Nanojoule thermal transfer in micromechanical heterostructures

We describe recent experiments on heat-transfer processes in silicon-nitride micromechanical heterostructures using nanoscale-science techniques. The influence of various media surrounding the structures, such as ethanol, air, and vacuum, on heat loss is discussed. Key factors investigated are thermal response time and thermomechanical sensitivity. Both the effects of ohmic and laser-irradiated heating are discussed. Using a heterostructured micromechanical calorimeter, heat-transfer processes at phase transitions are determined down to the nanojoule level.