Crystal Growth of nitride single crystals of high purity with the ammonothermal method

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The second funding period of this project deals with the extension and further development of the ammonoacidic and ammonobasic process for the growth of nitride single crystals. In this context , the recent results of the other subprojects will be applied to the basic processes in order to not only get an optimized process beyond state of the art, but to get an integrated view of the ongoing processes during crystal growth. The sources and transport of unintentional impurities will be evaluated and their incorporation into the crystals depending on the process parameters and the chemistry of the growth system are examined. In addition to the experimental work and directly related thereto, the flow pattern and the influence of the process parameters on the temperature and flow distribution will be further investigated with 30 simulations, which will help to involve so far in literature unconsidered effects. Moreover, a chemical model of the ammonothermal system will be developed, based on the new finding from period one, which will account for previously unconsiderd aspects like back transportation of the mineralizes or distribution of chemical spezies. Such a model does not exist so far.Later on in the project, the obtained knowledge with regard to the ammonothermal synthesis of nitrides will be transferred to the growth of new functional nitride crystals . The studies of nitride compounds performed in the first period by TP 1, revealed that especially such compounds with a Wurtzite-type structure are very promising candidates for an ammonothermal synthesis . Based on the experiments and investigations of the subprojects 1 and 2 concerning intermediates and new mineralizers, the growth of the semiconductor materials lnN and Zn3N2 and of the ternary Zinc-IV-nitr ides, like ZnSiN2 , ZnGeN2 , and ZnSnN2 , will be targeted . These materials could not be produced as bulk crystalline material so far. However, a high potential of these compounds could be expected as a alternative to the existing GaN, lnN, and AIN system. So the project will path the way to access a new material system.