We present detailed studies of the structural properties of strain compensated Si/Si0.2Ge0.8 quantum cascade structures on relaxed Si0.5Ge0.5 buffer layers. To avoid surface roughening during the deposition of quantum well structures with high Ge concentrations it was necessary to reduce the growth temperature to 300degreesC. Cascade structures with up to 30 periods, each of them containing 28 layers, have been deposited with no noticeable degradation of the structural properties. Electroluminescence was observed from cascade structures based on the bound to continuum transition. The onset voltage of the electroluminescence scales with the number of cascade, indicating efficient vertical hole transport throughout the whole structure via tunneling. (C) 2002 Elsevier Science B.V. All rights reserved.