Abstract
It is shown that amorphous hydrogenated carbon (-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 bonding are found to lead to changes in the average atomic scattering factor. It is suggested that the changes in 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