The objectives of the MuTT Lab are to (1) develop tools for studying microscale thermal transport phenomena (2) develop new materials which push the limits of achievable transport properties (thermal conductivity, interface conductance, heat capacity, thermoelectric power factor), and (3) to develop new device technologies based on these materials. Applications areas include the cooling of electronic devices, energy efficiency, thermoelectric energy conversion, and next-generation magnetic recording devices.
Time Domain Thermoreflectance
One of the key tools in our lab is our time-domain thermoreflectance system. The system utilizes femtosecond lasers to measure the thermal transport properties of thin films and interfaces with a spatial resolution in the range of 1 micron. The TDTR system can also generate and detect picosecond acoustic waves that can be used to determine geometric or elastic properties of subsurface layers. Recent advances by our lab also make it possible to measure the in-plane thermal conductivity of thin films using small spot sizes. By performing experiments at very high speed, it is not only possible to confine heat to a very thin layer near the surface, but one can also induce temperature gradients so steep that Fourier’s law is broken. Because these effects are related to the finite time/length-scales of heat carrier scattering, this allows us to directly probe the microscale processes responsible for transport properties.