  Influence of Cd and Se atoms on the quantum efficiency of photon emission
through EL2 defects in gallium arsenide single crystals has been investigated.
A comparative technique of impurity diffusion in vacuum and arsenic atmospheres
has been used. The change character and extent of the photon emission quantum
efficiency have been established to be defined by vacancy structure of crystal
that is most likely caused by formation of EL2-dopant complexes.
