构建磁性超卤素Fe(NO3)3,4修饰二维MoS2的结构。理论与实验相结合，探究磁性超卤素对MoS2载流子、电子结构及磁性的影响。基于结合方式、能带结构、形变势能和电子自旋密度等角度，探明调控二维MoS2载流子及磁性的物理微观机理。本项目将发展一种描述二维MoS2电磁性质调控的理论方法，为其广泛应用于纳米电子器件及磁性材料提供依据，这对推动原子分子物理和材料科学的交叉发展具有重要意义。

二维MoS2是继石墨烯后又一非常具有潜力的二维材料。然而本征二硫化钼载流子类型单一且迁移率不高，且呈现非磁性，这限制了其在电子器件及稀磁半导体领域的应用。针对此科学问题，本项目采用铁基磁性超卤素调控二维MoS2的载流子和磁性，并探究其内部物理机理。理论方面，基于第一性原理系统研究了铁基磁性超卤素Fe(NO3)3吸附单层MoS2的结构、电子性质和磁性。结果表明，磁性超卤素与MoS2的相互作用较弱，Fe(NO3)3分子应物理吸附在H-MoS2和T’-MoS2上。能带结构、态密度和差分电荷密度表明，单层H-MoS2和Fe(NO3)3的电子态几乎不会相互影响，而各自保持它们的独立性。但是Fe(NO3)3的吸附可以给T’-MoS2引入~0.24eV的杂质带隙。有趣的是，H相MoS2吸附Fe(NO3)3后具有5μB的磁矩。相比之下，T′相MoS2吸附后的磁矩相对较小(0.95-3.20 μB)。此外，Fe(NO3)3吸附还可以有效地调节MoS2的迁移率，尤其是对H-MoS2的调控。实验方面，采用氧化钼和硫粉为前驱物，制备了大尺寸高品质单层二硫化钼。整个晶畴区域表现出了高的单晶性以及低的缺陷密度。基于单个晶畴MoS2阵列的FET器件，表现出优异的性能。这些结果为调控单层MoS2的电子性质和磁性提供了理论参考，有可能促进其在下一代功能电子器件中的应用。. 基于相关研究成果我们共发表SCI论文9篇，授权国家发明专利1件。论文发表在《ACS Nano》、《Chemistry of Materials》、《Journal of Physical Chemistry Letter》、《Inorganic Chemistry》、《Molecular Physics》等SCI期刊。项目组三名研究生直接参与课题研究，两名负责二维MoS2吸附结构的构建，以及数据处理。另一名研究生开展单层二硫化钼CVD制备的相关工作。 三名研究生均已顺利取得硕士学位。. 我们已圆满完成所有预期成果和目标。