Energy filtering enhancement of thermoelectric performance of   nanocrystalline Cr-Si composites
  We report on thermoelectric properties of nanocrystalline Cr$_{\rm 1-x}$Si$_{\rm x}$ composite films. As-deposited amorphous films were transformed into a nanocrystalline state with average grain size of 10--20~nm by annealing during in-situ thermopower and electrical resistivity measurements. The partially crystallized films, i.e. the films consisting of crystalline grains dispersed in the amorphous matrix, are a new type of the heterogeneous material where the nanocrystalline phase plays the role of scattering centers giving rise to a large contribution to the thermopower. We show that the thermopower enhancement is related to the energy dependent scattering (energy filtering) of the charge carriers on the nanograin interfaces. 
A.T. Burkov, S.V. Novikov, V.V. Khovaylo, J. Schumann
cond-mat.mtrl-sci