In the field of material synthesis, novel semiconductor materials and crystallization processes are being developed for electronic, photonic, and acoustic applications.

Research focus

One focus is on the synthesis of nitride materials, including ammonothermal crystal growth, in which supercritical ammonia is used to produce high-quality single crystals and substrate materials. Materials and process engineering approaches to crystal growth and the targeted adjustment of structural, chemical, and functional properties are also the subject of research, as are the necessary technological and methodological developments, which are of great importance due to the challenging conditions of the ammonothermal process. A central element is therefore the development and use of advanced high-pressure technologies, including X-ray-based and optical in-situ measurement methods, which enable direct, quantitative observation of solution, transport, and crystallization processes under real process conditions. Through the close linking of material synthesis, in situ monitoring, and process-scientific analysis, the underlying chemical-physical mechanisms are systematically elucidated, the reproducibility of experimental processes is improved, and the development of new material systems that can be integrated with established III-nitride technologies is specifically advanced.

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Current research topics:

• Ammonothermal crystal growth of binary and ternary III-nitrides – control of conductivity and stoichiometry (Thomas Wostatek)
• Fundamentals of ammonothermal growth of nitride crystals – dissolution, transport, and crystallization (Rajesh Chirala)
• Adjustment of the piezoelectric and ferroelectric properties of III nitrides by alloying with metal nitrides – crystallization from N₂ and NH₃-based solutions and gas phases with the support of atomistic simulations (project within the priority program Nitrides4Future, currently being developed)

These topics are also the main research areas of the Nitride Semiconductors Working Group headed by Dr. Saskia Schimmel.

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