''Atomic and electronic structure of bottom-up synthesized graphene nanoribbons characterized via non-contact atomic force microscopy and scanning tunneling microscopy'' Shiyong Wang

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Date:   Monday, January 26^th, 2015

Time:   10:00-11:00

Venue:  D015, Lab1

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Speaker:

Dr. Shiyong Wang

Empa, Swiss Federal Laboratories for Materials Science and Technology

Dübendorf, Switzerland

Title:

Atomic and electronic structure of bottom-up synthesized graphene nanoribbons characterized via non-contact atomic force microscopy and scanning tunneling microscopy

Abstract:

Atomically precise graphene nanoribbons (GNR) represent a conceptually new class of materials that, by quantum confinement and edge effects, exhibit a bandgap that is of particularly importance in electronic applications. Taking advantage of the newly developed on-surface GNR fabrication method, state-of-the-art nc-AFM techniques and STM manipulations, we thoroughly investigated three different on-surface synthesized GNRs: armchair GNRs of width N=7, armchair GNRs of width N=14, and chevron GNRs.

High-resolution nc-AFM is used to directly resolve the chemical bonds within GNRs. This is achieved by picking up a single CO molecule on the apex of Qplus tip. The detailed electronic structure of GNRs is investigated via scanning tunneling spectroscopy and STM manipulations. The results unambiguously answer some of the fundamental debates of graphene nanoribbons, e.g., the value of fundamental bandgap, spin splitting of magnetic Tamm edge states, etc.

Biography:

Dr. Shiyong Wang took his Ph.D study at the Hong Kong University of Science and Technology from 2009 to 2013. After that, he moved to Swiss Federal Laboratories for Materials Science and Technology as a Postdoc researcher. His research focuses on on-surface synthesis and characterization of organic materials using low temperature STM/STS, nc-AFM, and STM manipulations. He is the author of 15 papers in peer reviewed journals.  

Host:

Prof. Yabing Qi