Scientists at Tokyo Institute of Technology (Tokyo Tech) and their collaborators have developed a micrometer-wide thermometer that is sensitive to heat generated by optical and electron beams, and can measure small and rapid temperature changes in real time. This new device can be used to explore heat transport on the micro- and nano-scales, and in optical microscopy and synchrotron radiation experiments.
There is an urgent need for a device that can measure thermal behavior on the nanoscale and in real time, as this technology could be applied in photo-thermal cancer treatment as well as in advanced research on crystals, optical light harvesting, etc.
(a) Video still showing a tightly focused laser beam making contact with the thermocouple. (b) Graph showing the thermocouple's response over time to different laser powers (3.6 and 1.8 mW) at different repetition rates, on glass and on the silicon nitride membrane (ΔT: change in temperature, τ: time for temperature rise and decay).
Credit: Scientific Reports
Moreover, a miniaturized thermal microscopy system with a nanoscale heat source and detector is essential for future development of next-generation transistors that will be employed in designing new nanoscale devices.
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 micro-thermocouple recently developed by scientists at Tokyo Institute of Technology and their collaborators is of major importance to researchers in many fields.
This device consists of a gold and nickel thermocouple on a silicon nitride membrane and is miniaturized to the extent that the electrodes are only 2.5 μm wide and the membrane is just 30 nm thick. For such a system to be used as a thermal characterization device, i.e., a thermometer, it must show sensitivity to temperature change.
The developed micro-thermocouple exhibited high responsiveness to heat generated by a laser and an electron beam. Importantly, tiny temperature changes were measured by the developed thermocouple for both types of heating.
An already developed miniaturization process was used to prepare the micro-thermocouple, but critical improvements were made. In the established method, a cross pattern of metal stripes with widths of a few micrometers is created, so that a thermocouple is produced. The researchers at Tokyo Institute of Technology and their colleagues used this technique to create a pattern on a nano-thin silicon nitride membrane, which enhanced the device sensitivity and enabled it to respond faster.
Through this approach, a thermometer that could measure fast and small temperature changes was successfully produced, with the measurements being performed through the nano-thin silicon nitride membrane.
As explained above, both a nanoscale heat source and a nanoscale detector are needed for a miniaturized thermal microscopy system. These requirements were successfully satisfied by the researchers, who 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.
So, combined with the micro-thermocouple detector, a nanoscale thermal microscopy system was achieved. This system can be regarded as a new "toolbox" for investigating heat transport behavior on the micro- and nano-scales, with many important applications in a wide range of fields.
Emiko Kawaguchi | EurekAlert!
Machine learning methods provide new insights into organic-inorganic interfaces
04.08.2020 | Technische Universität Graz
Unusual electron sharing found in cool crystal
31.07.2020 | Nagoya University
An international research team has found a new approach that may be able to reduce bone loss in osteoporosis and maintain bone health.
Osteoporosis is the most common age-related bone disease which affects hundreds of millions of individuals worldwide. It is estimated that one in three women...
Traditional single-cell sequencing methods help to reveal insights about cellular differences and functions - but they do this with static snapshots only...
“Core-shell” clusters pave the way for new efficient nanomaterials that make catalysts, magnetic and laser sensors or measuring devices for detecting electromagnetic radiation more efficient.
Whether in innovative high-tech materials, more powerful computer chips, pharmaceuticals or in the field of renewable energies, nanoparticles – smallest...
An international research team with Prof. Cornelia Denz from the Institute of Applied Physics at the University of Münster develop for the first time light fields using caustics that do not change during propagation. With the new method, the physicists cleverly exploit light structures that can be seen in rainbows or when light is transmitted through drinking glasses.
Modern applications as high resolution microsopy or micro- or nanoscale material processing require customized laser beams that do not change during...
Although no life has been detected on the Martian surface, a new study from astrophysicist and research scientist at the Center for Space Science at NYU Abu...
23.07.2020 | Event News
21.07.2020 | Event News
07.07.2020 | Event News
05.08.2020 | Physics and Astronomy
05.08.2020 | Health and Medicine
05.08.2020 | Earth Sciences