Thermal and thermoelectric properties of nitride metal/semiconductor superlattices

Since the 1960s, researchers exploring the potential of artificially-structured materials for applications in quantum electronic devices have sought combinations of metals and dielectrics that could be combined on the nanoscale with atomically-sharp interfaces. Early work with multilayers of polycrystalline elemental metals and amorphous dielectrics showed promise in tunneling devices. More recently, similar metal/dielectric multilayers have been utilized to demonstrate novel optical metamaterials. These metal/dielectric multilayers, however, are not amenable to atomic-scale control of interfaces. We developed the first epitaxial metal/semiconductor multilayers that are free of extended defects. These rocksalt nitride superlattices have atomically sharp interfaces and properties that are tunable by alloying, doping and quantum size effects. Furthermore, these nitride superlattices exhibit exceptional mechanical hardness, chemical stability and thermal stability up to ~1000°C. In this thesis, I have described the growth and transport properties of nitride metal/semiconductor superlattices including (Ti,W)N/(Al,Sc)N and (Hf, Zr)N/ScN). Potential applications in thermoelectric devices and plasmonic metamaterials are outlined. Futhermore, I have described recent experiments that employ these superlattices as model materials for investigating the fundamentals of heat transport in nanostructured materials