Growth of Solid Solutions (Ge2)1−x−y(GaAs1−δBiδ)x(ZnSe)y on Silicon Sub-strates by Liquid Phase Epitaxy

This paper investigates the possibility of growing solid solutions of the composition (Ge2)1−x−y(GaAs1−δBiδ)x(ZnSe)y on silicon substrates using a germanium (Ge) buffer layer. The optimal conditions for obtaining a structurally high-quality epitaxial layer have been determined. In the study, the solid solution was obtained by liquid-phase epitaxy from a bismuth-containing melt solution. Epitaxial growth was carried out in a palladiumpurified hydrogen atmosphere at a cooling rate of 1 ÷ 1.5°C/min in the temperature range 750 ÷ 650°C. Experimental data showed that the growth of the epitaxial film significantly depends on the size of the gap between the substrate and the starting material: the average symmetrical gap was 0.8 mm with a dispersion of 0.1 mm. Crystallisation occurred under the combined influence of diffusion and gravitational flow processes. Epitaxial films with a thickness of up to 10 µm demonstrated p-type conductivity with a specific resistance of about 10 Ω∙cm and a carrier concentration of 1.5 × 1016 cm−3 . At a temperature of 750°C, the formation of nanoclusters was observed, which is associated with a 4% mismatch in lattice parameters and a difference in the thermal expansion coefficients of the components. The solid solution (Ge2)1−x−y(GaAs1−δBiδ)x(ZnSe)y (at 0 ≤ x ≤ 0.53, 0 ≤ y ≤ 0.74) was characterised by a gradient composition. At a depth of 1 μm, the GaAs and ZnSe content did not exceed 15% and 12%, respectively

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