High Schottky barrier formation in tilted-dipole PdCoO2/ <b> <i>β</i> </b> -Ga2O3 (001) interfaces

Abstract

We report the growth and Schottky junction characteristics of metallic delafossite PdCoO2/β-Ga2O3 (001) heterostructures. The PdCoO2 thin films predominantly grow with the epitaxial relationship of PdCoO2 (006)//β-Ga2O3 (202), forming a high-quality oxide–oxide interface. Despite a 24° tilt between the PdCoO2 surface polarization axis and the β-Ga2O3 (001) surface normal, a large Schottky barrier height of ϕbJV &amp;gt; 1.7 eV was achieved. This value is comparable with that reported for PdCoO2/β-Ga2O3 (2¯01) where the PdCoO2 surface polarization axis is perpendicular to the interface. The PdCoO2/β-Ga2O3 (001) Schottky junctions showed a large on–off ratio of ∼108 at 573 K. These results demonstrate the feasibility of delafossite-type electrodes for β-Ga2O3 (001) heterostructures with high-quality homoepitaxial β-Ga2O3 layers.