Changes on the Surface of the SiO<sub>2</sub>/C Composite, Leading to the Formation of Conductive Carbon Structures with Complex Nature of DC Conductivity

Sol–gel layers have been the subject of many studies in recent decades. However, very little information exists about layers in which carbon structures are developed in situ. Using the spin-coating method, we obtained thin iron-doped SiO<sub>2</sub>/C composite films. The results of Rama...

Full description

Bibliographic Details
Main Authors: Piotr Okoczuk, Marcin Łapiński, Tadeusz Miruszewski, Piotr Kupracz, Leszek Wicikowski
Format: Article
Language:English
Published: MDPI AG 2021-04-01
Series:Materials
Subjects:
Online Access:https://www.mdpi.com/1996-1944/14/9/2158
Description
Summary:Sol–gel layers have been the subject of many studies in recent decades. However, very little information exists about layers in which carbon structures are developed in situ. Using the spin-coating method, we obtained thin iron-doped SiO<sub>2</sub>/C composite films. The results of Raman spectroscopy showed that our samples consisted of graphitic forms and polymers. The latter’s contribution decreases with rising temperature. FTIR and EDS studies show changes in carbon distribution on top of the layer, depending on the sintering temperature. The samples sintered at 800 °C showed a significant increase in the contribution of carbon forms to the layer’s surface. Therefore, high conductivity can be observed in this sample. The results of XPS spectroscopy showed that the contribution of sp<sup>3</sup> hybridized carbon increases after etching. The total electrical conductivity, studied by a DC four-wire technique, increased with the temperature and showed almost linear characteristics with significant changes below 150 K. The reduced activation energy plot has a positive temperature coefficient, which is a characteristic property of the conductive polymers in a metallic regime of conductivity.
ISSN:1996-1944