Three Solid Modifications of Ba[Ga(NHb>2b>)b>4b>]b>2b>: A Soluble Intermediate in Ammonothermal GaN Crystal Growth

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• 作者：Jan Hertrampf ; Nicolas S. A. Alt ; Eberhard Schl&uuml ; cker and Rainer Niewa
• 刊名：European Journal of Inorganic Chemistry
• 出版年：2017
• 出版时间：February 03, 2017
• 年：2017
• 卷：2017
• 期：5
• 页码：902-909
• 全文大小：2224K
• ISSN：1099-0682c

文摘

Ammonothermally grown GaN crystals are highly demanded as superior substrates for manufacturing high-performance blue and white LEDs. Ba or Ba(NHb>2b>)b>2b> can act as effective mineralizers under ammonothermal conditions (523 K, 110–150 MPa) and lead to the formation of barium bis(tetramidogallate), Ba[Ga(NHb>2b>)b>4b>]b>2b>, a new intermediate in h-GaN synthesis, which was obtained in three solid forms. Single crystals of all three modifications were characterized by X-ray diffraction techniques. Like earlier characterized intermediates in ammonobasic GaN crystal growth, all forms of Ba[Ga(NHb>2b>)b>4b>]b>2b> contain isolated [Ga(NHb>2b>)b>4b>]^– units. Differences between the forms originate in the coordination environments of Ba, leading to various frameworks with the [Ga(NHb>2b>)b>4b>]^– complex ions. Raman and IR spectroscopic data are discussed. Ba[Ga(NHb>2b>)b>4b>]b>2b> in an inert gas thermally decomposes in several steps to finally yield the intermetallic compound BaGab>2b>.