- Title
- Synthesis and characterization of high energy milled silicon nanoparticles for electronic applications
- Creator
- Mnguni, Nomvula Bianca
- Subject
- Chemical and Physical Sciences
- Date Issued
- 2023-00
- Date
- 2023-00
- Type
- Masters theses
- Type
- text
- Identifier
- http://hdl.handle.net/11260/9936
- Identifier
- vital:74651
- Description
- This study demonstrates that high energy milling using a planetary disc mill offers a new simple route to the production of polycrystalline silicon nanoparticles which are suitable for electronic applications. By manipulating process variables such as milling duration and mass of the feedstock load, the microstructure of the nanoparticles can be tuned to meet requirements. The internal structure of the nanoparticles prepared by high energy milling was found to predominantly consist of nanocrystalline silicon and their surfaces are characterised by a disordered layer of silicon sub-oxides and an insignificant proportion of fully oxidized silicon. X-ray diffraction (XRD) patterns and Raman spectra were used to calculate the average crystallite size and correlating it to the milling process variables. The surface chemistry of the nanoparticles was elucidated using X-ray photo spectroscopy (XPS) and was also related to the milling parameters. The internal structure, agglomeration and aggregation of the particles were tested using high resolution transmission microscopy (HRTEM) and complemented by scanning electron microscopy (SEM). Conductivity tests were done on the particles to ascertain their suitability for electronic applications. It is demonstrated that the longer the milling time, the smaller the sizes of particles and crystals. The sizes also depended on the mass of feedstock load. 30 g feedstock loads resulted in average nanoparticle size which were 30 - 40 % larger than for 10 g loads. The average size of nanoparticles produced were in the range 50 – 80 nm as measured by SEM. The distribution of the size of particles became less polydisperse with increase in milling time and a reduction in feedstock load. The particles were devoid of significant SiO2 layer and hence were confirmed by conductivity tests to be electrically active. Data from XPS indicate that the silicon nanoparticles have a unique surface chemistry which is consistent with the silicon surfaces being dominantly oxygen terminated.
- Description
- Thesis (Masters) -- Faculty of Commerce and Administration, 2022
- Format
- computer
- Format
- online resource
- Format
- application/pdf
- Format
- 1 online resource (77 pages)
- Format
- Publisher
- Walter Sisulu University
- Publisher
- Faculty of Natural Sciences
- Language
- English
- Rights
- Faculty of Commerce and Administration
- Rights
- All Rights Reserved
- Rights
- Open Access
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | BN Mnguni_MSc in Physics Thesis_final.pdf | 3 MB | Adobe Acrobat PDF | View Details Download |