Thermal conductivity of periodic array of intermolecular junctions of silicon nanowires

Recent studies on intramolecular junctions of silicon nanowires and carbon nanotubes have revealed a wealth of intriguing phenomena. However, the thermal properties of the intramolecular junctions of silicon nanowires (SiNWs) are not yet well understood. In this study periodic arrays of intramolecular junctions with different lattice orientations are investigated, and their thermal conductivities are calculated using nonequilibrium molecular dynamics (NEMD) simulations. Different from the X-shaped and Y-shaped junctions of carbon nanotubes, no distinct jump is found in the temperature profile at the junctions. Compared with straight pristine SiNWs of the same length, the thermal conductivity of the periodic array of intramolecular junctions is reduced. The underlying mechanism of the observed behavior is analyzed by the phonon spectral density of the atomic velocities. The dependence of temperature on the thermal conductivity of this junction array structure is discussed.

Result of this study shows that the thermal conductivity of periodic arrays of intramolecular junctions of SiNWs is clearly less than that of pristine nanowires .Figure optionsDownload as PowerPoint slideHighlights
► Thermal conductivity is reduced by this junction structure.
► Thermal conductivity is sensitive to segments growth direction.
► Underlying mechanism of observed behavior analyzed.