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Three Solid Modifications of Ba[Ga(NH 2 ) 4 ] 2 : A Soluble Intermediate in Ammonothermal GaN Crystal Growth
Author(s) -
Hertrampf Jan,
Alt Nicolas S. A.,
Schlücker Eberhard,
Niewa Rainer
Publication year - 2017
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201601342
Subject(s) - chemistry , crystallography , yield (engineering) , raman spectroscopy , barium , intermetallic , crystal structure , x ray crystallography , crystal (programming language) , crystal growth , ion , gallium , diffraction , inorganic chemistry , materials science , metallurgy , organic chemistry , programming language , physics , alloy , computer science , optics
Ammonothermally grown GaN crystals are highly demanded as superior substrates for manufacturing high‐performance blue and white LEDs. Ba or Ba(NH 2 ) 2 can act as effective mineralizers under ammonothermal conditions (523 K, 110–150 MPa) and lead to the formation of barium bis(tetramidogallate), Ba[Ga(NH 2 ) 4 ] 2 , 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(NH 2 ) 4 ] 2 contain isolated [Ga(NH 2 ) 4 ] – units. Differences between the forms originate in the coordination environments of Ba, leading to various frameworks with the [Ga(NH 2 ) 4 ] – complex ions. Raman and IR spectroscopic data are discussed. Ba[Ga(NH 2 ) 4 ] 2 in an inert gas thermally decomposes in several steps to finally yield the intermetallic compound BaGa 2 .