Structural characterization of annealed Si{sub 1-x}C{sub x}/SiC multilayers targeting formation of Si nanocrystals in a SiC matrix
- ARC Photovoltaics Centre of Excellence, University of New South Wales, Sydney, New South Wales 2052 (Australia)
Amorphous Si{sub 1-x}C{sub x}/SiC multilayer films were prepared by alternating deposition of Si-rich Si{sub 1-x}C{sub x} and near-stoichiometric SiC layers by using magnetron sputtering. The as-deposited films were annealed at different temperatures (T{sub a}) from 800 to 1100 deg. C. The influence of T{sub a} and Si content in the Si-rich layer on the layered structural stability and on the formation of Si and/or SiC nanocrystals (NCs) is investigated by a variety of analytical techniques, including x-ray reflectivity (XRR), x-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, and Fourier transform infrared spectrometry (FTIR). XRR showed that Si{sub 1-x}C{sub x}/SiC multilayers annealed at temperatures of up to 800 deg. C retain their layered structure. XRD revealed that Si NCs were formed in samples with a high Si content in the Si-rich layer for T{sub a}{>=}800 deg. C. At annealing temperatures of 900 deg. C or greater, the formation of Si NCs was accompanied by the formation of {beta}-SiC NCs. Additionally, the formation of Si and SiC NCs was confirmed by TEM imaging and Raman spectroscopy. The Si-NC size obtained from the TEM micrographs is within the range of 3-5 nm. The {beta}-SiC NCs are smaller (2-3 nm) than Si NCs. Raman analysis identified an {approx}9 cm{sup -1} Raman peak shift in the Si-NC peak to a lower energy with respect to that for bulk Si. FTIR Si-C bond absorption spectra exhibited narrowing of the full width at half maximum and a peak shift toward a higher wave number with increasing T{sub a}. This behavior can be explained by an increase in order as well as an increase in the number of Si-C bonds.
- OSTI ID:
- 21137164
- Journal Information:
- Journal of Applied Physics, Vol. 103, Issue 8; Other Information: DOI: 10.1063/1.2909913; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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