Solubility and dissolution kinetics of GaN in supercritical ammonia in presence of ammonoacidic and ammonobasic mineralizers

Schimmel S, Koch M, Macher P, Kimmel AC, Steigerwald T, Alt N, Schlücker E, Wellmann P (2017)


Publication Language: English

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2017

Journal

Publisher: Elsevier B.V.

Book Volume: 479

Pages Range: 59-66

DOI: 10.1016/j.jcrysgro.2017.09.027

Abstract

Solubility and dissolution kinetics of GaN are investigated, as they represent essential parameters for ammonothermal crystal growth of GaN. In situ X-ray imaging is applied to monitor the dissolving crystal. Both ammonoacidic and ammonobasic conditions are investigated. Compared to NH4F, the dissolution is generally much slower using NaN3 mineralizer, leading to a much longer time needed to establish a saturated solution. The solubility of GaN at 540 °C and 260 MPa in supercritical ammonia with a molar concentration
of NaN3 of 0.72 mmol/ml is determined to be 0.15 ± 0.01 mol%. This suggest a severe
refinement of raw gravimetric literature data also for alkali metal based mineralizers, as we reported previously for ammonium halide mineralizers. The order of magnitude is in good agreement with refined gravimetric solubility data (Griffiths et al., 2016). The apparent discrepancy between the literature and this work regarding the temperature range in which retrograde solubility occurs is discussed. A possible reason for the occurrence of retrograde solubility at high temperatures is described. The paper is complemented by a section pointing out and partially quantifying potential, reactor-material-dependent sources of errors.

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How to cite

APA:

Schimmel, S., Koch, M., Macher, P., Kimmel, A.-C., Steigerwald, T., Alt, N.,... Wellmann, P. (2017). Solubility and dissolution kinetics of GaN in supercritical ammonia in presence of ammonoacidic and ammonobasic mineralizers. Journal of Crystal Growth, 479, 59-66. https://dx.doi.org/10.1016/j.jcrysgro.2017.09.027

MLA:

Schimmel, Saskia, et al. "Solubility and dissolution kinetics of GaN in supercritical ammonia in presence of ammonoacidic and ammonobasic mineralizers." Journal of Crystal Growth 479 (2017): 59-66.

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