Lecture by Dr. Chao Yuan


IEE SAS invite you to a lecture by Dr. Chao Yuan (Instit. Technol. Sci, Wuhan Univ., China).
November 10, 2023, 10,00 a.m., in IEE SAS meeting room 101.

Pump-probe thermoreflectance techniques for non-contact and non-invasively characterizing the thermal properties of wide bandgap semiconductors


Pump-probe thermoreflectances (pump-probe TR) have emerged as the powerful and versatile
tools for the characterization of wide bandgap (WBG) and ultrawide bandgap (UWBG) semiconductor
thermal transport properties. This lecture begins with the basic principles and standard implementations of
pump-probe TR techniques, illustrating that when analysing WBG and UWBG materials or devices with
pump-probe TR or TTI, a metal thin-film layer is often required. Due to the transparency of the
semiconductor layers to light sources with sub-bandgap energies, these measurements directly on
semiconductors with bandgaps larger than 3 eV remain challenging. This lecture then summarizes the
general applications of pump-probe TR and TTI techniques for characterizing WBG and UWBG materials
where thin metals are utilized, followed by introducing more advanced approaches to conventional pumpprobe TR methods, which achieve the direct characterizations of thermal properties on GaN-based materials
without the use of thin-film metals. Discussions of these techniques show that they provide more accurate
results and rapid feedback and would ideally be used as a monitoring tool during manufacturing. Finally, this
lecture concludes with a summary that discusses the current limitations and proposes some directions for
future development.