Conduction and valence band offsets of LaAl2O3 with (−201) β-Ga2O3

Wide bandgap dielectrics are needed as gate insulators and surface passivation layers on the emerging electronic oxide Ga2O3. X-ray photoelectron spectroscopy was used to determine the valence band offset at LaAl2O3 (LAO)/β-Ga2O3 heterointerfaces. LaAl2O3 was deposited by RF magnetron sputtering onto bulk Ga2O3 crystals. The bandgaps of the materials were determined by reflection electron energy loss spectroscopy to be 4.6 eV for Ga2O3 and 6.4 eV for LAO. The valence band offset was determined to be −0.21 ± 0.02 eV (staggered gap, type II alignment) for LAO on Ga2O3. This leads to a conduction band offset of 2.01 ± 0.60 eV for LaAO with Ga2O3. Thus, LAO provides excellent electron confinement but not hole confinement in LAO/Ga2O3 heterostructures.

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