Tiny Thermometer Measures Minute Fluctuations

A research team in Japan has developed a thermometer that can measure rapid changes in temperature at the nanoscale.

AsianScientist (May 31, 2018) – Scientists at the Tokyo Institute of Technology (Tokyo Tech), Japan, have developed a micrometer-wide thermometer that can measure extremely small and rapid temperature changes in real time. Their findings are published in Scientific Reports.

A device that can measure thermal behavior on the nanoscale—and in real time—has wide applications in clinical and basic research. Moreover, a miniaturized thermal microscopy system with a nanoscale heat source and detector is essential for future development of next-generation transistors.

In the present study, a research group led by Professor Junko Morikawa at Tokyo Tech has developed a micro-thermocouple that can be used to explore heat transport on the micro- and nano-scales, as well as in optical microscopy and synchrotron radiation experiments.

A thermocouple is an electrical device consisting of two dissimilar electrical conductors forming electrical junctions at differing temperatures. A thermocouple produces a temperature-dependent voltage, which can be interpreted to measure temperature.

The device developed by Morikawa’s team consists of a gold and nickel thermocouple on a silicon nitride membrane. The electrodes are only 2.5 μm wide, and the membrane is just 30 nm thick. The researchers created a pattern on the nano-thin silicon nitride membrane, enhancing the device’s sensitivity and enabling it to respond to changes in temperature faster.

The researchers then demonstrated the sensitivity of their device by projecting a laser and an electron beam on it. The micro-thermocouple exhibited high responsiveness to both heat sources.

To develop a miniaturized thermal microscopy system, both a nanoscale heat source and a nanoscale detector are required. The researchers thus used the nano-thin membrane and a tightly focused laser or electron beam to create a heat source with a diameter of less than 1 μm.

According to the researchers, the resulting nanoscale thermal microscopy system can be regarded as a new tool for investigating heat transport behavior on the micro- and nano-scales, with many important applications in a wide range of fields.

The article can be found at: Balčytis et al. (2018) Micro-Thermocouple on Nano-membrane: Thermometer for Nanoscale Measurements.


Source: Tokyo Institute of Technology; Photo: Pixabay.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Asian Scientist Magazine is an award-winning science and technology magazine that highlights R&D news stories from Asia to a global audience. The magazine is published by Singapore-headquartered Wildtype Media Group.

Related Stories from Asian Scientist