Title: Design and Optimization of a Composite Heat Spreader to Improve the Thermal Management of Three-Dimensional Integrated Circuits

Wednesday, September 14, 2022, 10AM Pacific Bourns Hall A341

Abstract: Tungsten Diselenide (WSe2), one valuable member of transition metal dichalcogenides, has attracted intensive attentions and emerged as promising candidates for advanced applications as field-effect transistors and light-emitting diodes. Understanding the microscopic lattice dynamics is essential for regulating the thermal properties of WSe2 to enhance the functionality and stability of WSe2-based devices. Here, by combining inelastic X-ray scattering and first-principles calculations, the lattice dynamics of WSe2 was investigated comprehensively. We performed the first measurements of the temperature-dependent phonon dispersions and the mode Grüneisen parameters of bulk WSe2, which are found to be in better agreement with the calculations on the monolayer system than those of the bulk. This observation indicates that lattice dynamics in bulk WSe2 hold the characterization of monolayers. We also performed the high-pressure IXS measurements on acoustic phonon in bulk WSe2 and observed the significant pressure-induced phonon stiffening. The pressure-dependent lattice dynamics are very useful to study the strain effects on the van der Waals interactions and anisotropic thermal conductivity in layered materials