Fano-type Effect in Hydrogen-Terminated Pure Nanodiamond.

Kudryavtsev, Oleg S; Bagramov, Rustem H; Satanin, Arkady M; Shiryaev, Andrey A; Lebedev, Oleg I; Romshin, Alexey M; Pasternak, Dmitrii G; Nikolaev, Alexander V et al. · Nano Lett · 2022

basic_science · Level V

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Abstract

Two novel properties, unique for semiconductors, a negative electron affinity and a high p-type surface electrical conductivity, 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, for the first time to our knowledge, we observe a transparency peak at 1328 cm<sup>-1</sup> in the infrared absorption of hydrogen-terminated pure (undoped) nanodiamonds. This new optical property is ascribed to Fano-type destructive interference between zone-center optical phonons and free carriers (holes) appearing in the near-surface layer of hydrogenated nanodiamond. This work opens the way to explore the physics of electron-phonon coupling in undoped semiconductors and promises the application of H-terminated nanodiamonds as a new optical material with induced transparency in the infrared optical range.