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.
