Jonathan D. Ambrose Torres - University of Puerto Rico, Mayaguez
Co-Author(s): Hua Hong, Rutgers, State University of New Jersey, New Brunswick Stephen D. Tse, State University of New Jersey, New Brunswick
Research in graphene constitutes a major field in nanotechnology; It is a single atomic layer of a hexagonal carbon network. Graphene has world record breaking properties such as electrical mobility: Hence, applications in renewable energy for complex electronics such as super-capacitors for the next electric car ‘battery’ or lithium anode replacement in batteries for longer storage capacities and nontoxic disposal. Moreover, to mass produce single layer graphene economically, researchers have considered Chemical Vapor Deposition (CVD). Most researchers use low pressure CVD, and some use CVD at ambient pressure. Although, ambient pressure CVD yields faster growth, it is still costly since air is vacuumed and a buffer gas –to add pressure- is injected into the camber. Both LP&APCVD require a chamber, electricity to heat the substrate, and gas sources. However Tse’s research group has devised a single step method of graphene synthesis, using a multi-elemental diffusion flame burner in an open environment at ambient pressure. Furthermore, flame synthesis is advantageous compared to CVD because of its scalability for large-area surface coverage, increased growth rates, high purity and yield, continuous process, and reduced cost (since fuel is used as both heat source and reagent for graphene growth). The gas ratios, growth times, and post annealing times are used as controls to synthesize monolayer and bi-layer graphene. Raman spectroscopy data exemplifies this by the characteristic G peak to 2D peak intensity ratio of 1:1. Note a 1cm x 1cm sheet of graphene is grown in under 30 minutes, compared to LP&APCVD growth which requires one to seral hours.
Currently, graphene is being doped with Nitrogen for functionalized purposes in transistors. This group attempted Nitrogen doping using Methane as fuel and N₂ and NH₄OH as precursors for N-graphene. The precursor/carrier gases were employed during growth and post annealing times as controls, respectively. Raman spectroscopy peak ratios of 1:2 prove bilayer graphene can be growth and we hypothesize single can be easily grown too. SEM/EDS was used to assess the presence of Nitrogen in graphene, however, further changes in parameters are required to obtain sound results. In all, the following was concluded: The experimental set-up can grow pristine single and bi- layer graphene using Ar, N₂, and NH₄OH as the carrier gases. Additional parameters are being examined to dope N better into the graphene lattice.
Funder Acknowledgement(s): I thank Dr. Tse, his research group, and my mentor Hua Hong for their guidance: Dr. Tse, again, for funding of Raman and SEM/EDS tests. Dr. ChennualtCook for encouragement and formation in scientific communication. GET-UP scholar peers for criticism. The Nation Science foundation under grant #1263250.
Faculty Advisor: Stephen D. Tse,