Investigation of dissolution- and crystrallization equilibria as a basis for the ammonothermal crystalgrowth of nitrides

研究溶解和结晶平衡作为氮化物氨热晶体生长的基础

• 批准号: 201468004
• 负责人: Professor Dr. Wilhelm Schwieger
• 金额: --
• 依托单位: Lehrstuhl für Chemische Reaktionstechnik (CRT)
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/201468004?language=en
• 关键词: Investigation; dissolution; crystrallization; equilibria; basis

The knowledge on the solubility of GaN in ammonothermal synthesis is a crucial prerequisite to understand and control the process as well as to optimize the operating conditions. In order to generate the solubility data and to obtain the optimal conditions for the ammonothermal process four different systems available in the second funding period: (i) In the first phase, an experimental set-up was built with six autoclaves having a possibility of autoclave filling station and three heating ovens with three zones for different synthesis functions. With this experimental set-up, solubility measurements under uniform heating conditions and the crystallization experiments with a temperature gradient along the length of autoclave are being performed in collaboration with TP 3, 6 and Z. (ii) A prototype double reactor consists of two autoclaves was designed to understand the sampling technique and to improve the optimization of the process. In the second period of the project, com-prehensive solubility measurements will be performed by collecting the samples from the double reactor and analyzing through ex situ characterization methods. (iii) In the second period of the project, the above-mentioned double reactor will be upgraded to multiple reactors with the integration of more sampling reactors to understand the crystallization kinetics. Mass balance of the ammonothermal process and the characterization of the products will be performed through this multiple reactor sampling and ex situ characterization methods, respectively. (iv) To the best of our knowledge, for the first time we will determine the solubility of GaN and the density of the supercritical ammonia using in situ measurement of ultrasonic velocity. In addition, knowledge on the crystallization kinetics will be obtained through this in situ ultrasonic method.

了解GaN在氨合成中的溶解度是理解和控制该过程以及优化操作条件的重要前提。为了生成溶解度数据并获得氨化工艺的最佳条件，在第二个供资期内提供了四种不同的系统：（i）在第一阶段，建立了一个实验装置，其中有六个高压釜，可能有高压釜灌装站和三个加热炉，三个加热炉有三个区域，用于不同的合成功能。采用该实验装置，与TP 3、6和Z合作，在均匀加热条件下进行溶解度测量，并在沿高压釜长度沿着设置温度梯度的情况下进行结晶实验。(ii)设计了一个由两个高压釜组成的原型双反应器，以了解取样技术和改进过程的优化。在项目的第二阶段，将通过从双反应器中收集样品并通过非原位表征方法进行分析来进行综合溶解度测量。(iii)在项目的第二阶段，上述双反应器将升级为多反应器，并集成更多的取样反应器，以了解结晶动力学。氨合成工艺的质量平衡和产品的表征将分别通过这种多反应器取样和非原位表征方法进行。(iv)据我们所知，我们将首次使用超声波速度的原位测量来确定GaN的溶解度和超临界氨的密度。此外，结晶动力学的知识将通过这种原位超声方法获得。