二维材料中单个缺陷的电输运研究

A variety of intrinsic or man-made defects introduced in two-dimensional materials are important mediators in controlling their optoelectronic properties. In electrical, optical, energy and other applications, defects have an important influence on the conductivity of two-dimensional materials / electrodes, two-dimensional materials / catalysts, two-dimensional material heterojunctions and other interfaces. We plan to conduct in-depth basic research on the electrical transport behavior of single defects in two-dimensional materials through this project. We will mainly use conductive atomic force microscopy to measure the electrical transport properties of various types of single defects, including point defects, grain boundaries, edges, etc. in 2D materials such as graphene and single-layer transition metal sulfides. Combined with atomic structure characterization and density functional theory calculations, the electrical transport behavior of a single defect of two-dimensional material is understood from the atomic and electronic structure levels. We systematically use the various types of tip material and tip morphology of the AFM to widely simulate and study the electrical contact interface in practical applications of 2D materials for various types of intrinsic defects, chemical modified defects and molecular decorated defects. Finally, we will use experimentally derived/theoretically optimized interface/defect structure to prepare the real electronic devices, to verify the single defect electric transport results. At the same time through this project we also strive to improve the conditions of conductive atomic force microscopy, breaking the existing limit of spatial resolution.

二维材料内各种本征或者人为引入的缺陷是调控其光电性质的重要媒介。在电学，光学，能源等各类应用中，缺陷对于二维材料/电极，二维材料/催化剂，二维材料异质结等界面的导电性具有重要影响。我们计划通过本项目对二维材料中单个缺陷的电输运行为进行深入的基础研究。我们将主要利用导电原子力显微镜测量二维材料如石墨烯和单层过渡金属硫化物内，各类单个缺陷包括点缺陷，晶界，边缘等的电输运性质。然后再结合原子结构表征和密度泛函理论计算，从原子和电子结构层次理解二维材料单个缺陷的电输运行为。我们将系统利用原子力显微镜的各类针尖材料以及针尖形貌，针对各类本征缺陷，化学改性缺陷，分子修饰缺陷等，来广泛模拟和研究二维材料实际应用中的电接触界面。最后我们将利用经过实验和理论优化的界面结构和缺陷结构来制备实际电子器件对单个缺陷电输运结果进行验证。同时通过本项目我们也力争改善导电原子力显微成像条件，突破现有的极限空间分辨率。

二维材料内各种本征或者人为引入的缺陷是调控其光电性质的重要媒介。在电学，光学，能源等各类应用中，缺陷对于二维材料/电极，二维材料/催化剂，二维材料异质结等界面的导电性具有重要影响。我们通过本项目对二维材料中单个缺陷的电输运行为进行了深入的基础研究。我们主要利用了导电原子力显微镜和原位透射电镜-导电原子力显微镜测量二维材料如石墨烯和单层过渡金属硫化物内，各类单个缺陷包括点缺陷，晶界，边缘等的电输运性质。然后再结合原子结构表征和密度泛函理论计算，从原子和电子结构层次理解二维材料单个缺陷的电输运行为。我们系统总结并且优化了二维材料的各类本征缺陷，化学改性缺陷，分子修饰缺陷等，来广泛模拟和研究二维材料实际应用中的电接触界面。我们在本项目中实现了对单个原子缺陷的导电性能测试，把原子结构和导电性能在原子尺度联系起来，找到了二维材料电接触性能的优化方案。我们通过直接的点对点接触实验，证明了范德华接触相对于化学接触（或者说缺陷态接触）在二维材料中的优越性，这些研究结果有望对未来的二维电子器件设计带来直接帮助。