Si/Si1-xGex wires were grown by local solid source molecular beam epitaxy using three kinds of masks: Si, SiO2 and SiO2/Si3N4 Their structural properties were studied by transmission electron microscopy to obtain information on the shape of cross sections, and by high resolution X-ray coplanar diffraction, which yielded the average vertical and in-plane strain. Grazing incidence diffraction was used to measure the depth-dependent in-plane strain distribution in the wires as well as in the substrate, which is compared to results of finite element calculations. Low temperature photoluminescence measurements were performed to investigate the optical properties of the wires.