Barrier inhomogeneity in Ag Schottky contacts to bulk ZnO grown by different methods

Abstract

The electrical properties of Ag Schottky contacts to differently grown bulk ZnO single crystals were comparatively investigated. Schottky contacts to O-polar ZnO revealed higher barrier heights and lower ideality factors than those to Zn-polar ZnO. A higher degree of oxidation at the Ag-ZnO interface might occur for the O-polar ZnO, increasing the barrier heights. Compared to the current values measured under vacuum, those measured in an air ambient were decreased, suggesting that compensation of the surface conductive layer by acceptor-like adsorbates such as O 2 and H 2O plays an important role in the current transport of Ag/ZnO contacts. © 2012 The Korean Physical Society.