Devices and methods for growing crystals

A method for growing a seed crystal, comprising:

• obtaining a plurality of orthohexagonal seed crystals in a hexagonal crystal system by performing a first cutting on a plurality of seed crystals in the hexagonal crystal system to be expanded, respectively, wherein cutting faces of the plurality of orthohexagonal seed crystals correspond to a same lattice plane family;
• splicing the plurality of orthohexagonal seed crystals in the hexagonal crystal system;
• obtaining a seed crystal in the hexagonal crystal system to be grown by performing a second cutting on the plurality of spliced orthohexagonal seed crystals in the hexagonal crystal system;
• obtaining an intermediate seed crystal in the hexagonal crystal system by performing a gap growth on the seed crystal in the hexagonal crystal system to be grown under a first setting condition;
• and
• obtaining a target seed crystal in the hexagonal crystal system by performing an epitaxial growth on the intermediate seed crystal in the hexagonal crystal system under a second setting condition, wherein
• a diameter of the target seed crystal in the hexagonal crystal system is larger than a diameter of the seed crystals in the hexagonal crystal system to be expanded.