| AVS 65th International Symposium & Exhibition | |
| Plasma Science and Technology Division | Friday Sessions |
| Session PS-FrM |
| Session: | Plasma Modeling |
| Presenter: | Devin Coleman, University California, Riverside |
| Authors: | D. Coleman, University California, Riverside A. Hosseini, University of California, Riverside A. Greaney, University of California, Riverside S. Bux, Jet Propulsion Laboratory, California Institute of Technology J.P. Fleurial, Jet Propulsion Laboratory, California Institute of Technology L. Mangolini, University of California, Riverside |
| Correspondent: | Click to Email |
Beta phase silicon carbide nanoparticles are produced by a two step non-thermal plasma process. The surface morphology of the particles is tunable from bare silicon carbide, and between monolayers or few-layers of graphitic or "graphene-like" shells
The bare silicon carbide particles are used as an additive for bulk n-type silicon thermoelectrics. Silicon carbide is mixed with silicon nanopowders, produced by high energy ball milling, and the composite is consolidated by conventional hot pressing into bulk pucks. 99+% density is achieved at volume fractions ranging from 0-5% silicon carbide in silicon. The addition of these nanoinclusions results in a modest decrease in both electrical and thermal conductivities. Most notably, there is also an enhancement in the magnitude of the Seebeck coefficient by up to 40%, resulting in an 80% improvement of the figure of merit, ZT, compared to the parent silicon. This effect is modeled as an energy filtering process, courtesy of Prof. Alex Greaney and his student Aria Hosseini.
The particles with graphene-like shells exhibit a broadband IR absorbance as measured by ATR-FTIR. The peak position, width, and intensity varies as a function of particle size, shell thickness, and surface coverage. A similar phenomenon has been predicted in computational work by F. Abajo for free-standing graphene structures. The computational results show narrow absorbance peaks, compared to broad features in the experimental. This is attributed to a distribution in shell size and number of layers. Additionally, Raman characterization of as-produced powders yields spectra most similar to "damaged" or "defective" graphene. A comparison of previous works, experimental results, and FDTD modeling using Lumerical software will be presented.