基于石墨烯与硫化钼功能器件的理论设计及输运性质研究

Due to their novel physical and chemical properties, new 2-dimensional crystalline materials (such as graphene, "white graphene" h-BN, Bi(2)Se(3), MoS(2)) are promising to be used to develop new nanoelectronic and optoelectronic functional devices. This project aims to carry out the computational design and the study of transport properties based on graphene and MoS(2) functional devices. It includes: 1. Intrinsic electrical properties are investigated by using first-principles electronic structure and quantum transport methods, and the influences of doping, defects, ripple/wrinkle and chemical adsorption on the electrical properties and transport performance of double-layer graphene and single-layer MoS(2) are mainly discussed. 2. Novel graphene-based and MoS(2)-based nanoelectronic functional devices (such as semiconductor heterostructures, field-effect transistor, photoelectric conversion devices, etc.) are constructed by material calculation and device design, and the structure-activity relationship between material structure and device performance is established. 3. Graphene-MoS(2) based heterostructures are synthesized experimentally to construct the photoelectric devices, and the corresponding electrical properties and the transport process of carriers are investigated, their application in the field of photoelectric conversion energy devices is also explored. This study is expected to not only help to understand the intrinsic electrical properties and transport micro-mechanisn of graphene and MoS(2), but also design and fabricate several new graphene and MoS(2) based functional devices.

因新颖的物化性质，以石墨烯(Graphene)与硫化钼(MoS2)为代表的二维晶体材料可望用来发展新型纳电子和光电功能器件。本项目旨在开展基于石墨烯与硫化钼功能器件的理论设计与电学输运性质研究，包括：1.运用第一性原理电子结构和量子输运计算方法，研究石墨烯与硫化钼材料的本征电学性质，重点探讨掺杂、缺陷、起伏褶皱与化学吸附对双层石墨烯和单层硫化钼电学性质及输运性能的影响；2.基于材料计算与器件设计，理论设计一系列基于石墨烯与硫化钼的新型功能器件(包括半导体异质结、场效应晶体管、光电转化器件等)，建立材料结构与器件性能之间的构效关系；3.实验制备基于石墨烯-硫化钼材料的纳米异质结构，构筑结构器件，表征电学性质，研究载流子输运过程，并探索在光电转化能源器件领域中的应用。本项目有助于理解石墨烯和硫化钼材料的本征电学性质及输运微观机制，有望理论设计和实验制备出基于石墨烯和硫化钼的新型功能器件。

二维材料与器件是一个科学内涵丰富、应用前景广阔的新领域。以石墨烯和硫化钼（MoS2）为代表的二维材料展示了许多新奇行为和优异的物化性质，可用来发展新型的纳电子器件和光电功能器件。本项目主要开展了新型二维材料（MoS2、碲化钼MoTe2、磷烯Phosphorene）的设计、制备与器件研究。重点研究内容包括：1.运用第一性原理电子结构和量子输运计算方法，研究MoS2、MoTe2、Phosphorene的本征电学与光学性质，发现边缘氢化和纳米带宽度改变等方式可对其电子结构及磁学性质调控，找到了量子反点石墨烯能带带隙闭合的规律；2.基于材料计算与器件设计，理论设计了一系列基于二维材料的新型功能器件(包括半导体异质结、场效应晶体管、自旋电子学器件等)，重点研究电极材料选择、接触方式、杂质、缺陷对器件性能的影响，理论上建立了材料结构与器件性能间的构效关系，基于NbS2-MoS2-NbS2异质结设计的背栅极FETs是双极性输运器件，器件电流开关比为4.7×105，亚阈值斜率为90mV/dec；3.利用化学汽相沉积（CVD）制备方法，制备得到大面积、均匀、高结晶的少数层2H相和1T'相的MoTe2二维材料，发现通过控制钼源可以可控制备不同晶相的碲化钼，在其它生长条件均相同的情况下，三氧化钼为钼源可以得到半导体相的碲化钼（2H相），以金属钼为钼源则制备得到金属相的碲化钼（1T'’相）。本项目揭示了若干新型二维材料的本征光电性质及输运微观机制，理论设计和实验制备出基于此类二材料及其异质结构的新型功能器件，对二维材料的能带工程与器件研究具有重要科学意义。