Phonons in Silicon Nanowires

Cubic silicon in bulk form has changed the modern landscape of electronics and electrooptics. The physical and chemical properties of Si are perhaps the best understood of any crystalline solid. It is therefore a crucial crystalline material to research and understand the possibilities for new devices at the nanoscale where quantum confinement phenomena drive the formation of new electronic and phonon states. This chapter focuses on phonon properties expected for “confined” Si in the form of nanowires. It reviews the calculations of the phonon dispersion in small diameter nanowires as well as experiments that seek to probe the change in the phonon dispersion and the associated physical properties. Discussion is presented on the observation and interpretation of data on inelastic light scattering from nanowire phonons (Raman and Brillouin Spectroscopy), thermal conductivity and specific heat.