In situ atomic-resolution study of transformations in double polymorph ?/ß-Ga2O3 structures
Journal article, 2024

Disorder-induced formation of metastable Ga2O3 polymorphs as well as the recovery of the stable state upon annealing attract attention because of the fundamental novelty and rapidly increasing interest in the use of Ga2O3 in practical applications. In this study, double polymorph ?/ß-Ga2O3 structures fabricated by the radiation-induced disorder approach were used as a starting point for systematic in situ annealing electron microscopy experiments. We show that, under the conditions of the TEM in situ annealing, double ?/ß-Ga2O3 polymorph structures remained stable up to 300 °C, when onsets of the ?-to-ß transformation become traceable, leading to a prominent ?- and ß-mixture already at 500 °C. Interestingly, the recrystallization of the ß-Ga2O3 occurs throughout the whole ?-film and the preferential alignments at the newly emerging ?/ß-interfaces are different from that of the initial ?/ß-interface formed as a result of the disorder-induced ordering. The alignments of the two polymorphs are maintained as a function of temperature - with a reduction in the volumetric ratio of ?-domains for increasing annealing temperature. Finally, at 1100 °C, ?-Ga2O3 fully transforms into ß-Ga2O3, without dominating crystallographic relationships or preferred orientations, indicating that energy barriers are not any longer implied limiting factors, because of a sufficiently high thermal energy supply. Thus, these TEM in situ measurements enable a new level of accuracy for assessing polymorphic transformations in Ga2O3

Author

J. García-Fernández

University of Oslo

S. B. Kjeldby

University of Oslo

Lunjie Zeng

Chalmers, Physics, Nano and Biophysics

A. Azarov

University of Oslo

A. Pokle

University of Oslo

P. D. Nguyen

University of Oslo

Eva Olsson

Chalmers, Physics, Nano and Biophysics

Lasse Vines

University of Oslo

Andrej Yu Kuznetsov

University of Oslo

O. Prytz

University of Oslo

Materials Advances

26335409 (eISSN)

Vol. 5 9 3824-3831

Subject Categories

Condensed Matter Physics

DOI

10.1039/d3ma01011b

More information

Latest update

5/25/2024