Morphology, Acoustic Phonon Confinement, Phonon-Induced Strain and Dielectric Permittivity of Nominally Undoped Nano- and Micro-Crystalline Diamond

摘要

Physical nature of experimentally detected decrease in dielectric permittivity of nano- and micro-crystalline diamond films and powders observed at the grain size diminishment is discussed within frameworks of several well-known approaches. Most of them presume considerable contribution of sp~2-coordinated (graphite-like) fraction to dielectric properties of the granular material, which contradicts with available set of corresponding experimental data. An alternative explanation, based on Pekar model and assumptions on dominant contributions of phonon-induced strain and polarization effects of sp~3-coordinated intra-granular carbon atoms, is proposed. Obtained simulation results are compared with experimentally measured counterparts.