Epitaxial growth and band alignment of (GdxLa1−x)2O3 films on n-GaAs (0 0 1)

Herein we demonstrate the epitaxial stabilization of single-crystalline (GdxLa1−x)2O3 films on n-GaAs (0 0 1) with a controlled lattice match. (GdxLa1−x)2O3 films have an in-plane epitaxial relationship with a twofold rotation on GaAs (0 0 1). Spectroscopic characterization by photoemission and absorption confirms that the band gap of (GdxLa1−x)2O3 film is approximately ∼5.8 eV. However, the conduction band offset is increased by the unpinned Fermi level of the n-GaAs in the (GdxLa1−x)2O3 film (x = 0.97). The correlation of the crystalline property and the interfacial band offset by the electrical properties, as probed by capacitance and leakage current measurements, is also discussed.