Fano-type effect in hydrogen-terminated pure nanodiamond

TL;DR

This paper reports the discovery of a Fano-type destructive interference effect in hydrogen-terminated nanodiamonds, revealing new optical properties and opening avenues for studying electron-phonon interactions in undoped diamonds.

Contribution

It presents the first observation of a transparency peak in IR absorption of hydrogen-terminated nanodiamonds due to Fano interference, expanding understanding of surface effects in nanodiamond optics.

Findings

Observation of a transparency peak at 1328 cm-1 in IR absorption.

Attribution of the peak to Fano-type interference between phonons and free carriers.

Implication for potential optical applications of hydrogen-terminated nanodiamonds.

Abstract

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.