Intermediates during Ammonothermal Synthesis of Crystals of Binary and Higher Metal NitrideSemiconductor Materials

该子项目在第二个项目期间的主要目标是深化第一个项目期间获得的关于二元金属氮化物晶体的氨热合成化学机制的知识，并将该技术转移到进一步的化学系统中。通过（独立地）提高最高温度和压力以及进一步开发衬里材料，可以拓宽氨热条件下可能的实验范围。特别是在氨化条件下以钾酰胺作为矿化剂合成氮化镓的过程中，所获得的液体化合物的表征可能是理解晶体生长条件下特定化学过程的关键。这些研究将得到对氨基铝酸钠和氨基铝酸钾的研究的支持，因为根据文献，这些化合物显示出非常相似的化学性质，并且作为固体存在，更好地定义了起始材料。作为一个结果，我们期望进一步的重要信息，以解释氮化镓在sc-NH3中的温度和压力依赖的溶解度。相关的问题是与其他子项目合作，在晶体生长过程中，在原子/分子水平上对溶解物质和过程进行现场研究（TP 3,4,5）。生成精确的性质和溶解度数据是另一个重要的点（与所有tp合作）。对于新材料的生产，将首先对迄今未知的氨热合成半导体InN和Zn3N2中可能的中间体进行表征。根据获得的信息和先进的实验可能性，这些有趣的材料的晶体生长应该是成功的。接下来将进行氮化镓与氮化镓、过渡金属氮化物（如ScN）、稀土金属氮化物以及三元材料（如ZnSiN2、ZnGeN2和ZnSnN2与TP 1密切合作）的固溶体的合成。在这些情况下，对可溶性中间体的了解也是至关重要的。

The main goal of this subproject during the second project period is to deepen the knowledge about the chemical mechanisms in ammonothermal synthesis of binary metal nitride crystals acquired in the first period and to transfer the knowhow to further chemical systems. The spectrum of possible experiments under ammonothermal conditions shall be broadened via (independent) increase of maximal temperature and pressure as well as further development of liner materials.Particularly in the synthesis of GaN under ammonobasic conditions with potassium amide as mineralizer the characterization of the obtained liquid compound might be the key to the understanding of the specific chemical processes at crystal growth conditions. These investigations will be supported by studies of the sodium and potassium amido aluminates, since these compounds according to literature show a quite similar chemistry and present as solids better defined starting materials. As one result we expect further important information for the interpretation of the temperature and pressure dependent solubilities of GaN in sc-NH3 with ammonobasic mineralizers. Related issues are the in situ-studies of dissolved species and processes at the atomic/molecular level during the crystal growth in cooperation with other subprojects (TP 3, 4, 5). The generation of precise property and solubility data is a further important point (cooperation with all TPs).For the production of new materials first possible intermediates in the up to date unknown ammonothermal synthesis of the semiconductors InN and Zn3N2 will be characterized. Based on the obtained information and the advanced experimental possibilities the crystal growth of these interesting materials should be successful. In the following the synthesis of solid solutions of GaN with InN and with transition metal nitrides, e.g. ScN, and rare-earth metal nitrides,, as well as of ternary materials (e.g., ZnSiN2, ZnGeN2 und ZnSnN2 in close cooperation with TP 1) will be carried out. Also in these cases the knowledge of the soluble intermediates is of utmost importance.