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

该项目的第二个资助期涉及扩展和进一步发展生长氮化物单晶的氨酸和氨碱工艺。在这种情况下，其他子项目的最新结果将应用于基本工艺，以便不仅获得超越最先进水平的优化工艺，而且获得对晶体生长过程中正在进行的工艺的综合看法。将评估无意杂质的来源和传输，并根据工艺参数和生长系统的化学成分检查它们在晶体中的结合情况。除了与实验工作直接相关的实验工作外，还将通过30个模拟来进一步研究流型和工艺参数对温度和流量分布的影响，这将有助于涉及到迄今文献中尚未考虑的影响。此外，将在第一阶段的新发现的基础上，建立一个单热系统的化学模型，该模型将解释以前未考虑的方面，如矿物质的背向输送或化学元素的分布。到目前为止，这样的模型还不存在。在项目后期，关于氮化物氨热合成的知识将转移到新的功能氮化物晶体的生长上。TP 1在第一阶段对氮化物化合物的研究表明，特别是纤锌矿结构的氮化物化合物是一种很有前途的氨热合成候选化合物。在关于中间体和新型矿化剂的子项目1和2的实验和研究的基础上，将重点关注半导体材料InN和Zn3N的生长，以及锌-IV-氮化锌三元化合物的生长，如锌硅氮、锌锗氮和锌锡氮的生长。到目前为止，这些材料还不能作为块状晶体材料生产。然而，这些化合物的高潜力有望替代现有的GaN、InN和AIN系统。因此，该项目将为访问新的材料系统铺平道路。

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.