Multi-quantum well structures with 3C-SiC wells between alpha -SiC barriers were grown in a two-step procedure by solid-source molecular beam epitaxy. First, one-dimensional wire-like 3C-SiC was nucleated selectively on terraces of the well-prepared off axis alpha -SiC(0 0 0 1) substrates at low temperature (T < 1500 K). Next, 3C-SiC lamellae were incorporated into the hexagonal layer material via simultaneous step-flow growth mode of both the 3C-SiC nuclei and the hexagonal substrate material at higher T and Si-rich conditions. In comparison to homopolytypic SiC layers, photoluminescence investigations revealed additional signals, which can be explained by optical transitions within the thin cubic well layers.