Electron dynamics in unoccupied states of spatially aligned 7-a graphene nanoribbons on Au(788)

N. F. Kleimeier, A. Timmer, L. Bignardi, H. Mönig, X. L. Feng, K. Müllen, L. F. Chi, H. Fuchs, and H. Zacharias

Phys. Rev. B 90, 245408 – Published 3 December 2014

Abstract

Bottom-up synthesized armchair graphene nanoribbons with a width of seven C = C bonds (7-aGNRs) have gained widespread interest due to their large band gap of about 2.8 eV and their atomically precise edge structures. Here, we report on the lifetime of excited states of spatially aligned 7-aGNRs grown on a vicinal Au(788) surface. Time-resolved three-photon photoemission spectroscopy at $h ν = 3.15$ eV was carried out to measure the lifetimes of states located at $E_{1} - E_{F} = 3.6$ eV and $E_{2} - E_{F} = 3.8$ eV via a resonant excitation from an unoccupied state at $E - E_{F} = 0.6$ eV. Lifetimes of $τ_{1} = (110 \pm 13)$ fs and $τ_{2} = (75 \pm 10)$ fs are observed, respectively.

Received 3 September 2014
Revised 10 November 2014

DOI:https://doi.org/10.1103/PhysRevB.90.245408

Authors & Affiliations

N. F. Kleimeier^1,*, A. Timmer¹, L. Bignardi¹, H. Mönig¹, X. L. Feng², K. Müllen², L. F. Chi^1,3, H. Fuchs^1,4, and H. Zacharias¹

¹Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm Strasse 10, and Center for Nanotechnology, Heisenbergweg 11, 48149 Münster, Germany
²Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
³Institute of Functional Nano and Soft Materials (FUNSOM) & Collaborative Innovation Center of Suzhou Science and Technology, Soochow University, Suzhou, Jiangsu 215123, People's Republic of China
⁴Institute for Nanotechnology, Karlsruhe Institute of Technology, 76344 Karlsruhe, Germany

^*kleimeier@wwu.de

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Vol. 90, Iss. 24 — 15 December 2014

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