In situ X-ray monitoring of transport and chemistry of Ga-containing intermediates under ammonothermal growth conditions of GaN

Schimmel S, Duchstein P, Steigerwald T, Kimmel AC, Schlücker E, Zahn D, Niewa R, Wellmann P (2018)


Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2018

Journal

Publisher: Elsevier B.V.

Book Volume: 498

Pages Range: 214-223

DOI: 10.1016/j.jcrysgro.2018.06.024

Abstract

Formation and transport of Ga-containing intermediates are essential for ammonothermal bulk growth of GaN. In this work, in situ X-ray transmission measurements are established as a tool for monitoring face-selective dissolution of GaN crystals as well as the Ga-concentration in the fluid. The accuracy of concentration determination by X-ray transmission measurements is evaluated and the detection limit for dissolved species is estimated. The detection limit is given both as a gallium concentration and as an attenuation coefficient, thus, it can easily be transferred to other materials of interest. Face-selective ammonothermal etching is investigated for both ammonoacidic and ammonobasic mineralizers. Time- and space-resolved monitoring of the concentration of Ga-containing intermediates is demonstrated using NH4F mineralizer. The results are discussed with respect to the formation of Ga-containing intermediates and mechanisms of mass transport. Based on molecular dynamics simulations, the experimentally observed, unexpectedly low diffusion coefficient for the Ga-transporting species is ascribed at least partially to the diffusion of larger [GaxFy]3x−y aggregates.

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APA:

Schimmel, S., Duchstein, P., Steigerwald, T., Kimmel, A.-C., Schlücker, E., Zahn, D.,... Wellmann, P. (2018). In situ X-ray monitoring of transport and chemistry of Ga-containing intermediates under ammonothermal growth conditions of GaN. Journal of Crystal Growth, 498, 214-223. https://dx.doi.org/10.1016/j.jcrysgro.2018.06.024

MLA:

Schimmel, Saskia, et al. "In situ X-ray monitoring of transport and chemistry of Ga-containing intermediates under ammonothermal growth conditions of GaN." Journal of Crystal Growth 498 (2018): 214-223.

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