Thermal conductivity of nanowires

Thermal conductivity of nanowires (NWs) is a crucial criterion to assess the operating performance of NWs-based device applications, such as in the field of heat dissipation, thermal management, and thermoelectrics. Therefore, numerous research interests have been focused on controlling and manipulating thermal conductivity of one-dimensional materials in the past decade. In this review, we summarize the state-of-the-art research status on thermal conductivity of NWs from both experimental and theoretical studies. Various NWs are included, such as Si, Ge, Bi, Ti, Cu, Ag, Bi2Te3, ZnO, AgTe, and their hybrids. First, several important size effects on thermal conductivity of NWs are discussed, such as the length, diameter, orientation, and cross-section. Then, we introduce diverse nanostructuring pathways to control the phonons and thermal transport in NWs, such as alloy, superlattices, core-shell structure, porous structure, resonant structure, and kinked structure. Distinct thermal transport behaviors and the associated underlying physical mechanisms are presented. Finally, we outline the important potential applications of NWs in the fields of thermoelectrics and thermal management, and provide an outlook.