Tin gallium oxide epilayers on different substrates : optical and compositional analysis

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Hunter, Daniel A. and Naresh-Kumar, Gunasekar and Edwards, Paul R. and Makydonska, Olha and Massabuau, Fabien C. P. and Hatipoglu, Isa and Mukhopadhyay, Partha and Schoenfeld, Winston V. and Martin, Robert W. (2024) Tin gallium oxide epilayers on different substrates : optical and compositional analysis. Physica Status Solidi B, 261 (10). 2400137. ISSN 0370-1972 (https://doi.org/10.1002/pssb.202400137)

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Abstract

Electron beam techniques have been used to analyze the impact of substrate choice and growth parameters on the compositional and optical properties of tin gallium oxide [(Sn x Ga1−x)2O3] thin films grown by plasma‐assisted molecular beam epitaxy. Sn incorporation and film quality are found to be highly dependent on growth temperature and substrate material (silicon, sapphire, and bulk Ga2O3) with alloy concentrations varying up to an x value of 0.11. Room temperature cathodoluminescence spectra show the Sn alloying suppressing UV (3.3–3.0 eV), enhancing blue (2.8–2.4 eV), and generating green (2.4–2.0 eV) emission, indicative of the introduction of a high density of gallium vacancies (VGa) and subsequent VGa–Sn complexes. This behavior was further analyzed by mapping composition and luminescence across a cross section. Compared to Ga2O3, the spectral bands show a clear redshift due to bandgap reduction, confirmed by optical transmission measurements. The results show promise that the bandgap of gallium oxide can successfully be reduced through Sn alloying and used for bandgap engineering within UV optoelectronic devices.

ORCID iDs

Hunter, Daniel A., Naresh-Kumar, Gunasekar ORCID logoORCID: https://orcid.org/0000-0002-9642-8137, Edwards, Paul R. ORCID logoORCID: https://orcid.org/0000-0001-7671-7698, Makydonska, Olha, Massabuau, Fabien C. P. ORCID logoORCID: https://orcid.org/0000-0003-1008-1652, Hatipoglu, Isa, Mukhopadhyay, Partha, Schoenfeld, Winston V. and Martin, Robert W. ORCID logoORCID: https://orcid.org/0000-0002-6119-764X;
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