Abstract <p>The effect of concentration supercooling on the structure of GaInAsSbP/GaP heterostructures grown by the method of zone recrystallization by a temperature gradient is investigated. The main technological parameters of the growth process are revealed, and the value of the initial concentration supercooling of the solution–melt is determined, which is necessary to establish a crystallization regime that prevents thermal degradation of the substrate and eliminates the possibility of capturing microinclusions of the solution–melt. The dependence of the mismatch of the lattice parameters of the GaP substrate and the GaInAsSbP layer on the initial supercooling is found.</p>