Two novel properties, unique for semiconductors: a negative electron affinity [1-2], and a high p-type surface electrical conductivity [3-4], were discovered in diamond at the end of the last century. Both properties appear when the diamond surface is hydrogenated. A natural question arises: is the influence of the surface hydrogen on diamond limited only to the electrical properties? Here, we report the first observation of a transparency peak at 1328 cm-1 in IR absorption of hydrogen-terminated pure (undoped) nanodiamonds. This new optical property is ascribed to Fano-type destructive interference between zone-center phonons and free carriers (holes) appearing in the near-surface layer of hydrogenated nanodiamond. Our work opens the way to exploring the physics of electron-phonon coupling in undoped diamonds and promises the application of the H-terminated nanodiamonds as a new optical material with an induced transparency in IR optical range.
@article{arxiv.2106.03230,
title = {Fano-type effect in hydrogen-terminated pure nanodiamond},
author = {O. S. Kudryavtsev and R. H. Bagramov and A. M. Satanin and A. A. Shiryaev and O. I. Lebedev and A. M. Romshin and D. G. Pasternak and A. V. Nikolaev and V. P. Filonenko and I. I. Vlasov},
journal= {arXiv preprint arXiv:2106.03230},
year = {2022}
}