We report an optical study of 3C-SiC layers grown on 6H-SiC substrates by VLS mechanism using a Si-Ge melt. The photoluminescence and μ-Raman results show a clear and significant incorporation of germanium in the layers from the melt. A photoluminescence emission attributed to Ge related transitions is observed in the infrared region. μ-Raman spectra exhibit two peaks related to the Ge-Ge and Si-Ge bonds. From the characteristics of these Raman peaks, it was found that the amount of Ge incorporated inside the 3C layers increases with increasing Ge content of the melt. This has been verified by Particle-Induced X-rays Emission (PIXE) measurements which gave a Ge concentration varying from ~ 1x1019 to ~ 1x1020 at.cm-3. All these results suggest that Ge incorporates in the VLS grown 3C layers by forming Si-Ge-(C) nanoclusters.