Defect quasi Fermi level control-based CN reduction in GaN: Evidence for the role of minority carriers
Abstract
Compensating point defect reduction in wide bandgap semiconductors is possible by above bandgap illumination based defect quasi Fermi level (dQFL) control. The point defect control technique employs excess minority carriers that influence the dQFL of the compensator, increase the corresponding defect formation energy, and consequently are responsible for point defect reduction. Previous studies on various defects in GaN and AlGaN have shown good agreement with the theoretical model, but no direct evidence for the role of minority carriers was provided. In this work, we provide direct evidence for the role of minority carriers in reducing point defects by studying the predicted increase in work done against defect (CN−1) formation with the decrease in the Fermi level (free carrier concentration) in Si doped GaN at a constant illumination intensity. Comparative defect photoluminescence measurements on illuminated and dark regions of GaN show an excellent quantitative agreement with the theory by exhibiting a greater reduction in yellow luminescence attributed to CN−1 at lower doping, thereby providing conclusive evidence for the role of the minority carriers in Fermi level control-based point defect reduction.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 09, 2017
- Source ID
- 10.1063/1.5000720
Entities
People
- Felix Kaess
- James Tweedie
- Pramod Reddy
- Ramón Collazo
- Ronny Kirste
- Seiji Mita
- Zlatko Sitar
Organizations
- Air Force Office of Scientific Research
- Army Research Office
- National Science Foundation
- North Carolina State University