Method for making transition metal dichalcogenide crystal

A method of making a transition metal dichalcogenide crystal having a chemical formula represented as MX2, wherein M represents a central transition metal element, and X represents a chalcogen element, comprising:

• providing MX2 polycrystalline powder, MX2 seed crystals, and a transport medium;
• providing a first reaction chamber defining an opening at one end of the first reaction chamber, wherein the MX2 polycrystalline powder and the transport medium are placed in the first reaction chamber;
• and
• providing a second reaction chamber comprising a source end and a deposition end opposite to the source end, wherein the first reaction chamber and the MX2 seed crystals are placed in the second reaction chamber, the first reaction chamber is placed at the source end, and the MX2 seed crystals are placed at the deposition end.