AbstractThe electrical properties of GaAs epilayers doped with donor impurities Te and Sn during LPE from mixed Ga  Bi melts in temperature intervals from 850 to 820 °C and from 700 to 630 °C were investigated. The analysis of incorporation of Te and Sn into crystallizing GaAs considering preliminary association of impurity and compound component atoms in the liquid agree satisfactory with experimental data providing the presence of additional concentration of nonequilibrium arsenic vacancies on the (111)B surface of growing layer, which is not conditioned by activity of compound components in the liquid. It is shown that the main factor, determining the incorporation of donor impurities Te and Sn into GaAs during epitaxy from mixed Ga  Bi solvents, is the change of Ga and As concentrations ratio in the l