Electrical conduction mechanism in carbon-ceramic composites

Carbon-ceramic composites (C/Cer) have been prepared by chemical vapor deposition of coal tar pitch onto clay substrates and characterized by thermogravimetric analyses, powder X-ray diffraction, Raman spectroscopy, and scanning and transmission electron microscopies (SEM and TEM). The study of the dc electrical conductivity, together with the determination of the Hall voltage sign, proves that such C/Cer composites are n-type semi-conductors. Our results demonstrate that: 1) the mechanism of electrical conduction of C/Cer semiconductors proceeds through the pathways expected for amorphous solids (ie. variable-range hopping and heat-activated pathways at low and high temperatures, respectively); and 2) their transport properties are strongly depen-dent on the clay components, as evidenced by microscopy experiments.

Automated summary

Carbon-ceramic composites (C/Cer) were prepared by chemical vapor deposition of coal tar pitch onto clay substrates and characterized using various techniques. The study showed that the C/Cer composites are n-type semiconductors and their electrical conduction mechanism follows the expected pathways for amorphous solids. The transport properties of C/Cer composites are strongly dependent on the clay components as observed in microscopy experiments.