二维过渡金属硫化物畴界缺陷研究

Two-dimensional(2D) transition metal dichalcogenides (TMDs), with many novel properties, are excellent candidates for both fundamental research and commercial applications. But their application still faces a number of scientific and technological issues，such as the synthesis of high quality 2D material, the improvement of mobility. The existence of defects such as domain boundary and antisite is inevitable during the preparation of material. These defects, together with the surface/interface scattering, will directly affect the carrier mobility and result in a lower performance. Based on MBE growth，we shall probe physical mechanism of domain boundary and phase transition in as-grown TMDs. More specifically, the structural identity and vital condition of the defects in as-grown TMD epifilms will firstly be investigated by density functional theory. The aim is to not only understand the defects but also contain them in order to improve the quality of the samples. Second, the structural stability and electronic structures of the latest ML-TMDs will be investigated. In addition to the magnetic and carrier mobility effects brought about by substrates and defects/dopants, others such as electric field and adsorption effects will be followed as well. Thirdly，the advantages of these materials for senser and catalysis and the different routes available to tune their electronic states and active sites will be discussed. We also explore the future opportunities of these catalytic materials and the challenges they face in terms of both fundamental understanding and the development of industrial applications. This research will expectedly generate results of great scientific and practical value for future exploration of the materials in device applications.

二维过渡金属硫族化合物(TMDs)具有许多优异的性能，要实现广泛的应用还有许多诸如高质量材料的合成、迁移率的提高等问题需要解决。在材料的制备过程中不可避免的会出现畴界、反位等缺陷，它们与表面/界面散射一起会直接影响载流子的迁移率，导致器件性能的降低。针对这些问题，本项目结合实验从理论上首先对二维TMDs材料中出现畴界、发生相变的机理进行系统研究，找到控制生长的关键要素，促进材料质量的提高；其次，研究新体系的稳定性、电子结构和出现的新特性，探讨衬底、杂质、电场及吸附对原子/电子结构、自旋和输运性质的影响，找到相应的调制方式；在此基础上进一步研究畴界和缺陷在敏感和催化等领域的应用基础，从电子层次探寻其敏感和催化性能的微观机理。通过该项目研究，会对不同ML-TMDs体系的特性有更深入的认识，以期实现对结构和电子性质的精确控制，为二维TMDs制备和应用提供理论依据。

丰富的电子性质使得基于ML-TMDs的层状材料在电子、光电子器件和催化方面具有较大的应用前景。本项目从理论上分别对过渡金属硫族化合物（TMDs）(如：MoS2, MoTe2, WS2, WSe2)、Te稀、石墨烯、BC3、Ga2O3等二维材料的结构特性开展较全面的研究工作。计算了本征缺陷、界面（同质与异质）体系的原子结构、电子结构及磁性；研究了电场、压强等调控方式对体系的原子、电子结构和磁性大小的影响。研究非金属原子包裹Fe原子核壳结构镶嵌在石墨烯体系的电子结构特性，并对原子修饰石墨烯、TMD体系对多种气体分子表现出的气敏特性进行研究。分别对过渡金属硫族化合物（TMD）、石墨烯、石墨炔等新型二维材料的结构和掺杂性能开展研究。随着研究的深入进展和新的研究人员的参与，对原有的地研究内容进行了扩展，对石墨烯、石墨炔等体系进行了较系统地研究，探讨了通过原子掺杂的调控方式对体系的原子、电子结构和磁性大小的影响；比较了不同修饰的石墨烯和石墨炔体系的催化过程，为类石墨烯复合材料的功能性和应用前景提供了重要理论依据。课题组成员围绕课题的中心内容开展研究工作，在国际学术期刊上发表研究论文80余篇；同时，通过课题的研究极大地促进了青年教师科研能力的提升，培养了多名硕士、博士研究生。圆满完成工作任务，相关的后续研究工作还会进行更深入的进行。