We synthesized semiconducting composite films of Si and Mo-silicide nanocrystals (NCs) by phase separation from amorphous Mo-Si alloy (Si:Mo = 12:1). Raman measurements show that the crystallization occurred at >= 700 degrees C. Transmission electron microscope images show that Si and Mo silicide NCs were grown to average diameters of 8 nm and 11 nm, respectively, by annealing at 800 degrees C. The electrical resistivity of the composite film is semiconducting (0.2-1.2 k Omega cm at room temperature depending on preparation conditions) and decreases with temperature increase. The thermal conductivity was reduced to 2.2 W m(-1) K-1 by enhancement of phonon scattering at NC interfaces, suggesting that the composite film is promising as a high-efficiency Si-based thermoelectric material. (C) 2013 Elsevier B. V. All rights reserved.