Photoluminescence of high-quality SiGe quantum wells grown by molecular beam epitaxy

Abstract
A variety of SiGe quantum well (QW) samples were grown by solid‐source molecular beam epitaxy (MBE) to study the influence of growth temperature TG and QW width Lz on the photoluminescence (PL) properties. For all growth temperatures investigated (350 °C≤TG≤750 °C) we found intense, well‐resolved PL signals from the SiGe QWs. The PL intensity increases with TG, and the stability against measurement temperature becomes better. A formerly reported PL band below the SiGe band edge is either completely absent, or very weak in the 4.2 K spectra of our samples. Thus, the defects or complexes responsible for this signal are obviously not inherent properties of MBE growth.