Tailoring thermal conductivity of Ge/Si core-shell nanowires

Sarikurt S., SEVİK C., Kinaci A., Haskins J. B., Cagin T.

TMS Middle East - Mediterranean Materials Congress on Energy and Infrastructure Systems, MEMA 2015, Doha, Qatar, 11 - 14 January 2015, pp.433-440 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Doi Number: 10.1002/9781119090427.ch46
  • City: Doha
  • Country: Qatar
  • Page Numbers: pp.433-440
  • Keywords: Ge/Si core-shell nanowires, thermal conductivity, thermoelectrics, NANOSCALE ELECTRONIC DEVICES, SILICON NANOWIRES, TRANSPORT-COEFFICIENTS, MOLECULAR-DYNAMICS, CARBON NANOTUBES, HETEROSTRUCTURES
  • Anadolu University Affiliated: Yes

Abstract

Low-dimensional nanostructured materials show large variation in their thermal transport properties. Here, we investigate the influence of core-shell architecture on nanowire (NW) thermal conductivity using molecular dynamics with Tersoff potentials Si-Ge, to design structures with desired thermal conductivity for thermoelectric device applications. To explore the parameter space, we have calculated thermal conductivity values of Ge/Si core-shell NWs having different lengths, cross-section sizes and Ge concentrations at several temperatures. We have found that (1) increasing the cross-sectional area of pure Si NW causes an increase in thermal conductivity (2) increasing the Ge core size in the Ge/Si structure results in a decrease in the thermal conductivity values at 300 K (3) there is no significant variation in the thermal conductivity of Si NW for temperature values larger than 300 K (4) the predicted thermal conductivity around 10 W m-1 K-1 is still larger than the value convenient for thermoelectric applications.