Intermediates during the Formation of GaN under Ammonothermal Conditions

Gallium nitride as a binary compound semiconductor is featuring wide band-gap and high thermal conductivity which make it a potential material for optoelectronic devices operating within an energy spectrum from blue to ultraviolet region and high performance RF microdevices. Attracted by the wide applications and bright prospect of gallium nitride materials in nowadays semiconductor industry, extensive research has been directed to developing and optimizing GaN single crystal growth techniques.

Ammonothermal method, allowing the growth of crystals in supercritical ammonia, is widely believed to be a promising route towards excellent bulk GaN crystals. Besides the crucial synthesis parameters such as temperature and pressure, the selection of different mineralizers is playing an important role in ammonothermal crystal growth as well. Both acidic (ammonium halides) and basic mineralizers (alkali metal amides) are commonly utilized to enhance the solubility of GaN in supercritical ammonia by the formation of soluble intermediate species.

Scientific works presented in this dissertation focus on the studies of Ga-containing ammoniate and amide compounds obtained from liquid and supercritical ammonia, which might possibly be involved in the ammonothermal growth of GaN with use of different mineralizers. As a part of the ongoing FOR-1600 project, the researches are aimed at a deeper understanding of the GaN ammonothermal growth process and roviding a foundation for developing the optimal process parameters in future.