Growth of bulk GaN crystals by Na flux method

High-quality and low cost bulk crystals are needed in the field of group III nitride semiconductors in order to develop optical and electrical devices. There are two approaches for the growth of bulk GaN crystal by the Na flux method. One is to grow thick GaN crystal on a seed GaN crystal grown by vapour phase method. The other one is to grow GaN crystal on the seed GaN crystal obtained by spontaneous nucleation. The both methods show advantages and disadvantages, respectively. We also present the effects of the flux composition on the growth habit and the growth rate for fabrication of boule-shape bulk GaN crystals. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim