二维过渡金属硫化物的光电子特性及其外场调控

The investigations of physical properties in novel materials play a key role in the applications of new-type electronic device. In this proposal, two-dimensional layered transition metal dichalcogenides (TMDs) MX2 ( M is a transition metal element, X is a chalcogen element) and its alloys will be selected as the research target. Using the Raman spectroscopy, photoluminescence spectroscopy, spectroscopic ellipsometry, and infrared magneto-optic spectroscopy, the methods related external field (temperature, electric, and magnetic field) manipulation on the optoelectronic properties of two-dimensional TMDs will be established. The relationship among electronic band structures, dielectric functions, optical band gap of the materials and the number of layer, temperature, magnetic field will be obtained. Based on the lattice vibrations and photoluminescence properties of TMDs under different layers and external field, the physical origins of phonon-electron coupling and optoelectronic transitions will be discussed. Furthermore, the research techniques for optoelectronic properties will be developed. Using the interaction between polarized light and electron polarization orientation, the coupling law among excitonic transition effects, electron polarization and spin effects and the magnetic field, temperature will be explored. The theoretical method for dielectric response analysis will be developed. The physical mechanisms related external field manipulation on the optoelectronic properties in two-dimensional TMDs will be explained. Our research results will provide an experimental evidence and theoretical support for the applications of electronic devices based on two-dimensional TMDs.

研究材料的基本物理特性是推动新型电子器件应用的基础。本项目以新型二维层状过渡金属硫化物MX2(M为过渡金属，X为硫族元素)及其掺杂材料作为研究体系。通过采用拉曼、光致发光、椭圆偏振和红外磁光光谱等多种凝聚态光谱技术，建立外场(温度场、电场和磁场等)对二维过渡金属硫化物光电子特性的调控方法。系统研究该体系的微观电子能带结构、介电函数和光学带隙等性质与材料层数、温度场和电场之间的依赖关系。通过温度场调控不同层数硫化物的晶格振动和光致发光特性，澄清其声子-电子耦合和光电跃迁的物理起源。发展变温和变磁场下的光电评价手段，通过偏振光与电荷极化取向的耦合，探索材料激子跃迁、电荷极化和自旋等效应与外加磁场和温度场的耦合规律。发展介电响应理论分析方法，合理解释外场调控二维过渡金属硫化物光电子特性的物理机理，为基于二维过渡金属硫化物的电子器件的应用提供实验依据和理论支持。

二维过渡金属硫化物由于具有原子级平整、高迁移率和良好光电响应特性等特点有望在电子和光电子器件领域实现应用。因此，非常有必要深入了解二维过渡金属硫化物在温度场、光场和电场等外场作用下的介电函数、光学带隙和电子能带结构等基本物理性质。本项目系统研究了S掺杂对GaSe1-xSx晶体电子能带结构、光学常数、电子跃迁、吸收系数和光学带隙的调控作用，以及少层ReS2薄膜拉曼声子模式、光学常数、电子跃迁、吸收系数、光学带隙和电子能带结构与温度的依赖关系。分析了不同厚度InSe半导体的拉曼声子模式及其放置时间和电场依赖关系，进一步研制了基于二维层状半导体(PbSnS2、InSe和BP/MoS2)的新型电子器件并研究其物理特性与电场耦合规律。在本项目资助下，项目组共发表标注项目资助号的SCI检索论文12篇(其中，中科院一区7篇，二区5篇，期刊影响因子大于10的论文5篇)，包括3篇Advanced Materials, 1篇ACS Nano和1篇Advanced Functional Materials。已申请国家发明专利8项，应邀参加国际国内重要学术会议6次。这些研究成果为基于二维层状过渡金属硫化物的光电子器件和电子器件的应用提供实验依据和理论支持。