The effect of hydrogen dilution on the structure of a-C : H

Walters, J.K. and Newport, R.J. and Parker, S.F. and Howells, W.S. and Bushnell-Wye, G. (1998) The effect of hydrogen dilution on the structure of a-C : H. Journal of Physics-Condensed Matter, 10 (19). pp. 4161-4176. ISSN 0953-8984. (Full text available)

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http://dx.doi.org/10.1088/0953-8984/10/19/004

Abstract

Two a-C:H samples were prepared using a fast-atom deposition system from acetylene and an acetylene/hydrogen gas mixture. Their structure was investigated using neutron and x-ny diffraction and infrared spectroscopy measurements. Compositional analysis shows that a 1:1 C2H2:H-2 mixture results in a change from a-C-77:H-23 to a-C-79:H-21, i.e. has a very small effect on the composition. The diffraction data also show that the addition of hydrogen to the precursor gas has no significant effect on the average bond distances and angles but shows a small change in the H-C-H and C-C-H correlations between the two samples. However, the infrared data show that there are significant changes in the bonding of hydrogen within the sample-changes which do not affect the average network structure. We observe a decrease in the amount of sp(3) CH2 and CH3 groups, and an increase in the fraction of sp(2) and sp(3) CH groups, with the formation of a second sp(2) CH bonding environment in the hydrogen-diluted sample. Therefore, in addition to providing useful structural information on these a-C:H samples, this set of experiments illustrates very well the complementary nature of the data from diffraction and spectroscopic techniques.

Item Type: Article
Subjects: Q Science
Q Science > QC Physics
Divisions: Faculties > Science Technology and Medical Studies > School of Physical Sciences > Functional Materials Group
Faculties > Science Technology and Medical Studies > School of Physical Sciences
Depositing User: J.M. Smith
Date Deposited: 29 Apr 2009 13:06
Last Modified: 02 Dec 2011 11:50
Resource URI: http://kar.kent.ac.uk/id/eprint/15998 (The current URI for this page, for reference purposes)
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