Controlled band offset in ( Gd 2 O 3 ) 1 − x ( SiO 2 ) x ( 0 ⩽ x ⩽ 1 ) ∕ n - GaAs (001) structure

This letter investigates the chemistry and energy band structure of ( Gd 2 O 3 ) 1 − x ( SiO 2 ) x ( 0 ⩽ x ⩽ 1 ) films grown on n -GaAs (001). Dielectric band gap and interfacial band alignment of Gd 2 O 3 films were modified by compounding with SiO 2 . Binding energy shift of core level was observed from different electronegativity of second nearest-neighbor element. Controlled parameters of energy band structure were systematically characterized by valence band, absorption, and energy loss spectra. Assuming no Fermi level pinning in the midgap of n -GaAs, band offset values represent almost linear dependency on the concentration of SiO 2 . The correlation of band offset with the electrical properties, as probed by capacitance and leakage current measurements, was also discussed.