Inductively heated Bridgman method for the growth of zinc oxide single crystals

A Bridgman method using induction heating has been developed for growing zinc oxide crystals. Bulk single crystals were prepared in an iridium crucible, where the crucible is directly heated via eddy currents. A high-pressure vessel was used in order to suppress evaporation at the melting point and a carbon dioxide atmosphere is applied to prevent decomposition. Typically, single crystals of 33 mm in diameter and 40 mm in length have been obtained. The as-grown boules exhibit different transmission properties dependent on the purity of the starting material as well as the cooling rate after crystallization.