Low temperature growth and optical properties of alpha-Ga2O3 deposited on sapphire by plasma enhanced atomic layer deposition

Roberts, JW, Chalker, PR ORCID: 0000-0002-2295-6332, Ding, B, Oliver, RA, Gibbon, JT, Jones, LAH ORCID: 0000-0002-4654-3882, Dhanak, VR ORCID: 0000-0001-8053-654X, Phillips, LJ ORCID: 0000-0001-5181-1565, Major, JD ORCID: 0000-0002-5554-1985 and Massabuau, FC-P (2019) Low temperature growth and optical properties of alpha-Ga2O3 deposited on sapphire by plasma enhanced atomic layer deposition JOURNAL OF CRYSTAL GROWTH, 528. p. 125254. ISSN 0022-0248, 1873-5002

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Abstract

Plasma enhanced atomic layer deposition was used to deposit thin films of Ga<inf>2</inf>O<inf>3</inf> on to c-plane sapphire substrates using triethylgallium and O<inf>2</inf> plasma. The influence of substrate temperature and plasma processing parameters on the resultant crystallinity and optical properties of the Ga<inf>2</inf>O<inf>3</inf> films were investigated. The deposition temperature was found to have a significant effect on the film crystallinity. At temperatures below 200 °C amorphous Ga<inf>2</inf>O<inf>3</inf> films were deposited. Between 250 °C and 350 °C the films became predominantly α-Ga<inf>2</inf>O<inf>3</inf>. Above 350 °C the deposited films showed a mixture of α-Ga<inf>2</inf>O<inf>3</inf> and ε-Ga<inf>2</inf>O<inf>3</inf> phases. Plasma power and O<inf>2</inf> flow rate were observed to have less influence over the resultant phases present in the films. However, both parameters could be tuned to alter the strain of the film. Ultraviolet transmittance measurements on the Ga<inf>2</inf>O<inf>3</inf> films showed that the bandgaps ranges from 5.0 eV to 5.2 eV with the largest bandgap of 5.2 eV occurring for the α-Ga<inf>2</inf>O<inf>3</inf> phase deposited at 250 °C.

Item Type:	Article
Additional Information:	11 pages, 7 figures, 1 table
Uncontrolled Keywords:	Characterization, Crystal structure, Crystal morphology, X-ray diffraction, Atomic layer epitaxy, Gallium compounds
Depositing User:	Symplectic Admin
Date Deposited:	28 Aug 2019 15:31
Last Modified:	24 Jan 2026 02:06
DOI:	10.1016/j.jcrysgro.2019.125254
Related Websites:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3052627
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