Optical and interfacial characteristics of a heterojunction between (2¯01)-oriented single-domain β-(In0.072Ga0.928)2O3 and α-Al2O3 crystals

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Abstract

In this article, we determine the band alignment at the thermodynamically stable heterointerface between a (2¯01)-oriented single-domain β-(In0.072Ga0.928)2O3 crystal and bulk c-plane sapphire, namely, (0001)-oriented α-Al2O3. The β-(In0.072Ga0.928)2O3 layer was deposited on the bulk sapphire crystal using pulsed laser deposition. The β-(In0.072Ga0.928)2O3 and α-Al2O3 valence and conduction band offsets (VBO and CBO, respectively) were found to be 0 ± 0.1 and 4.87 ± 0.1 eV, respectively. Accordingly, we identified a type-I α-Al2O3/β-(In0.072Ga0.928)2O3 heterojunction. X-ray diffraction measurements confirmed (2¯01)-oriented single-domain β-(In0.072Ga0.928)2O3 high-quality films with in-plane rotations of every 120∘, whereas Rutherford backscattering spectrometry was employed to verify the bulk composition. We employed high-resolution X-ray photoelectron spectroscopy to measure the core level binding energies of Al 2p and Ga 2p3/2 with respect to the valence band maxima of the β-(In0.072Ga0.928)2O3 and α-Al2O3 layers, respectively. Then, we measured the energy separation between the Al 2p and Ga 2p3/2 core levels at the interface of the heterojunction. β-(InGa)2O3 is a wide-bandgap semiconductor, while α-Al2O3 is a well-known dielectric. Together, they can be employed to fabricate reliable and efficient power electronic devices. We also combined high-resolution transmission electron microscopy, X-ray diffraction, and fast Fourier transform algorithms to characterize the dislocations at the interface.
Original languageEnglish (US)
Pages (from-to)3273
JournalOptical Materials Express
Volume12
Issue number8
DOIs
StatePublished - Aug 1 2022

Bibliographical note

KAUST Repository Item: Exported on 2022-09-14
Acknowledged KAUST grant number(s): BAS/1/1614-01-01
Acknowledgements: King Abdullah University of Science and Technology (BAS/1/1614-01-01). The authors acknowledge the access of the Nanofabrication Core Lab as well as the Imaging and Characterization Core Lab facilities at KAUST. N. A. acknowledges the support of the Ibn Rushd Postdoctoral Fellowship Program, administered by the King Abdullah University of Science and Technology (KAUST).

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

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