Micro- and Nanoscale Phonon Heat Transport in Silicon

Micro- and nanoscale energy transport in semiconductors is one of the critical research areas for emerging nano-electronics. Key features of phonon dispersion curves are re-examined, which motivates the use of phonon density of states obtained from ab initio calculations as a basis for constructing a semi-phenomenological thermal conductivity model. Thermal conductivity data on silicon nanowires are analyzed to identify dominant phonon modes. The consistency of the present thermal conductivity model is examined by comparing its prediction with the thermal conductivity data from bulk germanium samples with controlled amount of point defects. The thermal conductivity modeling study provides input parameters for a two-fluid phonon transport model for silicon and related semiconductors, which can play an important role in computer aided design of nanoelectronic devices and simulation of ultra-fast phenomena.