Thermal Conductivity of Suspended Si Nanostructures: Design and Fabrication
Keywords:Si Nanostructures, Thermal Conductivity, Nanoscale Heat Transfer.
It is presented a process for engineering suspended Si nanostructures in order to measure the thermalconductivity in Si thin films and nanowires based on standard photolithographic techniques. Unlike previous works wherethe nanostructure was typically grown ex situ, and then mechanically placed and contacted between the two microheaterswhich introduce a contact thermal resistance that difficult an easy interpretation of the experimental results byincreasing the uncertainty of the measured thermal conductance of the nanostructure; in this research, the nanostructureis defined from silicon-on-insulator wafers via FIB with the objective to minimize the thermal contact resistance betweenthe nanostructure under test and the heat sources. It has been demonstrated by experimental measurements that thissuspended device is well adapted for the measurement, control and analysis of the thermal conductivity of nanoscale Sithin films and nanowires. FIB micro-fabrication strategy could be used to obtain Si based nanostructures with very lowthermal conductivity which is a desirable characteristic in thermoelectric applications for thermal energy harvesting andsolid state refrigeration as well.
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