Atomically Precise Graphene Nanoribbon Device Structures
Abstract
Title: Atomically Precise Graphene Nanoribbon Device StructuresObjective: To explore the feasibility of integrating prefabricated graphene nanoribbons (GNRs) with silicon and h-BN surfaces. PI will also apply the tip-based fabrication methods to modify prefabricated GNRs. The goalshere are to create combined GNR heterostructuresthat would be difficult or impossible to fabricate by other methods, as well as to optimize making contactsto GNRsApproach:This project will merge two approaches for fabricating atomically precise graphene nanoribbons (GNRs) with the goal of creating nanoscale device structures. The first approach is to use electrons from a scanning tunneling microscope tip to drive the two-step process of converting halogenated polyaromatic hydrocarbon molecules into GNRs. The first step is to stimulatedehalogenation, which will enable the molecules to covalently link into polymers. This will be followed by electron stimulated dehydrogenation to condense the polymers into finished GNRs.The other approach is to work with prefabricated GNRs that have been synthesized in the group of Prof. Alexander Sinitskii at the University of Nebraska. Initial experiments have shown that we can deposit these GNRs onto atomically clean hydrogen passivated silicon surfaces under ultrahigh vacuum conditions. Furthermore, STM spectroscopy has elucidated subtle variations in GNR electronic structure between the center and edge of the GNR and due to interactions withthe substrates. Experiments will be performed on a wide range of GNRs to determine their atomistic level electronic properties. These GNRs will also be manipulated into configurations suitable for devices and circuits.SOW: Specific research tasks include:1. Optimize the tip-based debromination step of GNR systhesis to achieve single molecule length precision as well as surface orientation control. These experimentswill be performed on Au(111) surfaces in UHV.2. Develop the dehydrogenation process to convert the debrominated polymers into fully formed GNRs. Also, tip-based GNR fabrication will be explored for silicon and h-BN surfaces.3. Develop methods to covalently link GNR precursor molecules to the sides and ends of existing GNRs. This will lead to the formation of metallic end contactsand the formation of GNR-GNR heterostructures.4. Perform STM/STS experiments on straight, chevron, nitride-edge and holey GNRs fabricated by Alexander Sinitskii~s group. Begin experiments on placingGNRs on h-BN.5. Integrate GNRs with h-BN.6. Combine tip-based GNR synthesis and modification with prefabricated GNRs.7. Use nanometallization with HfB2 to contact GNRs. Develop robust nanomanipulation capability for GNRs.8. Fabricate nanoscale GNR FET structures.9. Fabricate circuits that incorporate several GNRs.Merits and ONR Relevance:GNR-based nanoelectronics have the potential to scale well beyond the limits of conventional silicon technology. Atomically precise edge structures and large semiconducting bandgaps suggest the possibility of high-performance GNR transistors and logic circuits. The proposed program addresses the length control, surfaced placement and orientation, and the ability to integrate GNRs with technologically relevant substrates such as silicon and h-BN. GNR-based electronicsare also expected to be inherently radiation hard, thus making them well suited for future high performance applications in naval platforms.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 23, 2016
- Source ID
- N000141613151
Entities
People
- Joseph W Lyding
Organizations
- Office of Naval Research
- United States Navy
- University of Illinois Urbana–Champaign