Room temperature electroluminescence peaks at 1.80 and at 1.37 eV in GaP diodes doped with Zn and O are shown to be related. Emission can be shifted from one peak to the other by heat treatments. It is proposed that those emission peaks correspond to recombination at nearest neighbor ZnSingle Bond signO pairs and pairs at larger separations, respectively. The thermal activation energy associated with the transformation of red emission centers to infrared emission centers is 0.54 ± 0.15 eV. © 1968 The American Institute of Physics.