FEATURES OF LIQUID-PHASE EPITAXY OF (GaAs)1-x(ZnSe)x SOLID SOLUTION FROM THE TIN SOLUTION-MELT

Layers of (GaAs)1-x(ZnSe)x (0 x 0.80) molecular substitution solid solutions with a smoothly (but not monotonically) varying composition on monocrystal GaAs (100) substrates were grown by liquid-phase epitaxy from a limited volume of a tin solution-melt. Based on the results of the solubility of GaAs, ZnSe in tin and the phase diagram of binary systems Ga-Sn, As-Sn, Zn-Sn and Sn-Se, it is shown that binary compounds in the tin solvent at temperatures of 650-750°C are below the melting point of the corresponding materials are found mainly in the form of GaAs and ZnSe molecules. Moreover, in the temperature range 650-750C, the solubility of GaAs in tin varies from ~ 2.6 to ~ 5.5 mol%, and ZnSe - from ~ 0.2 to ~ 0.35 mol%, the solubility of gallium and zinc is unlimited, and the solubility of arsenic is more than 70 at.%, selenium - more than 5 at.%. It is shown that due to the difference in the valence of gallium and arsenic atoms, the forces of chemical bonds between neighboring Ga and As atoms located in the tetrahedral lattice are not the same. In the tetrahedral lattice, each Ga atom forms 4 bonds with four neighboring As atoms, three of which are formed by the sharing of electrons of neighboring Ga and As atoms, and the fourth one only due to the two valence electrons of the As atom. Apparently, the ionic fraction of the fourth chemical bond is stronger than the other three