The system of triple In1–xGaxAs continuous solid solutions allows the solution of the many problems of modern semiconductor technology as microelectronics, optoelectronics, and nanoelectronics. The remarkable manufactural properties of ternary In1-XGaXAs solid solutions make them very useful nanotech performance materials for manufacture nanotech products, such as nanowires, nanotubes, etc. For successful solution of this problem, it is necessary to reveal their intrinsic properties and eliminate the effect of structural imperfections existing in thin films and layers, which is possible by investigating crystals of In1–xGaxAs solid solutions in bulk form. The complete miscibility of components in the solid and liquid state and the linear dependence of lattice parameter on the composition of In1–xGaxAs solid solutions allow to consider this system as a pseudo-binary alloys system of two components of (GaAs)x and (InAs)1–x like SiGe alloys system. This feature of the alloys has enabled to apply the comparatively affordable and straightforward method of direct fusion process of InAs and GaAs components for producing of In1–xGaxAs alloys with stable chemical composition. Carefully selected conditions of the fusion and processing of crystal growth have allowed obtaining several compositions of InAs-rich In1–xGaxAs alloys with uniform distribution of components across the ingot of single crystal by one fusion.