Preparation of pseudomorphicSi1−yCy/Si(001)heterostructures using Si molecular beam epitaxy with C obtained from SiC sublimation in a high-temperature cell has been studied. Thick(≈2000 Å)homogenousSi1−yCylayers,y⩽1.5&percent;,andSi1−yCy/Simultiple quantum well (MQW) structures,y⩽8&percent;,have been prepared. There is a growth temperature dependent surface roughness accumulating during the growth sequence that can lead to reduction of C induced strain. Temperature modulation during growth has been used to suppress this effect. Near band gap photoluminescence is reported fromSi1−yCy/SiMQW structures. ©1997 American Institute of Physics.