Integration of Graphene as a Work-Function-Tunable Electrode Material with Atomically Thin Layered Transition-Metal-Dichalcogenides

技术说明：本项目的目标是研究石墨烯作为原子级薄层过渡金属二硫属化物（TMD）的功函数可调电极材料，并系统研究石墨烯/TMD接触的电场效应调谐以及TMD沟道在低阻欧姆接触极限下的本征电荷输运特性。为了实现研究目标，主要研究者计划1）制备具有石墨烯电极的原子级薄的半导体TMD材料和器件; 2）通过原子力显微镜、拉曼光谱和电输运测量表征石墨烯/TMD结; 3）使用超大电容离子液体门研究石墨烯/TMD接触的肖特基势垒可调性; 4）研究了低阻欧姆接触极限下TMD沟道的电学特性：5）研究了六方氮化硼封装TMD的最终材料和器件性能;以及6）研究缺陷的性质和密度的影响，和/或或杂质对最终材料和器件性能的影响。非技术描述：该项目的目的是建立一个基本的理解原子薄层状过渡金属二硫属化物作为低功率数字电子通道材料的固有性能极限。这个项目的更广泛的影响是通过紧密结合研究，研究生和本科生教育，社区外展工作完成的。从研究石墨烯/TMD接触的电场效应可调谐性以及TMD作为沟道材料的本征材料和器件特性中获得的知识将有助于为基于TMD的电子学铺平道路。教育方案的重点是促进多样性和招收代表性不足的少数民族学生。综合推广计划预计将加强底特律公立学校的物理科学教育，并提高学生上大学的准备。

Technical Description: The goal of this project is to investigate graphene as a work-function tunable electrode material for atomically thin layered transition-metal-dichalcogenides (TMDs), and to systematically study the electric-field-effect tuning of the graphene/TMD contacts as well as the intrinsic charge transport properties of the TMD channel in the limit of low-resistance Ohmic contacts. To accomplish the research goal, the principle investigator plans to 1) fabricate atomically thin semiconducting TMD materials and devices with graphene electrodes; 2) characterize the graphene/TMD junction by atomic force microscopy, Raman spectroscopy, and electrical transport measurement; 3) study the Schottky barrier tunability of graphene/TMD contacts using an extremely-large-capacitance ionic liquid gate; 4) investigate the electrical properties of the TMD channel in the limit of low-resistance Ohmic contacts; 5) study the ultimate materials and device performance of hexagonal boron nitride encapsulated TMDs; and 6) investigate the influence of the nature and density of the defects and/or impurities in the starting TMD crystals on the ultimate materials and device performance by combined scanning tunneling microscopy/spectroscopy and transport measurements.Non-technical Description: The project aims to establish a fundamental understanding of the intrinsic performance limit of atomically thin layered transition-metal-dichalcogenides as channel materials for low power digital electronics. The broader impact of this project is accomplished by tightly integrating research, graduate and undergraduate education, and community outreach efforts. The knowledge gained from studying the electric-field-effect tunability of the graphene/TMD contacts and intrinsic materials and device properties of TMDs as channel materials will help to pave the way for TMD-based electronics. The emphasis of the education program is placed on promoting diversity and recruiting underrepresented minority students. The integrated outreach program is expected to enhance the physical science education in Detroit public schools and to improve the preparedness of students for college.