Tailoring Thermal Conductivity of Ge/Si Core-Shell Nanowires

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

Proceedings of the 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
  • Volume:
  • 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
  • Dokuz Eylül 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. ( 3) there is no significant variation in the thermal conductivity of Si NW for temperature values larger than 300. ( 4) the predicted thermal conductivity around 10 W m(-1)K(-1) is still larger than the value convenient for thermoelectric applications.