|About this Abstract
||MS&T21: Materials Science & Technology
||Phonon Properties of Materials: Modeling and Experimentation
||Tailoring Thermal Transport in Insulators Using Energetic Ions
||Vinay Chauhan, Joshua Ferrigno, Saqeeb Adnan, Zhandos Utegulov, Cody Dennett, Amey Khanolkar, Zilong Hua, Lingfeng He, David Hurley, Marat Khafizov
|On-Site Speaker (Planned)
Ion implantation and nuclear transmutation are established methods for tailoring electronic properties of semiconductors. In this presentation, we discuss use of ion beam modification to change phonon mediated thermal transport characteristics of insulating materials. Modulated thermorefleactance methods are used to measure conductivity of the modified regions, whereas transmission electron microscopy is employed to characterize microstructure. Implantation of xenon swift heavy ions accelerated to several tens of MeV into sapphire introduced an aligned array of ion tracks. These aligned nano-channels induce thermal anisotropy within the ion impacted region, which is attributed to directional scattering of phonons with ion tracks and phonon confinement effects. Irradiations of fluorite oxides such cerium and thorium dioxide with few MeV protons at elevated temperatures resulted in formation of dislocation loops. Careful analysis of thermal conductivity reduction under these implantation conditions suggests a very strong phonon scattering by the faulted loops owing to their long-range strain field.