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Title: Engineering the thermal conductivity along an individual silicon nanowire by selective helium ion irradiation

The ability to engineer the thermal conductivity of materials allows us to control the flow of heat and derive novel functionalities such as thermal rectification, thermal switching and thermal cloaking. While this could be achieved by making use of composites and metamaterials at bulk length-scales, engineering the thermal conductivity at micro- and nano-scale dimensions is considerably more challenging. Here, we show that the local thermal conductivity along a single Si nanowire can be tuned to a desired value (between crystalline and amorphous limits) with high spatial resolution through selective helium ion irradiation with a well-controlled dose. The underlying mechanism is understood through molecular dynamics simulations and quantitative phonon-defect scattering rate analysis, where the behaviour of thermal conductivity with dose is attributed to the accumulation and agglomeration of scattering centres at lower doses. Finally, we observed threshold dose beyond a crystalline-amorphous transition.
Authors:
 [1] ;  [2] ; ORCiD logo [3] ;  [4] ; ORCiD logo [5] ; ORCiD logo [5] ;  [5] ;  [5] ; ORCiD logo [5] ;  [2] ;  [2] ;  [6] ;  [2]
  1. National Univ. of Singapore (Republic of Singapore). Dept. of Electrical and Computer Engineering
  2. National Univ. of Singapore (Republic of Singapore). Dept. of Electrical and Computer Engineering, NUS Graduate School of Integrative Sciences and Engineering
  3. Tongji Univ., Shanghai (China). Center for Phononics and Thermal Energy Science
  4. Huaiyin Normal Univ., Jiangsu (China). School of Physics and Electronic adn Electrical Engineering
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences
  6. Univ. of Colorado, Boulder, CO (United States). Dept. of Mechanical Engineering
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 8; Journal Issue: 15919; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; nanowires; thermoelectrics
OSTI Identifier:
1376374