| AVS 61st International Symposium & Exhibition | |
| Plasma Science and Technology | Thursday Sessions |
| Session PS-ThA |
| Session: | Plasma Processing of Nanoparticles and Nanomaterials |
| Presenter: | Lorenzo Mangolini, University of California, Riverside |
| Correspondent: | Click to Email |
Despite being heavily utilized in industry, the unique capabilities of non-thermal plasmas with respect of materials processing have yet to be fully realized. In this talk we will describe our effort in understanding the nucleation and growth of silicon nanoparticles in non-thermal plasmas and we will discuss their application for energy-related applications.
Several research groups have focused on nanoparticle nucleation and growth in silane-containing plasmas. Yet a clear understanding of the correlation between plasma parameters and the properties of silicon particles is missing. There is no theory explaining how a non-thermal process can produce nanocrystals of a material with a relatively high melting point within few milliseconds of reaction time. We have performed in-situ FTIR measurements and aerodynamically extracted particles along the length of a flow-through reactor similar to the one described in [1], and have found that silane is rapidly consumed and converted into amorphous particles with size close to their final one. Crystallization takes place after the precursor is fully consumed and within few milliseconds. An independent measurement of the crystallization rate of small silicon particles [2] suggests that their crystallization kinetics exceeds that of bulk amorphous silicon films. Despite this the current models describing the plasma-nanoparticle interaction [3,4] cannot justify the substantial heating necessary to achieve crystallization in such short time. Results from our ongoing efforts in this area will be presented.
By leveraging the processing capabilities of non-thermal plasmas it is possible to provide improvements in the performance of devices that are relevant for energy-related applications. By sintering plasma-produced nanocrystals it is possible to fabricate bulk samples with precise control of grain size and grain size distribution. These samples show some of the lowest thermal conductivities ever reported for the case of bulk nanostructured silicon. This is a promising step towards the development of highly efficient waste-heat recovering devices that do not require alloying with expensive materials such as germanium. Furthermore, plasma-produced silicon particles can also be integrated into anodes for lithium-ion batteries. Their excellent dispersibility into polymer matrices allows achieving stable operation over hundreds of charge-discharge cycles.
[1] L. Mangolini et al., Nano Letters 5 (2005) 655.
[2] T. Lopez and L. Mangolini, Nanoscale 6 (2014) 1286.
[3] L. Mangolini and U. Kortshagen, Physical Review E 79 (2009) 026405.
[4] N. J. Kramer et al., Journal of Physics D: Applied Physics 47 (2014) 075202.