Book: Ammonothermal Synthesis and Crystal Growth of Nitrides

Chapter: Equation of States and Ammonia Decomposition in Ammonothermal Systems

Author: Siddha Pimputkar

ISBN: 978-3-030-56304-2


Publisher: Springer

Chapter Description: The ammonothermal method is an under-explored synthesis method using supercritical ammonia as a solvent towards the synthesis of a broad range of nitride materials, for example gallium nitride (GaN). One of many outstanding mysteries of this approach is what is actually inside the autoclaves during synthesis. Pimputkar’s contribution to providing new insight into the process details a thermodynamic/theoretical exploration on how much ammonia is actually present in the system and did not decompose into inert hydrogen and nitrogen. Experimental data beautifully backs up the new model which is developed. Based on this investigation, there is no easy way around having to use high pressure (> 1000 atm) at elevated synthesis temperatures to prevent significant loss of the solvent, ammonia. Next steps: trying to understand and enhance the solubility of desired elements into the supercritical solution from a theoretical perspective. Stay tuned!

What are your research interests?: Pimputkar stated, “A focal area of my research is to find (new) approaches to synthesize nitrogen-containing materials (predominantly nitrides) in single crystal format. A significant challenge with these materials is the ease with which they decompose requiring specialized environments encouraging synthesis of these materials at temperatures below their decomposition temperature which is typically well below their melting temperature.  As such, solvent-based techniques using a variety of solvents are being explored to yield scientifically or technologically important materials which are then further investigated for their material properties and device applications.”

How did you get involved with this publication?: Pimputkar explains, “The German government sponsored a significant research effort across multiple universities for many years and this book is in effect their final report on their projects. Given the important contributions I have made to the field (independent of the German funding and research), they invited me to contribute to the book to make it a more comprehensive reference for people in the community.”