Characterization of pseudomorphic γ-Ga2O3 and γ-Al2O3 films on MgAl2O4 substrates and the band-alignment at the coherent γ-Ga2O3/Al2O3 heterojunction interface

• Published in: Japanese Journal of Applied Physics Vol. 58; no. 6; pp. 060910 - 60914
• Main Authors: Oshima, Takayoshi, Kato, Yuji, Magome, Eisuke, Kobayashi, Eiichi, Takahashi, Kazutoshi
• Format: Journal Article
• Language: English
• Published: Tokyo IOP Publishing 01.06.2019; Japanese Journal of Applied Physics
• Subjects: Alignment; Aluminum oxide; Conduction bands; Electrons; Gallium oxides; Heterojunctions; Heterostructures; Offsets; Photoelectrons; Substrates; Transitional aluminas; X-ray diffraction
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/1347-4065/ab219f

We characterized 3.0 nm γ-Ga2O3, 3.0 nm γ-Al2O3, and 1.0/3.0 nm γ-Ga2O3/Al2O3 films grown on (100) MgAl2O4 substrates. X-ray diffraction measurements revealed that γ-Ga2O3 and γ-Al2O3 films were coherent to the substrate with Poisson's ratios of 0.31 and 0.28. While, X-ray photoelectron spectroscopy found that band gaps of the γ-Ga2O3 and γ-Al2O3 films were 5.6 and 7.4 eV, respectively, and that the γ-Ga2O3/Al2O3 heterojunction had type-I band alignment with conduction- and valence-band-offsets of 1.6 and 0.2 eV, respectively. These findings regarding the end members of γ-(AlxGa1-x)2O3 will be beneficial for further study on γ-(AlxGa1-x)2O3-based heterostructures.