Properties of the GaAs epilayers grown from ytterbium or scandium doping melts

The photoluminescence, electrical and X-ray (including an X-ray quasi-forbidden reflection) measurements were carried out for studying the influence of Yb or Sc concentration in Ga melt on electronic and structural properties of epilayers. It was shown that at the first stage (low concentration), the main role of Yb and Sc is a gettering of residual impurities in the melt. At the same time, they influence as ' catalysts ' which displace a heterogeneous equilibrium with changing the stoichiometry (increasing VGa). For the next stage of the increasing the concentration of these elements in melts, they begin to enter to enter in a Ga-sublattice and coagulate with deviation from the stoichiometry. There exists the optimum concentration of Yb and Sc when can get high-purity and stoichiometric epilayers for a device application