  A relationship between the chemical composition, structure and luminescent
properties of light-emitting SiOxNy(Si) composite layers with Si nanocrystals
is demonstrated. Photoluminescence (PL) with a maximum of intensity at 500-600
nm is observed in a narrow region of chemical compositions with relatively
small Si excess (about 10 at. %). Composite layers structure is studied by
means of HRTEM. Appearance of nanocrystals due to annealing is accompanied by
substantial growth (30-40 times) of PL intensity but do not change PL spectra
shape. Chemical composition of structural luminescent-active complexes with
excess Si atomes is determined by XPS technique.
