Reactor materials and their role in ammonothermal growth of high-purity functional nitrides

Yazdihojatabadi S, Wostatek T, Schimmel S (2026)

Publication Language: English

Publication Type: Conference contribution, Abstract of a poster

Publication year: 2026

Event location: Karlsruhe, Germany DE

Abstract

Ammonothermal synthesis has emerged as a highly promising route towards

bulk single crystals of III-nitride semiconductors with low dislocation densities and

high structural quality, enabling next-generation optoelectronic and power

devices.1,2 Two Ni-based superalloys commonly used in ammonothermal crystal

growth and synthesis as reactor materials are Haynes 282 and Inconel 718.1,2

Building on the current status of ammonothermal GaN growth and defect

engineering, as well as on descriptions of ammonothermal chemistry and reactor

technology, this contribution addresses three key roles of the reactor material: (i)

its function as a load-bearing component that defines the accessible temperaturepressure

window via creep and strength2; (ii) its role as an impurity source

affecting unintentional doping and defect formation in the grown crystals; and (iii)

its interaction with oxygen as an effective getter that shapes the chemical

environment in supercritical ammonia. A literature-based analysis of alloy

properties and corrosion behaviour will be presented. In particular, the variability

of relevant mechanical properties of Ni-based superalloys will be analyzed,

including the implications for defining the maximum operating conditions of

ammonothermal autoclave components made of Haynes 282 and Inconel 718,

respectively.

Ultimately, the project aims to derive operating maps and crystal-growth

strategies for selected novel nitrides, accounting for thermodynamic stability and

reactor-material limitations. These considerations will guide future

ammonothermal experiments beyond GaN and support the selection of suitable

nitride systems, mineralizers, and reactor conditions for high-purity crystal growth.

Authors with CRIS profile

Thomas Wostatek Lehrstuhl für Elektronische Bauelemente Saskia Schimmel Lehrstuhl für Elektronische Bauelemente

Related research project(s)

Emmy Noether-Programme „Novel nitride materials for electronic devices“ (1st period of funding) Aug. 1, 2023 - July 31, 2026

How to cite

APA:

Yazdihojatabadi, S., Wostatek, T., & Schimmel, S. (2026, March). Reactor materials and their role in ammonothermal growth of high-purity functional nitrides. Poster presentation at 14th Annual jDGKK Meeting, Karlsruhe, Germany, DE.

MLA:

Yazdihojatabadi, Sajad, Thomas Wostatek, and Saskia Schimmel. "Reactor materials and their role in ammonothermal growth of high-purity functional nitrides." Presented at 14th Annual jDGKK Meeting, Karlsruhe, Germany 2026.

BibTeX: Download