Nanomechanical thermometry for probing sub-nW thermal transport

Abstract Measuring local temperature at the micro/nanoscale requires high resolution thermometery due to the ultra low thermal transport. Among practical temperature measurement methods, the optical method has demonstrated the highest temperature resolution (∼10−5 K). We present a sub micro-Kelvin resolution thermometry (∼10−8 K with a controlled environment, ∼10−6 K with a noisy open lab environment) that uses a 20 nm thick silicon nitride (SiN) membrane. The temperature resolution of the SiN membrane device is inversely proportional to the stiffness of the membrane. Analysis and measurements of the stiffness and noise equivalent temperature (NET) of the pre-stressed SiN membrane are presented. The achievable heat output resolution of the membrane device is sub nano-Watt (< 0.5 nW) and suitable for studying thermal transport at the micro/nanoscale.