Nanomechanical thermometry for probing sub-nW thermal transport

Sangmin Oh; Nehpal Singh Shekhawat; Osama Jameel; Amit Lal; Chung Hoon Lee

doi:10.1038/s41378-024-00770-w

Nanomechanical thermometry for probing sub-nW thermal transport

Microsyst Nanoeng. 2024 Oct 18;10(1):148. doi: 10.1038/s41378-024-00770-w.

Authors

Sangmin Oh¹, Nehpal Singh Shekhawat¹, Osama Jameel², Amit Lal³, Chung Hoon Lee⁴

Affiliations

¹ Electrical and Computer Engineering Department, Marquette University, Milwaukee, WI, USA.
² Polytec Inc., 16400 Bake Pkwy, Irvine, CA, USA.
³ Electrical and Computer Engineering Department, Cornell University, Ithaca, NY, USA.
⁴ Electrical and Computer Engineering Department, Marquette University, Milwaukee, WI, USA. [email protected].

Abstract

Accurate local temperature measurement at micro and nanoscales requires thermometry with high resolution because of ultra-low thermal transport. Among the various methods for measuring temperature, optical techniques have shown the most precise temperature detection, with resolutions reaching (~10^-9 K). In this work, we present a nanomechanical device with nano-Kelvin resolution (~10^-9 K) at room temperature and 1 atm. The device uses a 20 nm thick silicon nitride (SiN) membrane, forming an air chamber as the sensing area. The presented device has a temperature sensing area >1 mm² for micro/nanoscale objects with reduced target placement constraints as the target can be placed anywhere on the >1 mm² sensing area. The temperature resolution of the SiN membrane device is determined by deflection at the center of the membrane. The temperature resolution is inversely proportional to the membrane's stiffness, as detailed through analysis and measurements of stiffness and noise equivalent temperature (NET) in the pre-stressed SiN membrane. The achievable heat flow resolution of the membrane device is 100 pW, making it suitable for examining thermal transport on micro and nanoscales.