Ion irradiation induced crystalline disorder accelerates interfacial phonon conversion and reduces thermal boundary resistance
Thomas W. Pfeifer, Henry T. Aller, Eric R. Hoglund, Ethan A. Scott, John A. Tomko, Habib Ahmad, Alan Doolittle, Ashutosh Giri, Khalid Hattar, Alan J. H. McGaughey, Patrick E. Hopkins
Abstract
Traditional understanding of the thermal boundary resistance (TBR) across solid-solid interfaces posits that the vibrational densities of states overlap between materials dictates interfacial energy transport, with phonon scattering occurring at the interface. Using atomistic simulations, we show a mechanism for control of TBR; point defects near an interface can lead to both short- and midrange disorder, accelerating the conversion of vibrational energy between bulk and interfacial modes, ultimately reducing the TBR. We experimentally demonstrate this reduction through ion irradiation of gallium nitride and subsequently measuring the TBR across Al/GaN interfaces.