Phonon heat transport in silicon nanostructures

Phonon heat conduction is one of the critical research areas for nanoelectronics. The thermal conductivity of silicon nanostructures is studied to gain insight into heat conduction in silicon and related semiconductors. We experimentally show that phonon-boundary scattering results in a significant reduction in the thermal conductivity of crystalline silicon films of thickness below 100 nm at room temperature, which is consistent with the previously reported data for silicon nanowires. Analysis of the data suggests that phonon modes that dominate heat conduction in silicon are fully excited at temperatures substantially below the Debye temperature.