Comparative analysis of light emitting properties of Si:Er and Ge/Si1-xGex epitaxial structures obtained by MBE method

We discuss the nature and the peculiarities of photoluminescence spectra from Si:Er and strained Ge/Si1-xGex structures obtained by the MBE method with sublimating Si sources and find out their common features and differences. We also discuss the mechanisms of photoluminescence in (0.75-0.85) eV region, which can be common for these structures and can be connected with light emission of oxygen complexes in layers. We consider difference ways to improve the light emitting properties of Si. It was shown by comparing single-crystal and porous Si:Er layers that electron low-dimensional effects in a porous system do not cause any observable Er-related properties in photoluminescence spectra. We compared the light emitting properties of Si:Er-O layers and oxygen impurity atmosphere in strong elastic stressed regions near misfit dislocations or Ge inclusions (islands) in Si1-xGex layers (Ge/Si1-xGex superlattices).