Energy band structure and electrical properties of (La₂ O ₃) 1-x (SiO₂) x (0≤x≤1) n-GaAs (001) system

This letter investigates the chemical bonding state and energy band structure of (La2 O3) 1-x (SiO2) x (0≤x≤1) films grown on sulfur-passivated n -GaAs (001). The dielectric bandgap and interfacial band alignment were modified by compounding the La2 O3 films with SiO2. A shift in binding energy of the core level was observed by comparing the electronegativities of the second nearest-neighbor element. The controlled parameters of energy band structure were systematically monitored by valence band and absorption spectra. Band offset values were almost linearly related to the concentration of SiO2 when no Fermi level pinning in the midgap of n -GaAs was assumed. The correlation between band parameter and electrical properties, as probed by capacitance and leakage current measurements, is discussed.