Quantitative probing of tip-induced local cooling with a resistive nanoheater/thermometer

• Published in: Applied physics letters Vol. 109; no. 25
• Main Authors: Hamian, Sina, Yun, Jeonghoon, Park, Inkyu, Park, Keunhan
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 19.12.2016
• Subjects: Applied physics; Atomic force microscopes; Atomic force microscopy; Conduction cooling; Conduction heating; Conductive heat transfer; Cooling; Detection; Electric contacts; Electron beam lithography; Nanowires; Photolithography; Substrates; Thermal conductivity; Thermal engineering
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4972792

This article reports the investigation of tip-induced local cooling when an atomic force microscope (AFM) cantilever tip scans over a joule-heated Pt nanowire. We fabricated four-point-probe Pt resistive nanothermometers having a sensing area of 250 nm × 350 nm by combining electron-beam lithography and photolithography. The electrical resistance of a fabricated nanothermometer is ∼27.8 Ω at room temperature and is linearly proportional to the temperature increase up to 350 K. The equivalent temperature coefficient of resistance is estimated to be ( 7.0 ± 0.1 ) × 10 − 4  K−1. We also joule-heated a nanothermometer to increase its sensing area temperature up to 338.5 ± 0.2 K, demonstrating that the same device can be used as a nanoheater. An AFM probe tip scanning over a heated nanoheater/thermometer's sensing area induces local cooling due to heat conduction through solid-solid contact, water meniscus, and surrounding air. The effective contact thermal conductance is 32.5 ± 0.8 nW/K. These results contribute to the better understanding of tip-substrate thermal interactions, which is the fundamental subject in tip-based thermal engineering applications.