IBM invents thermometer for the nanoscale
Image: Breakthrough technique measures temperature of nano- and macro- size objects.
IBM researchers have developed a scanning probe microscopy method to measure the temperature of a sample at the nanoscale.
Optical diffraction limits prevent today's high resolution thermometry methods from mapping variations in temperature with nanometre-scale spatial resolution.
Given this, Dr Fabian Menges from IBM and colleagues from IBM and ETH Zurich have pioneered a method to map temperature fields using a scanning thermal microscope.
Here, the microscope’s specialised probe is sensitive to local temperatures, in effect providing a nanoscale thermometer.
To map temperature fields at the nanoscale, the researchers equipped a custom-built high vacuum scanning thermal microscope with a highly phosphorous doped cantilever, to optimise the electrical conductivity of the tip.
The tip was used to simultaneously measure two signals - a small heat flux and the resistance of the material to heat flow - with measurements combined to yield more accurate results.
In this way, the researchers could include the effects of local variations of thermal resistance to measure the temperature of an indium arsenide nanowire, and a self-heated gold interconnect with a combination of a few-miliKelvin and few-nanometer spatial resolution.
IBM scientists, (Dr Fabian Menges right) with the scanning probe thermometer. [IBM Zurich]
"Our method eliminates tip-sample contact-related artifacts, a major hurdle that so far has limited the use of SPM for nanoscale thermometry," says Menges. "Not only is the scanning probe thermometer accurate, it's easy to operate, simple to build, and very versatile."
"It can be used to measure the temperature of nano- and micro-sized hot spots that can locally effect the physical properties of materials or govern chemical reactions in devices such as transistors, memory cells, thermoelectric energy converters or plasmonic structures," he adds. "The applications are endless.”
Research is published in Nature Communications.