Direct Observation of Compositionally Homogeneous a-C: H Band-Gap-Modulated Superlattices

C. A. Davis, S. R. P. Silva, R. E. Dunin-Borkowski, G. A. J. Amaratunga, K. M. Knowles, and W. M. Stobbs
Phys. Rev. Lett. 75, 4258 – Published 4 December 1995
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Abstract

It is shown that amorphous hydrogenated carbon (a-C: H) band-gap-modulated superlattices can be observed by transmission electron microscopy. The layering proves to be well defined and it is demonstrated that changes in the band gap from 1.5 to 2.8 eV cannot be associated with ordered graphitic regions, in that crystalline regions larger than 0.5 nm are not observed. Differences in the amount of π bonding are found to lead to changes in the average atomic scattering factor. It is suggested that the changes in π bonding are associated with changes in local ordering that control the band gap.

  • Received 7 February 1995

DOI:https://doi.org/10.1103/PhysRevLett.75.4258

©1995 American Physical Society

Authors & Affiliations

C. A. Davis1, S. R. P. Silva2, R. E. Dunin-Borkowski1, G. A. J. Amaratunga2, K. M. Knowles1, and W. M. Stobbs1

  • 1Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3QZ, United Kingdom
  • 2Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, United Kingdom

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Vol. 75, Iss. 23 — 4 December 1995

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