Characterisation of defects in amorphous carbon by electron paramagnetic resonance

A review is given of what has been learnt about defects in hydrogenated and non-hydrogenated amorphous carbon using the technique of electron paramagnetic resonance (EPR). Firstly, there is a brief description of how the population of defects can be obtained and of the uncertainties and possible errors which may arise. A summary is then presented of the main results obtained so far by EPR - in particular the variation of the spin density and EPR linewidth with changes in structure and composition of a-C and a-C:H. An interpretation of the data is given and suggestions are made about the nature of the defects. (C) 2001 Elsevier Science B.V. All rights reserved.