Hall measurements and photoluminescence of nitrogen doped free standing 3C-SiC films grown directly on undulant 6-inch Si substrates by a CVD method are reported. A clear difference in the electron mobility was observed before and after removal of the highly defected region near the Si/3C-SiC interface. Low-temperature photoluminescence spectra showed sharp features of the nitrogen bound exciton. Luminescence due to free exciton recombination, which is a good measure of the crystalline quality of samples, has been observed in as-grown 3C-SiC films formed directly on Si.