Phonon Heat Conduction in Superlattices

摘要: Modern growth techniques such as molecular beam epitaxy (MBE) and metal- organic chemical vapor deposition (MOCVD) have enabled fabricating semiconductor superlattices (SLs) with monoatomic layer (ML) precision. Phonon propagation scattering in SLs are of both fundamental practical interest.1-4Phonon heat conduction has attracted considerable attentions due to the applications thermoelectric devices5-10and optoelectronic devices quantum well lasers detectors.11,12To realize efficient devices, low thermal conductivity materials sought because performance is determined by figure-of-merit Z=S2σ/k, where k conductivity, σelectrical S Seebeck coefficient.13Superlattices generally found values thus become candidates search for high materials.5,7,14Their unique electronic properties, particularly capability tailoring their properties through size effects, also make them essential building blocks many that must concurrently deal management issues caused poor conductivity. The freedom structures leads approaches band gap carrier pocket engineering improve power factor (S2σ) devices.5,6,14,15