The GaAs-(Ge2)1−x–y(GaAs)x(ZnSe)y structure was obtained by liquid-phase epitaxy in a single technological cycle from a tin melt solution in the temperature range of 1023–893 K. The experimentally determined values of the mismatch between the lattice parameters of the substrate and the film (η = 0.04%) and the values of the distances between dislocations (L = 1.126 × 10–6 m) in the film showed its potential in obtaining crystalline perfect solid solutions and heterostructures based on them. The thickness of the pseudomorphic film layer was df = 0.48 μm. The value of the surface potential energy (W = 0.97 mJ/m2) in the substrate–film contact indicated the possibility of ordered growth of the components of the epitaxial layers (Ge2)1−x−y(GaAs)x(ZnSe)y on the GaAs (100) substrate. Low values of residual stresses in the film structure are associated with their partial relaxation due to differences between the lattice parameters and thermal expansion coefficients of the substrate and film. The measured electrophysical parameters indicate the possibility of using the obtained epitaxial layers in semiconductor instrument making.