by josh perry, editor
researchers from the university of illinois – chicago (uic) have developed a new technique for precisely measuring the temperature and behavior of novel 2-d materials that could be used to design smaller and faster microprocessors, according to a report on the uic website.
robert klie, professor of physics. (jenny fontaine/uic)
uic scientists used scanning transmission electron microscopy and spectroscopy to measure the temperature of 2-d materials, known as transition metal dichalcogenides (tmd), at the atomic level and measure the expansion of 2-d materials when heated.
this study will help engineers understand how hot that microprocessors can get before breaking down as well as how much they will expand, which is critical in an industry that continues to reach for higher-powered devices and higher component density in tighter packages.
“traditional ways to measure temperature don’t work on tiny flakes of two-dimensional materials that would be used in microprocessors because they are just too small,” the article explained. “optical temperature measurements, which use a reflected laser light to measure temperature, can’t be used on tmd chips because they don’t have enough surface area to accommodate the laser beam.”
scanning transition electron microscopy sends a beam of electrons through an item to form an image. this allowed researchers to zoom in on and measure the vibration of atoms and electrons and use that kinetic energy as a measure of temperature.
“using a technique called electron energy-loss spectroscopy,” the article continued, “they were able to measure the scattering of electrons off the two-dimensional materials caused by the electron beam. the scattering patterns were entered into a computer model that translated them into measurements of the vibrations of the atoms in the material – in other words, the temperature of the material at the atomic level.”
with this data, the goal is to build electronics that will be less likely to overheat and use less power.
the research was recently published in physical review letters. the abstract read:
“two-dimensional materials, including graphene, transition metal dichalcogenides and their heterostructures, exhibit great potential for a variety of applications, such as transistors, spintronics, and photovoltaics.
“while the miniaturization offers remarkable improvements in electrical performance, heat dissipation and thermal mismatch can be a problem in designing electronic devices based on two-dimensional materials. quantifying the thermal expansion coefficient of 2d materials requires temperature measurements at nanometer scale.
“here, we introduce a novel nanometer-scale thermometry approach to measure temperature and quantify the thermal expansion coefficients in 2d materials based on scanning transmission electron microscopy combined with electron energy-loss spectroscopy to determine the energy shift of the plasmon resonance peak of 2d materials as a function of sample temperature.
“by combining these measurements with first-principles modeling, the thermal expansion coefficients (tecs) of single-layer and freestanding graphene and bulk, as well as monolayer mos2, mose2, ws2, or wse2, are directly determined and mapped.”