CAREER: Tailoring Properties of Graphene by Modifying its Environment

Vanderbilt University, Nashville TN

Investigators

Abstract

*** Non-Technical Abstract *** Graphene, a single atomic layer of graphite, is a recently discovered material that conducts electricity better than copper, has mechanical strength greater than steel, and can be patterned into structures smaller than a virus. Due to this unique combination of properties, graphene has been hailed as a possible replacement of silicon in electronic devices. Because graphene is very conductive, electronic components made of graphene are expected to be able to operate at very high speeds while dissipating very little energy. This award supports a project that experimentally explores the fundamental reasons limiting the conductivity of graphene. In particular, this project examines how the materials near the graphene surface influence the flow of electrons in graphene. The project utilizes a combination of state-of-the-art techniques to fabricate graphene devices with nanometer dimensions and to measure the properties of these devices at low temperatures and in high magnetic fields. If successful, the project will pave the road to both designing appropriate substrates for graphene-based electronics and to creating novel graphene based devices. An integral part of this research project is to introduce underrepresented minorities into the cutting edge scientific research through the partnership with Fisk University, a historically black university. The PhD students engaged in this work will gain hands-on experience and skills in forefront scientific research that are highly valuable in careers ranging from academia to the semiconducting industry. *** Technical Abstract *** Because of the two-dimensional nature of graphene, its electronic and magnetic properties sensitively depend on its environment -- the substrate under the graphene, the impurities near it, and the material coating its surface. This dependence influences many of the fundamental properties of graphene, such as its minimum conductivity, and determines the material parameters, such as carrier mobility, essential for device applications. This project explores the influence of the environment on the electronic and magnetic properties of graphene by placing it onto different substrates and depositing different materials onto its surface. To understand the intrinsic electronic properties of graphene, pristine suspended graphene devices will be fabricated and the electronic transport properties of these devices will be measured at low temperature and at high magnetic fields. To elucidate the role of the charge and spin scattering due to the environment, the transport properties of suspended graphene covered with controllably deposited impurities will be studied. The project also examines the possibility of inducing magnetism in graphene by depositing magnetic materials over it and by depositing graphene onto corrugated substrates. The project supports education of graduate students pursuing a doctoral degree and includes an integrated outreach plan that introduces underrepresented minorities as well as undergraduate students into graduate level research.