Approaching fermi level unpinning in Oxide-In0.2Ga0.8As

Electrical characteristics of oxide-In<sub>0.2</sub>Ga<sub>0.8</sub>As interface in ultra-high vacuum (UHV)-deposited Al<sub>2</sub>O<sub>3</sub>(3 nm)/Ga<sub>2</sub>O<sub>3</sub> (Gd<sub>2</sub>O<sub>3</sub>) (8.5 nm) on n- and p-In<sub>0.2</sub>Ga<sub>0.8</sub>As/GaAs are studied. Capacitance-voltage (<i>C-V</i>) measurements under light illumination and under wide range of temperatures as well as corresponding conductance-voltage (<i>G-V</i>) measurements were carried out. Extremely high-quality interfaces with free-moving Fermi-level near the conductance and valence band-edges (regions close to E<sub>c</sub> and E<sub>v</sub>) are revealed for the Ga<sub>2</sub>O<sub>3</sub>(Gd<sub>2</sub>O<sub>3</sub>)/In<sub>0.2</sub>Ga<sub>0.8</sub>As system.