Resonant photoemission of rare earth doped GaN thin films

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, 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, Theodore Jorgensen Hall, 855 North 16th Street, University of Nebraska, P.O. Box 880299, Lincoln, NE 68588-0299, USA

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

Received: 26 May 2011
Revised: 7 June 2011
Accepted: 21 June 2011
Published online: 28 September 2011

Abstract

The 4d → 4f Fano resonances for various rare earth doped GaN thin films (RE = Gd, Er, Yb) were investigated using synchrotron photoemission spectroscopy. The resonant photoemission Fano profiles show that the major Gd and Er rare earth 4f weight is at about 5–6 eV below the valence band maximum, similar to the 4f weights in the valence band of many other rare earth doped semiconductors. For Yb, there is very little resonant enhancement of the valence band of Yb doped GaN, consistent with a largely 4f¹⁴ occupancy.