Determination of the absolute internal quantum efficiency of photoluminescence in GaN co-doped with Si and Zn

The optical properties of high-quality GaN co-doped with silicon and zinc are investigated by using temperature-dependent continuous-wave and time-resolved photoluminescence measurements. The blue luminescence band is related to the Zn-Ga acceptor in GaN:Si, Zn, which exhibits an exceptionally high absolute internal quantum efficiency (IQE). An IQE above 90% was calculated for several samples having different concentrations of Zn. Accurate and reliable values of the IQE were obtained by using several approaches based on rate equations. The concentrations of the Zn-Ga acceptors and free electrons were also estimated from the photoluminescence measurements. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3699312]