SUMMARY
The proposed research aims at thermally characterizing heated microcantilevers with or without the thermal interaction with the substrate, and investigating involved heat transfer mechanisms. This thesis also seeks to elucidate near-field radiative energy transport in multilayered structures. The results in this research will provide micro/nanoengineering and science community with better understanding of thermal energy transport in small length scales. This thesis includes three relevant parts. The first part seeks to understand electrical and thermal behaviors of heated microcantilevers far off the substrate. Particularly, the cantilevers are characterized in frequency domain under the periodic-heating operation. The cantilevers are also characterized at low temperatures and in vacuum, showing the feasibility of the heated cantilever in cryogenic environments. The second part focuses on measuring heat transfer rate from the cantilever to the substrate when the cantilever is engaged to the substrate. In order to measure the substrate surface temperature with a submicron spatial resolution, four-probe platinum resistive thermometers having a sub-100 nm sensing probe are fabricated. Combined micro and nanoscale heat transfer from the cantilever to the substrate is modeled and compared with the measurements, elucidating involved heat transfer mechanisms and associated thermal conductances. The third part deals with the radiative energy transport in multilayered structures. The effects of the surface and bulk polaritons on the radiative properties in a three-layered structure will be described. To predict the thermal energy transport in a planer multilayer structure, the fluctuation-dissipation theorem is employed together with a multilayer dyadic Green’s function. The near-field radiation between two multilayer structures separated by a small vacuum gap is predicted for different cases, and applied to improve the efficiency of microthermophotovoltaic systems.