Energy Materials & Thermoelectrics

Journal of Materials Science

, Volume 48, Issue 7, pp 2836-2845

Open Access This content is freely available online to anyone, anywhere at any time.

Effects of impurities on the lattice dynamics of nanocrystalline silicon for thermoelectric application

  • Tania ClaudioAffiliated withJülich Centre for Neutron Science, JCNS and Peter Grünberg Institut PGI, JARA-FITFaculté des Sciences, Université de Liège Email author 
  • , Gabi SchierningAffiliated withFaculty of Engineering and Center for NanoIntegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen
  • , Ralf TheissmannAffiliated withFaculty of Engineering and Center for NanoIntegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen
  • , Hartmut WiggersAffiliated withFaculty of Engineering and Center for NanoIntegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen
  • , Helmut SchoberAffiliated withInstitut Laue Langevin
  • , Michael Marek KozaAffiliated withInstitut Laue Langevin
  • , Raphaël P. HermannAffiliated withJülich Centre for Neutron Science, JCNS and Peter Grünberg Institut PGI, JARA-FITFaculté des Sciences, Université de Liège

Abstract

Doped silicon nanoparticles were exposed to air and sintered to form nanocrystalline silicon. The composition, microstructure, and structural defects were investigated with TEM, XRD, and PDF and the lattice dynamics was evaluated with measurements of the heat capacity, of the elastic constants with resonant ultrasound spectroscopy and of the density of phonon states (DPS) with inelastic neutron scattering. The results were combined and reveal that the samples contain a large amount of silicon dioxide and exhibit properties that deviate from bulk silicon. Both in the reduced DPS and in the heat capacity a Boson peak at low energies, characteristic of amorphous SiO2, is observed. The thermal conductivity is strongly reduced due to nanostructuration and the incorporation of impurities.