Oxidized noble metal Schottky contacts to n-type ZnO

Deliberately oxidized iridium, platinum, and palladium Schottky contacts were fabricated on the Zn-polar and O-polar faces of hydrothermal bulk ZnO by eclipse pulsed laser deposition in an oxygen ambient. The barrier heights of these oxidized contacts were significantly higher than their plain metal counterparts, with ideality factors approaching the image-force-controlled limit for laterally homogeneous interfaces. The key aspects of this technique are a low deposition energy and the use of an oxidizing environment which reduces interfacial defects, particularly oxygen vacancies. In each case, the barriers on the Zn-polar face were 210–260 meV higher than those on the O-polar face.