We have synthesized, via molecular beam epitaxy alloys of SixSnyC1−x−ywith symmetric strain. In this work we report the growth of systems with varying compositions/band gaps including the first silicon‐based quaternary (Si/Ge/Sn/C) system, which offers an additional degree of freedom for strain and band gap engineering in Si‐based alloys. We report the growth of Si.955Sn.03C.015alloys up to 4500 A˚ in thickness and quaternaries of composition in the neighborhood of Si.835Ge.125Sn.03C.01. Infrared absorption spectroscopy and photoluminescence data have provided evidence of the potential for significant band gap modification in these alloys. ©1996 American Institute of Physics.