Spectrally and spatially resolved electron and phonon heat transfer mechanisms across interfaces
Abstract
Approved for Public ReleaseSpectrally and spatially resolved electron and phonon heat transfer mechanisms across interfacesProfessor Patrick E. HopkinsOne of the primary bottlenecks that is inhibiting ideal operating efficiency and performance in RF and power devices is the inability to effectively mitigate temperature rises, especially wide bandgap and ultrawide bandgap-based devices of interest to the Navy. These deleterious temperature rises originate from the thermal boundary resistances (TBRs) across heterogeneous interfaces, and thus methods to reduce these TBRs are an important consideration in material and device development and design. Recent theories have suggested that local structures and defects around interfaces can decrease TBR through the increased scattering of so-called #interfacial modes#, which are vibrational modes that are quasi-localized to an interfacial region. Experimental evidenceof this effect is lacking, however, and thus accurate measurements of the role of these interfacial modes on TBR is of utmost importance to increase our fundamental understanding of heat transfer around interfaces and design more thermally efficient interfaces. However, the current state of the art (SOA) in experimental metrologies for determining TBR do not have the spatial or spectral resolution to resolve these specific electron and phonon interfacial scattering and conversion processes, thus leaving the fundamental mechanisms that drive the reductions in TBR unvalidated experimentally. The overarching objective of this work is thus to use recent advances in the SOA of the thermal metrologies to resolve the spectrally and spatially varying electron and phonon heat transfer mechanisms across interfaces, particularly focusing on interfaces that are established as limiting thermal resistances in power devicesand other technologies of interest to the DoD (e.g., GaN, AlN, AlGaN, and diamond). More specifically, this proposed program will use two recent experimental capabilities in PI-Hopkins# lab to study the spectral and spatial extent of electron and phonon thermal boundary resistance across solid interfaces with and without interfacial disorder. These experimental advances will enable unprecedented probing into how electron and phonon transport spatially and spectrally change close to interfaces, thus providing unprecedented advances in our understanding of the fundamental mechanisms that drive thermal transport and scattering across and near interfaces. The proposed experimental studies, broken down into the 4 proposed Tasks listed below, will experimentally validate the hypothesis that interfaces, defects and disorder can impact TBR, and how the contribution of interfacial phonon modes accelerate heat transfer (both electron and phonon driven) across interfaces. Task 1: Spatially resolved electron and phonon scattering near interfacesTask 2: Spectral contribution of interfacial modes to TBRTask 3: Spectral electron-phonon coupling across metal/non-metal interfacesTask 4: Spatial and spectral contribution of interfacial phonon modes at defected interfaces
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 24, 2023
- Source ID
- N000142312630
Entities
People
- Patrick Hopkins
Organizations
- Office of Naval Research
- United States Navy
- University of Virginia