Luminescence properties of Er,O-codoped GaP grown by organometallic vapor phase epitaxy

We have grown Er,O-codoped GaP by organometallic vapor phase epitaxy (OMVPE) and investigated the growth conditions dependence of photoluminescence (PL) spectra due to intra-4f shell transitions of Er ions. The codoping of Er and O is performed by using an O-containing Er source, Er(DPM)3, either with or without an additional O2 flow. Several new emission lines appear by the addition of O2 into the growth ambient. Some of them are quite similar to emission lines due to an Er-2O center in Er,O-codoped GaAs. This suggests that a similar atom configuration with two O atoms is successfully formed around Er ions in GaP. The dependence of the Er-2O emission lines on growth temperature indicates the existence of a threshold growth temperature, above, which other emission lines appear. The temperature dependence of the intensity of the Er-2O emission lines reveals that thermal quenching in GaP from 23 to 300 K is smaller by about two orders in magnitude than in GaAs.