| AVS 64th International Symposium & Exhibition | |
| 2D Materials Focus Topic | Friday Sessions |
| Session 2D+MI+NS+SS+TF-FrM |
| Session: | Nanostructures including Heterostructures and Patterning of 2D Materials |
| Presenter: | Ximeng Liu, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign |
| Authors: | X. Liu, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign A. Radocea, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign T. Sun, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign M. Pour, Nebraska Center for Materials and Nanoscience, University of Nebraska - Lincoln N. Aluru, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign A. Sinitskii, Nebraska Center for Materials and Nanoscience, University of Nebraska - Lincoln J.W. Lyding, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign |
| Correspondent: | Click to Email |
Graphene nanoribbons (GNRs) with atomically smooth edges, controllable geometry and therefore tunable electronic band gaps have ignited enormous interest due to their high potential for future electronic devices. Among different techniques for GNR characterization, scanning tunneling microscopy and spectroscopy (STM/STS) provide both topographic details and local electronic structure with atomic resolution. Large-scale production of two different kinds of chevron-type GNRs (the double-wide (w) GNRs and the extended chevron (e) GNRs) was realized by a solution synthesis method [1]. Dry contact transfer technique [2] was implemented for depositing the solution-synthesized GNRs onto clean InAs (110) and hydrogen-passivated Si(100) semiconducting surfaces under ultrahigh vacuum conditions. For both GNRs, their structures were confirmed by high resolution STM imaging. The band gap of the eGNRs was determined to be 2.6eV via STS. For the wGNRs, detailed analysis and mapping of the electronic density of states both spatially and energetically was carried out with STS and current imaging tunneling spectroscopy. We found that the electron orbital shapes at the GNR edges are different from those at the centers, in agreement with computational simulations. The measured band gap of the wGNRs was only 2eV, which may result in a great improvement in conductivity. In addition, these GNRs are found to be transparent to the substrate when scanned at a small tip-sample separation, indicating a strong interaction when GNRs are pushed towards the substrate.
References:
1. Vo, T. H.; Shekhirev, M.; Kunkel, D. A.; Morton, M. D.; Berglund, E.; Kong, L. M.; Wilson, P. M.; Dowben, P. A.; Enders, A.; Sinitskii, A., Large-Scale Solution Synthesis of Narrow Graphene Nanoribbons. Nat. Commun. 2014,5, 3189.
2. Ritter, K. A.; Lyding, J. W. The influence of edge structure on the electronic properties of graphene quantum dots and nanoribbons. Nat. Mater. 2009, 8 (3), 235−42.