This Faculty Early Career Development (CAREER) grant provides funding to conduct a detailed study on a novel nanotomy (nanoscale cutting) process to produce graphene quantum dots (GQDs) of well-defined size (10-100 nm), shape (square, rectangle, and triangle), and chemistry (pristine and functionalized); and to thoroughly characterize their structural, optical and electrical properties and property-correlations. By controllably scaling down graphene into nanosized GQDs, its properties can be tuned over a wide spectrum, thus significantly broadening the scope of its applications. In this project, nanotomy of graphite and its subsequent exfoliation will be employed to produce large-quantities of monodisperse GQDs with controlled structure and chemistry. This will be followed by: (a) thorough characterization of the nanotomy-process to determine the GQD size distribution, shape consistency, functionalization density, edge smoothness, defect types and density, crystallography, and nanotomy characteristics; (b) detailed optical and electrical characterization (band-gap; net carrier mobility and density, and carrier transport mechanism in GQD films); and (c) establishing the correlations and theoretical models defining the GQD properties. The results from the correlations and models will be analyzed to further engineer the nanotomy process to fine-tune GQDs' properties.
Development of production-routes and fundamental property-correlations of important nanomaterials have revolutionized nanotechnology. However, synthesis and experimental characterization of GQDs have been a challenge. If successful, the results of this research will develop a novel route to produce well-defined GQDs and uncover their fundamental properties. The models and correlations established will enable direct tuning of GQD properties and rational design of its applications for the semiconductor industry. GQDs could potentially have the same impact that other carbon-nanomaterials have had. Further, the research activities will be integrated with various educational efforts. Nanoprocessing concepts will be incorporated into engineering education at Kansas State University to strengthen its nanotechnology base; new nanoprocessing and nanotechnology activities will be added to university outreach programs designed to improve participation of women/underrepresented students in engineering; and the students will be exposed to diverse research cultures to broaden their perspective on the scope of science.
