Interface formation of Al2O3 on n‐GaN(0001): Photoelectron spectroscopy studies |
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Authors: | Rafa Lewandk w,Mi osz Grodzicki,Piotr Mazur,Antoni Ciszewski |
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Affiliation: | Rafał Lewandków,Miłosz Grodzicki,Piotr Mazur,Antoni Ciszewski |
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Abstract: | Al2O3 insulator layers were deposited step by step by the physical vapor deposition (PVD) method onto gallium nitride in the wurtzite form, n‐type and (0001)‐oriented. The substrate surface and the early stages of Al2O3/n‐GaN(0001) interface formation were characterized in situ under ultra‐high vacuum conditions by X‐ray and ultraviolet photoelectron spectroscopy (XPS, UPS). The electron affinity (EA) of the substrate cleaned by annealing was 3.6 eV. Binding energies of the Al 2p (76.0 eV) and the O 1s (532.9 eV) confirmed the creation of the Al2O3 compound in the deposited film for which the EA was 1.6 eV. The Al2O3 film was found to be amorphous with a bandgap of 6.9 eV determined from the O 1s loss feature. As a result, the calculated Al2O3/n‐GaN(0001) valence band offset (VBO) is ?1.3 eV and the corresponding conduction band offset (CBO) 2.2 eV. |
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Keywords: | Al2O3 thin films, Al2O3/n‐GaN interface n‐GaN photoelectron spectroscopy semiconductor valence band |
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