WHAT DID THE 2010 EARLY CAREER AWARD ALLOW YOU TO DO?
Graphene, a one-atom thick sheet of carbon, exhibits incredible structural flexibility, electrical transport, and optical responses. And remarkably, the graphene electronic structure can be varied through interlayer coupling, nanoscale patterning, and electrical gating. The novel properties of graphene also led to great interest in other atomically thin two-dimensional materials and their heterostructures, where fascinating new electrical and optical properties can emerge.
My DOE Early Career project focused on understanding and controlling the electronic structure in graphene and other two-dimensional materials by combining advanced device fabrication, electrical control, and laser spectroscopy. Within the Early Career project, we found that gate-tunable insulating state in bilayer graphene represented a quantum valley-Hall insulator and demonstrated topological valley transport at bilayer graphene domain walls. We also demonstrated ultrafast generation of pseudo-magnetic field for valley excitons in WSe2 monolayers and ultrafast charge transfer in atomically thin MoS2/WS2 heterostructures. These studies opened up new ways to control dynamic optical properties in transition metal dichacogenide monolayers and heterostructures with femtosecond time resolution.
The DOE Early Career Award played a critical role in my research career and laid the foundation for our current research activities on electrical and optical properties in two-dimensional van der Waals heterostructures. For example, I successfully established a DOE core program on “Van der Waals Heterostructures: Novel Materials and Emerging Phenomena”, where it relies heavily on the research direction that established through the DOE Early Career Award.
Feng Wang is a Professor in the Department of Physics at the University of California – Berkeley and a faculty scientist at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory.
SUPPORTING THE DOE SC MISSION:
The Early Career Award program provides financial support that is foundational to young scientists, freeing them to focus on executing their research goals. The development of outstanding scientists early in their careers is of paramount importance to the Department of Energy Office of Science. By investing in the next generation of researchers, the Office of Science champions lifelong careers in discovery science.
For more information, please go to Early Career Research Program page.
THE 2010 PROJECT ABSTRACT:
Control Graphene Electronic Structure for Energy Technology
The goal of this research project is to develop a fundamental understanding of the electronic structure and the novel electrical, vibrational, and optical behavior of graphene, a one‐atom thick sheet of carbon that exhibits incredible structural flexibility, electrical transport, and optical properties. This understanding and control would enable the development of a number of novel graphene-based devices that will impact a broad range of energy technologies ranging from thermal energy converters and low power electronics to fuel cells and solar energy harvesting.
L. Ju, Z. Shi, N. Nair, Y. Lv, C. Jin, J. Velasco Jr, C. Ojeda-Aristizabal, H.A. Bechtel, M.C. Martin, A. Zettl, J. Analytis, and F. Wang, “Topological valley transport at bilayer graphene domain walls.” Nature 520, 650-655 (2015). [DOI:10.1038/nature14364]
X. Hong, J. Kim, S. Shi, Y. Zhang, C. Jin, Y. Sun, S. Tongay, J. Wu, Y. Zhang, and F. Wang, “Ultrafast charge transfer in atomically thin MoS2/WS2 heterostructures.” Nature Nanotechnology 9, 682–686 (2014). [DOI:10.1038/nnano.2014.167]
J. Kim, X. Hong, C. Jin, S. Shi, C-Y.S. Chang, M-H. Chiu, L-J. Li, and F. Wang, “Ultrafast generation of pseudo-magnetic field for valley excitons in WSe2 monolayers.” Science 346, 1205-1208 (2014). [DOI:10.1126/science.1258122]
Additional profiles of the 2010 Early Career Award winners can be found at: https://www.energy.gov/science/listings/early-career-program.
The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit https://science.energy.gov.
Sandra Allen McLean is a Communications Specialist in the Office of Science, firstname.lastname@example.org.