alpha-Ga2O3 grown by low temperature atomic layer deposition on sapphire

Roberts, JW, Jarman, JC, Johnstone, DN, Midgley, PA, Chalker, PR ORCID: 0000-0002-2295-6332, Oliver, RA and Massabuau, FC-P
(2018) alpha-Ga2O3 grown by low temperature atomic layer deposition on sapphire. JOURNAL OF CRYSTAL GROWTH, 487. pp. 23-27.

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α-Ga2O3 is a metastable phase of Ga2O3 of interest for wide bandgap engineering since it is isostructural with α-In2O3 and α-Al2O3. α-Ga2O3 is generally synthesised under high pressure (several GPa) or relatively high temperature (∼500 °C). In this study, we report the growth of α-Ga2O3 by low temperature atomic layer deposition (ALD) on sapphire substrate. The film was grown at a rate of 0.48 Å/cycle, and predominantly consists of α-Ga2O3 in the form of (0001)-oriented columns originating from the interface with the substrate. Some inclusions were also present, typically at the tips of the α phase columns and most likely comprising ε-Ga2O3. The remainder of the Ga2O3 film – i.e. nearer the surface and between the α-Ga2O3 columns, was amorphous. The film was found to be highly resistive, as is expected for undoped material. This study demonstrates that α-Ga2O3 films can be grown by low temperature ALD and suggests the possibility of a new range of ultraviolet optoelectronic and power devices grown by ALD. The study also shows that scanning electron diffraction is a powerful technique to identify the different polymorphs of Ga2O3 present in multiphase samples.

Item Type: Article
Uncontrolled Keywords: Semiconducting gallium compounds, Oxides, Atomic layer epitaxy, X-ray diffraction, Scanning electron diffraction
Depositing User: Symplectic Admin
Date Deposited: 21 Feb 2020 13:54
Last Modified: 19 Jan 2023 00:01
DOI: 10.1016/j.jcrysgro.2018.02.014
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