Abstract
The on-surface synthesis of graphene nanoribbons (GNRs) allows for the fabrication of atomically precise narrow GNRs. Despite their exceptional properties which can be tuned by ribbon width and edge structure, significant challenges remain for GNR processing and characterization. Herein, Raman spectroscopy is used to characterize different types of GNRs on their growth substrate and track their quality upon substrate transfer. A Raman-optimized (RO) device substrate and an optimized mapping approach are presented that allow for the acquisition of high-resolution Raman spectra, achieving enhancement factors as high as 120 with respect to signals measured on standard SiO2/Si substrates. This approach is well suited to routinely monitor the geometry-dependent low-frequency modes of GNRs. In particular, the radial breathing-like mode (RBLM) and the shear-like mode (SLM) for 5-, 7-, and 9-atom-wide armchair GNRs (AGNRs) are tracked and their frequencies are compared with first-principles calculations.
| Original language | English |
|---|---|
| Article number | 1900343 |
| Journal | Physica Status Solidi (B) Basic Research |
| Volume | 256 |
| Issue number | 12 |
| DOIs | |
| State | Published - Dec 1 2019 |
Funding
This work was supported by the Swiss National Science Foundation under grant no. 20PC21_155644, the European Union's Horizon 2020 research and innovation program under grant agreement no. 785219 (Graphene Flagship Core 2), the Office of Naval Research (N00014‐18‐1‐2708), and the NCCR MARVEL funded by the Swiss National Science Foundation (51NF40‐182892). Raman scattering modeling used resources at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. Part of the computations was performed using resources of the Center for Computational Innovation at Rensselaer Polytechnic Institute. X.Y.W., T.D., A.N., and K.M. acknowledge the support by the Max Planck Society. This work was partially funded by the FET open project QuIET (no. 767187). M.L.P. acknowledges funding by the EMPAPOSTDOCS‐II program, which is financed by the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska‐Curie grant agreement no. 754364. J.O. and O.B. acknowledge the technical support from the Binning and Rohrer Nanotechnology Center (BRNC); J.O. and M.C. thank Erwin Hack for ellipsometry measurements and fruitful discussions; and Sascha Martin and Heinz Breitenstein for technical support. This work was supported by the Swiss National Science Foundation under grant no. 20PC21_155644, the European Union's Horizon 2020 research and innovation program under grant agreement no. 785219 (Graphene Flagship Core 2), the Office of Naval Research (N00014-18-1-2708), and the NCCR MARVEL funded by the Swiss National Science Foundation (51NF40-182892). Raman scattering modeling used resources at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. Part of the computations was performed using resources of the Center for Computational Innovation at Rensselaer Polytechnic Institute. X.Y.W., T.D., A.N., and K.M. acknowledge the support by the Max Planck Society. This work was partially funded by the FET open project QuIET (no. 767187). M.L.P. acknowledges funding by the EMPAPOSTDOCS-II program, which is financed by the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement no. 754364. J.O. and O.B. acknowledge the technical support from the Binning and Rohrer Nanotechnology Center (BRNC); J.O. and M.C. thank Erwin Hack for ellipsometry measurements and fruitful discussions; and Sascha Martin and Heinz Breitenstein for technical support.
Keywords
- Raman spectroscopy
- Raman-optimized substrates
- graphene nanoribbons
- substrate transfer
- vibrational modes