US EPA

6392530 

Journal Article 

Semiconductor-conductor transition of pristine polymer-derived ceramics SiC pyrolyzed at temperature range from 1200 degrees C to 1800 degrees C 

Chowdhury, M; Wang, K; Jia, Y; Xu, C 

2020 

Yes 

Journal of the American Ceramic Society
ISSN: 0002-7820 

WILEY 

HOBOKEN 

103 

4 

2630-2642 

10.1111/jace.16961 

WOS:000504315800001 

https://onlinelibrary.wiley.com/doi/abs/10.1111/jace.16961
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This paper studies the effect of pyrolysis temperature on the semiconductor-conductor transition of pristine polymer-derived ceramic silicon carbide (PDC SiC). A comprehensive study of microstructural evolution and conduction mechanism of PDC SiC pyrolyzed at the temperature range of 1200 degrees C-1800 degrees C is presented. At relatively lower pyrolysis temperatures (1200 degrees C-1600 degrees C), the carbon phase goes through a microstructural evolution from amorphous carbon to nanocrystalline carbon. The PDC SiC samples behave as a semiconductor and the electron transport is governed by the band tail hopping (BTH) mechanism in low pyrolysis temperature (1300 degrees C); by a mixed mechanism driven by band tail hopping and tunneling at intermediate temperature (1500 degrees C). At higher pyrolysis temperatures (1700 degrees C-1800 degrees C), a percolative network of continuous turbostratic carbon is formed up along the grain boundary of the crystallized SiC. The samples demonstrate metal-like conductive response and their resistivity increases monotonically with the increasing measuring temperature. 

metal-like conduction mechanism; pristine polymer derived ceramics; semiconductor-conductor transition; turbostratic carbon