Sidebands in the Luminescence Spectra of Amorphous Hydrogenated Carbon

Abstract

Periodic oscillations in the luminescence spectra of amorphous hydrogenated carbon are reported. The period of these oscillations is 0.185 \ifmmode\pm\else\textpm\fi{} 0.010 eV, which is equal to the C-H wagging-mode energy. These oscillations are a function of the photoexcitation energy ${E}_{\mathrm{ex}}$; they appear when ${E}_{\mathrm{ex}}<~2.16$ eV and are absent when ${E}_{\mathrm{ex}}>~2.60$ eV, suggesting that localized electron-hole pairs are created by the former and extended states by the latter.