SiGe-based photodetectors operating at 1.3 mum are highly desirable for the development of optical interconnections on Sol substrates. We have therefore investigated the structural and optical properties of high Ge concentration Si/SiGe multi-quantum wells (MQWs) grown using a production-compatible reduced pressure-chemical vapor deposition system. The structures are designed in order to obtain dislocation-free strained SiGe layers with a band gap as low as possible. Those SiGe layers will be used as the absorbing layers in a future photodetector. Photoluminescence (PL) and X-ray. diffraction are used to determine the characteristics of our MQWs and verify the strain state of the layers in the stack. Atomic force microscopy and transmission electronic microscopy enabled us to check the structural properties of such heterostructures. A PL emission corresponding to the free exciton "no phonon" transition as low as 0.895 eV at 9 K was obtained, implying that strained Si/SiGe MQWs can be produced with a band gap as low as 0.845 eV at 300 K. (C) 2003 Elsevier Science B.V. All rights reserved.