Crystalline silicon single quantum wells (QWs) were fabricated by high temperature thermal oxidation of ELTRAN® (Epitaxial Layer TRANsfer) silicon-on-insulator (SOI) wafers. The Si layer thicknesses enclosed by thermal SiO2 range from 0.8 to 5nm. Luminescence energies from ELTRAN QWs vary from 700nm (1.77eV) to 920nm (1.35eV) depending on the Si layer thickness, without evidence for the interface-mediated transitions observed in earlier reported work. The ability to detect quantum confined luminescence seems to arise from the use of ELTRAN SOI wafers, from suppressed interface state luminescence by high temperature oxidation and, possibly, from interface matching by crystalline silicon oxide. In contrast, SOI wafers prepared by the SIMOX (Separation by IMplantation of OXygen) process showed strong interface mediated features.