Scattering of acoustic phonons by embedded layers, extended defects and interfaces in diamond, silicon and II-VI compounds

The propagation of acoustic phonons in IV and II-VI group materials with various types of interfaces embedded inside the samples was investigated. A reverberation-type phenomenon is observed in diamond samples with implanted layers. Measurements of phonon scattering in ZnTe and CdTe with different impurity concentrations, dislocation density, and twinning systems have shown that in a pure large-grain ZnTe with chaotically placed twinning systems separated by 1–10 µm, the scattering by twins dominated. The phonon free path in such samples is reduced compared to the twin-free (though more doped) material by more than an order of magnitude. Si/SiGe double quantum wells demonstrated a perfect quality of interfaces when probed by phonons from the substrate side. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)