The chemical bonding state of nitrogen in kapton-derived carbon film and its effect on the graphitization process

The chemical bonding state of the nitrogen which remains in the carbon films derived from a polyimide Kapton film was studied by X-ray photoelectron spectroscope and related to the changes in structure and transport properties. The nitrogen remaining after heal treatment up to 2200 degrees C was in a tertiary bonding state, replacing carbon atoms in hexagonal layers, which was supported by theoretical calculation based on ab-initio molecular orbital theory. The departure of substituted nitrogen atoms from hexagonal layers showed a good correspondence with structure development and changes in transport properties, the presence of nitrogen depressing the developments in structure and transport properties. After the departure of nitrogen above 2300 degrees C graphitization of the films was very remarkable. (C) 1998 Elsevier Science Ltd. All rights reserved.