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Professor Jeremy Robinson, *Naval Research Laboratory

Event Date: 
Monday, February 26, 2018 - 3:30pm to 4:30pm

Hybridized Graphene Materials

The field of layered two-dimensional (2D) crystals captures an impressively broad range of condensed matter physics phenomena, which exists in the various metal, semiconductor, and insulating forms of atomically-thin 2D van der Waals layers. The exceptional crystalline quality, high mobility, and field-effect properties of graphene have launched an intensive effort to uncover and seek out ‘winners’ that might compliment or replace conventional 3D counterpart materials in new or existing technologies. The rapid development in the synthesis and manipulation of 2D crystals has greatly expanded opportunities for interfacing their unique properties with historically incompatible material systems. In this talk, I will give an overview of the development of graphene and 2D materials and describe specific efforts at the Naval Research Laboratory in manipulating graphene for applications ranging from chemical sensing to nanomechanical resonators. Analogous to other electronic materials, defects are a tool to engineer graphene's properties and tune its response to various stimuli.

I will present results using chemically modified graphene to not only improve chemical sensing, but also achieve new functionality for electronic systems. In particular, we hybridize graphene via the addition of fluorine atoms [1] and show the subsequent formation of nanoribbons and tunnel barriers exploiting property changes from the fluorine adsorbates. Second, I will present results on the electronic hybridization of stacked graphene layers, where the moiré pattern formed by the relative twist between layers is responsible for new properties of the bilayer system [2,5]. Defects specific to this system include rotational disorder, strain, and chemical doping [3]. These defects modify, but do not destroy the strong interlayer coupling. Finally, I will present results on the influence of chemistry and defects on the properties of graphene nanomechanical systems. By measuring the response of high-quality nanomechanical resonators, we can extract relevant mechanical properties including tension, yield strength, resilience, and modulus as a function of defect introduction [4].

Jeremy Robinson is a Materials Research Scientist at the US Naval Research Laboratory (NRL) in Washington, DC. He earned his BS degree in Physics from Towson University and MS/PhD in Materials Science and Engineering from UC Berkeley. In 2007 he was awarded a National Research Council postdoctoral fellowship at NRL, where his postdoctoral work focused on implementing graphene oxide in sensing applications and quickly expanded to widely studying the chemical, electronic and mechanical properties of graphene. He joined the full-time staff in 2008 and continues to focus on the science and technology of 2D materials. He has published over 100 journal articles and his work has been recognized by several awards, including the Sigma Xi Young Investigator Award, and the Presidential Early Career Award for Scientists and Engineers.

Event Location: 
McMaster
Location Details: 
ABB 165