Chemical Sensing Properties of Carbon Nanofilms

V. Kumar, A.M. Zaitsev
The College of Staten Island and the Graduate Center of the City University of New York, US

Keywords: Carbon nanofilms, graphitization, sensors, plasma modification

Summary:

The chemical sensing properties of the carbon nanofilms obtained by high temperature graphitization of diamond, followed by plasma modification in different precursor gases is reported. The in situ study of graphitization along with the study of effect of plasma on sensitivity provided important information about the role of interatomic bonding and material order in carbon films. This was closely investigated by following thermally induced atomic ordering in carbon films deposited on quartz, and the resulting change in sensitivity to the vapors of NH3 and NO2, chosen for their opposite donor-acceptor properties. The two sensing parameters introduced to provide phenomenological description of the sensing are related to the material and surface properties of the films. A model for charge transport in carbon nanofilms based on thermally vibrating energy barriers which explains the mechanism for observed temperature and chemical sensitivity is also proposed.