Yellow Band (YB) PL intensity falls with increasing Si doping concentration

A model of fermi-level pinning at this defect band explains the effect of doping on PL

Vertically oriented defects such as those common in GaN are likely to be responsible for YB PL

Change in GaN quality with doping indicates doping effects on growth kinetics and defects in GaN

This data available at http://www.iiiv.cornell.edu/www/schaff/gan/