Parasitic sub-band-gap emission originating from compensating native defects in Si doped AlGaN

Abstract

The authors investigate the dependence of the photoluminescence intensity ratio between the near-band-edge and the parasitic blue emission as a function of silane flow in n-type Al0.3Ga0.7N. It is found that when the silane flow rate is higher than 1.13x10(-9) mol/min, the UV-to-blue ratio is a constant. When the silane flow rate is lower than 1.13x10(-9) mol/min, the UV-to-blue ratio increases rapidly as the silane flow rate decreases. A theoretical model is proposed, which assumes that the parasitic blue emission is caused by an acceptorlike compensating native defect. The model is fully consistent with the experimental results. (c) 2007 American Institute of Physics.