Room temperature picowatt-resolution calorimetry

Abstract

Picowatt-resolution calorimetry is necessary for fundamental studies of nanoscale energy transport. Here, we report a microfabricated device capable of <4 pW resolution—an order of magnitude improvement over state-of-the-art room temperature calorimeters. This is achieved by the incorporation of two important features. First, the active area of the device is thermally isolated by thin and long beams with a total thermal conductance (G) of ∼600 nW/K. Further, a bimaterial cantilever thermometer capable of a temperature resolution (ΔTres) of ∼4 μK is integrated into the microdevice. The small thermal conductance and excellent temperature resolution enable measurements of heat currents (q = G × ΔTres) with a resolution <4 pW.