Synthesis of Bulk GaN Single Crystals Using Na-Ca Flux

Abstract

We grew GaN single crystals in Na–Ca flux and found that the presence of Ca in a high-temperature flux system has the following advantages for growing GaN single crystals. First, Ca in solution drastically increased the yield of GaN crystals. Second, transparent GaN single crystals are easy to grow around the gas-liquid interface. Third, the pressure required to synthesize the GaN is reduced. These effects can be interpreted as resulting from increased nitrogen solubility in the flux. In this paper, we report the effects of Ca on the yield of GaN and threshold pressure for growing GaN in Na–Ca flux.