Method for production of zinc oxide single crystals

A method for growing a zinc oxide (ZnO) single crystal boule within an interior of a physical vapor transport (PVT) furnace system, the method comprising the steps of:

• placing a ZnO source material inside a first end of an iridium metal crucible and placing a ZnO seed in a second end of the iridium metal crucible wherein the ZnO seed and a surface of the ZnO source material facing the ZnO seed are separated by a first distance;
• placing the iridium metal crucible containing the ZnO seed and the ZnO source material in a thermal insulation setup;
• heating the iridium metal crucible containing the ZnO seed and the ZnO source material to obtain a temperature distribution such that a temperature of the ZnO source material (T1), is higher than a temperature of the ZnO seed (T2), wherein T2 is a temperature in a range from about 1500° C. to about 1900° C.;
• maintaining a pressure of the interior of the PVT furnace system by flowing a gas mixture through the interior of the PVT furnace system;
• and
• maintaining the temperature distribution within the iridium metal crucible to cause growth of the ZnO single crystal boule on the ZnO seed, wherein the ZnO crystal boule comprises lithium (Li) in an atomic concentration less than about 1×1016 cm−3and hydrogen (H) in an atomic concentration less than about 1×1017 cm−3.