IBM pioneers nanoscale thermometry

March 09, 2016 // By Paul Buckley
Scientists from IBM and ETH Zurich have invented a technique to measure the temperature of nanoscale objects - a key challenge in nanoscience - which could pave the toward being able to precisely characterize the temperature of new transistor designs to meet the demand of future cognitive computers.

The patent-pending invention has been described in the peer-review journal Nature Communications in a paper titled 'Temperature mapping of operating nanoscale devices by scanning probe thermometry.' The nanoscale measurement technique comes from the IBM lab which was previously responsible for inventing the scanning tunneling microscope and the atomic force microscope.

Accurately measuring the temperature of objects at the nanoscale has been challenging scientists for decades. Current techniques are not accurate and they typically generate artifacts, limiting their reliability.

In the 1980s, IBM scientists Gerd Binnig and the late Heinrich Rohrer wanted to directly explore a surface's electronic structure and imperfections. The instrument they needed to take such measurements didn't exist, yet. So they did what any good scientist would do: they invented one. It became known as the scanning tunneling microscope (STM), opening the door to nanotechnology. More than 30 years later IBM scientists continue to follow in the footsteps of Binnig and Rohrer and with their latest invention.

"We started back in 2010 and simply never gave up. Previous research was focused on a nanoscale thermometer, but we should have been inventing a thermometer for the nanoscale—an important distinction. This adjustment led us to develop a technique which combines local thermal sensing with the measuring capability of a microscope—we call it scanning probe thermometry," says Dr. Fabian Menges, an IBM postdoc and co-inventor of the technique.

The most common technique to measure temperature on the macroscale is to bring a thermometer into thermal contact with the sample. This is how a fever thermometer works. Once it's placed under our tongue it equilibrates to our body temperature so that we can determine our temperature at a healthy 37ºC.

Unfortunately, it gets a little more challenging when using a thermometer to measure a nanoscopic object.  For example, it would be impossible to use a typical thermometer to measure the temperature of an individual virus. The size of the virus is too small and the thermometer cannot equilibrate without disturbing the virus temperature.

To solve the challenge, IBM scientists developed a single scan non-equilibrium contact thermometry technique to measure the temperature of nanoscopic objects using a scanning probe. As the scanning probe thermometer and the object cannot thermally equilibrate at the nanoscale, two signals are measured simultaneously: a small heat flux, and its resistance to heat flow. Combining the two signal the temperature of nanoscopic objects can then be quantified for an accurate result.