Schottky barrier formation at the Au to rare earth doped GaN thin film interface

¹ Air Force Institute of Technology, 2950 Hobson Way, Wright Patterson Air Force Base, OH 45433, USA
² Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00931-3343, USA
³ The J. Bennett Johnston Sr. Center for Advanced Microstructures and Devices, Louisiana State University, 6890 Jefferson Highway, Baton Rouge, LA 70806, USA
⁴ Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska, P.O. Box 880111, Lincoln, NE 68588-0111, USA

^a e-mail: stephen.mchale@afit.edu
^b e-mail: john.mcclory@afit.edu

Received: 23 February 2010
Accepted: 31 March 2011
Published online: 18 August 2011

Abstract

The Schottky barriers formed at the interface between gold and various rare earth doped GaN thin films (RE = Yb, Er, Gd) were investigated in situ using synchrotron photoemission spectroscopy. The resultant Schottky barrier heights were measured as 1.68 ± 0.1 eV (Yb:GaN), 1.64 ± 0.1 eV (Er:GaN), and 1.33 ± 0.1 eV (Gd:GaN). We find compelling evidence that thin layers of gold do not wet and uniformly cover the GaN surface, even with rare earth doping of the GaN. Furthermore, the trend of the Schottky barrier heights follows the trend of the rare earth metal work function.