Accession Number : ADA624950


Title :   A New Regime of Nanoscale Thermal Transport: Collective Diffusion Increases Dissipation Efficiency


Descriptive Note : Journal article


Corporate Author : COLORADO UNIV AT BOULDER


Personal Author(s) : Hoogeboom-Pot, Kathleen M ; Hernandez-Charpak, Jorge N ; Gu, Xiaokun ; Frazer, Travis D ; Anderson, Erik H ; Chao, Weilun ; Falcone, Roger W ; Yang, Ronggui ; Murnane, Margaret M ; Kapteyn, Henry C


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a624950.pdf


Report Date : 21 Apr 2015


Pagination or Media Count : 8


Abstract : Understanding thermal transport from nanoscale heat sources is important for a fundamental description of energy flow in materials as well as for many technological applications including thermal management in nanoelectronics and optoelectronics, thermoelectric devices, nanoenhanced photovoltaics, and nanoparticle-mediated thermal therapies. Thermal transport at the nanoscale is fundamentally different from that at the macroscale and is determined by the distribution of carrier mean free paths and energy dispersion in a material, the length scales of the heat sources, and the distance over which heat is transported. Past work has shown that Fourier's law for heat conduction dramatically overpredicts the rate of heat dissipation from heat sources with dimensions smaller than the mean free path of the dominant heat-carrying phonons. In this work we uncover a new regime of nanoscale thermal transport that dominates when the separation between nanoscale heat sources is small compared with the dominant phononmean free paths. Surprisingly the interaction of phonons originating from neighboring heat sources enables more efficient diffusive-like heat dissipation, even from nanoscale heat sources much smaller than the dominant phonon mean free paths. This finding suggests that thermal management in nanoscale systems including integrated circuits might not be as challenging as previously projected. Finally, we demonstrate a unique capability to extract differential conductivity as a function of phonon mean free path in materials, allowing the first (to our knowledge) experimental validation of predictions from the recently developed first-priniples calculations.


Descriptors :   *DISSIPATION , *MICROELECTRONICS , *THERMOELECTRICITY , *TRANSPORT PROPERTIES , COOLING , ELECTRON BEAM LITHOGRAPHY , ENERGY DENSITY , EXPERIMENTAL DESIGN , FABRICATION , FOURIER ANALYSIS , HARMONICS , HEAT TRANSFER , INTEGRATED CIRCUITS , MEAN FREE PATH , NANOWIRES , PHONONS , SILICON , SPECTROSCOPY , TEMPERATURE CONTROL , THERMAL CONDUCTIVITY , THERMAL RADIATION , X RAYS


Subject Categories : Electrooptical and Optoelectronic Devices
      Optics
      Solid State Physics
      Thermodynamics


Distribution Statement : APPROVED FOR PUBLIC RELEASE