  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.
