2-D Finite-Element Modeling of ZnO Schottky Diodes With Large Ideality Factors

In this paper, we complement our previous work on the study of low-temperature rectifying junctions based on Ag/ZnO Schottky barriers. Diodes characterized by very high
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_ON
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_OFF
ratio and ideality factors considerably higher than unity, in disagreement with the thermionic emission model, are modeled with a 2-D finite-element simulator. We could discard tunneling and inhomogeneous barrier-height distribution as sources for this anomalous value. A new interface charge layer model was therefore introduced, which is able to reproduce the electrical behavior in devices with large ideality factors without decreasing the rectifying properties.