Defect chemical modeling of Pd/ZnO Schottky junctions

We describe a comprehensive calculation procedure for modeling metal/semiconducting oxide Schottky junctions and present detailed model calculations of the electrostatic potential, defect distribution profiles, and energy band diagrams across Pd/ZnO Schottky junctions simulated for realistic processing conditions. The underlying approach involves self consistent numerical solution of Poisson's equation coupled with the defect equilibria of ZnO. According to our calculations the built-in voltage is predicted to be 0.63 or 0.57 V and the space charge region width is predicted to be 0.61 or 2.46 μm for undoped ZnO films grown at 800 or 700 °C, respectively, and subsequently annealed at 450 °C following the metallization step. Our calculation procedure can be readily extended to simulate other processing conditions and other material systems.

► We present a methodology for modeling semiconducting oxide Schottky junctions. ► Our methodology accounts for the defect structure of the semiconducting oxide layer. ► The method is applied to the Pd/ZnO Schottky junction. ► The ionic defects have important role in shaping the junction characteristics. ► Growth conditions are expected to provide handles for tailoring junction properties.