The goal of this Faculty Early Career Development (CAREER) project at the Pennsylvania State University is to explore mesoscopic physics in a newly discovered two-dimensional material: graphene. Graphene, a single sheet of carbon atoms arranged in a hexagonal lattice, possesses a set of unusual physical properties which may lead to new physics in two dimensions. A closely-coupled second layer (bilayer graphene) enhances the richness and complexity of the system, providing even more intriguing opportunities. Graphene is also a promising material for high-speed electronics thanks to its highly mobile charge carriers. The uniting theme of this project is to use geometrical, electrical and chemical manipulations of various substrates and adsorbates to modulate and study the electronic properties of single and bilayer graphene. Mesoscopic confinement structures will be created to explore new phenomena arising from graphene's unique band structure, lattice symmetry and spin interactions. The educational component of this project will provide career training for graduate and undergraduate researchers. Research results from the PI's lab and the field of nanoscience will be disseminated to the public through on- and off-campus venues including local libraries and the arts festival. The PI will use her role as a co-coordinator of the Penn State REU program to draw the participation of students from underrepresented groups in this project.
The goal of this Faculty Early Career Development (CAREER) project at the Pennsylvania State University is to explore the electronic properties of a newly discovered two-dimensional material: graphene. Graphene, a single sheet of carbon atoms arranged in a hexagonal lattice, possesses a set of unusual physical properties which may lead to new physics in two dimensions. A closely coupled second layer (bilayer graphene) enhances the richness and complexity of the system, providing even more intriguing opportunities. Graphene is also a promising new material for high-speed electronics thanks to its highly mobile charge carriers. The uniting theme of this project is to create novel structures on the micro- and nano-sale through geometrical, electrical and chemical manipulations of graphene and to explore their electrical transport properties. New device configurations will be developed to take advantage of graphene's excellent electrical properties. The educational component of this project will provide career training for graduate and undergraduate researchers. Research results from the PI's lab and the field of nanoscience will be disseminated to the public through on- and off-campus venues including local libraries and the arts festival. The PI will use her role as a co-coordinator of the Penn State REU program to draw the participation of students from underrepresented groups in this project.
The objectives of this Career Award are to understand the physical properties of graphene, which is an atomically thin sheet of carbon atoms arranged in a honeycomb lattice, and explore means to engineer its property towards the development of miniature, novel electronic devices such as high-speed transistors, memories and biosensors with fast and compact electrical readout. It is envisioned that these basic research may advance the fundamental understanding of materials on the atomic and nanometer scale and enable technological innovations that will benefit the society at large. Our explorations have been fruitful. We have shown that the properties of graphene are significantly influenced by its surroundings so that by controlling the substrates, encapsulations, and chemical elements attached to the sheet, new properties such as memory functionalities, effective cooling of transistors operating at high current, and magnetic properties can be engineered. Two layers of graphene sheets stacked together, i.e. bilayer graphene, possesses properties distinct from the doubling of one layer. We demonstrated the continuous tuning of a band gap, which is an essential element of digital transistors and switches, in bilayer graphene using an electric field. We also synthesized fluorinated graphene, where fluorine atoms are attached to the graphene sheet and this attachment turned graphene from a superb conductor into an electrical insulator. This ultrathin insulator may find its use in circuits built by vertically stacking a family of atomically thin materials together, of which graphene is a member. The research activities and findings enabled by this grant gained significant insights on several aspects of graphene research including understanding and controlling the fundamental charge motion in this excellent electronic material, synthesis of graphene and graphene derived materials and the fabrication of complex electronic devices and understanding their operation principles. Several of these experiments were in collaboration with colleagues from different disciplines (chemistry, materials science) and from different institutions and countries. This program trained 4 PhD students, 2 postdoctoral fellows and provided the opportunities for many undergraduate students from Penn State and other universities to participate in cutting-edge research in nanoscience and nanotechnology. Our lab has also hosted the visits of middle school and high school students in summer science camps and workshop activities to give them hands-on experiences in working in a lab. The PI has participated in numerous panel meetings, roundtable discussions, mixer events to encourage women and underrepresented students to take on science careers.
