However, the most prominent hurdle to study heat transport at nanoscales is manifested as the lack of instruments and measurement techniques to accurately quantify flux of heat at these length scales. This challenge arises from the fact that the small physical size and miniscule signals that need to be recorded from these systems require unprecedented precisions and resolutions. To address this need, I have studied fundamental principles governing high-resolution calorimetry experiments and took these understandings to developed two types of calorimeters [Sadat et al, App. Phys. Lett., 2011 and Sadat et al, App. Phys. Lett., 2013], suitable for study of energy transport at nanoscales. Both devices feature low thermal conductance in conjunction with the high resolution Bimaterial Cantilever (BMC) and Resistance thermometers that correspondingly enabled me to perform calorimetry measurements with picowatts resolutions. While the BMC version successfully demonstrated the feasibility of such high-resolution calorimetry measurements, I developed second device envisioning a device tailored to the specific goal of studying heat transport in the limiting one dimensional case of single molecule entities. For this purpose, after detailed analysis of the noise characteristics of resistive thermometers, I developed techniques to improve the resolution of generally renowned as low-resolution resistance thermometers by an order of magnitude [Sadat et al, Rev. Sci. Inst., 2012].
Research Directions
Research Portfolio
Experimental Study of Near-Field Radiative Heat Transfer
Ultra-High-Resolution Heat Flow Calorimetry for Micro/Nanoscale Studies
Nanoscale Thermometry Using Point Contact Thermocouples
Concurrent Study of Charge Transport and Thermopower in Metal-Molecule-Metal Junctions
Large Deflection Spiral-Shaped Micro-Mirror Actuator for Free Space Optical Switching
The interacting plates of the capacitor are comprised of two electrodes, one called fixed and the other moving electrode. The fixed electrode is realized using a metallic path, patterned on the substrate and the moving electrode is a spiral-shaped thin film silicon oxide beam. The two plates are fabricated on two different chips which subsequently, were aligned and placed in proper orientation using a micro-manipulator system and fixed using adhesive.
The design utilizes the enhanced flexibility of the spiral-shaped electrode while keeping a small overall footprint of 600 μm × 600 μm for the assembled device. I modeled the device using a coupled electromechanical model and experimentally characterized its performance using a reflection measurement approach. A continuous rotational actuation of 17◦ has been achieved with an actuation voltage of 235 V.