Photoluminescence intensity change of GaP1−xNx alloys by laser irradiation

We report the influence of laser irradiation on photoluminescence (PL) intensity to study the evolution of nonradiative recombination centers in GaP1−xNx alloys. PL mapping measurements confirmed that defects to act as nonradiative recombination centers are permanently generated by laser irradiation, which results in irreversible degradation of the PL intensity. Real-time PL measurements revealed that stronger laser irradiation leads to a larger and faster decrease in the PL intensity with irradiation time. The decay of the PL intensity by laser irradiation is larger and faster for a lower nitrogen concentration, indicating that samples with a lower nitrogen concentration are abound with hidden defects to act as nonradiative recombination centers by laser irradiation. It was demonstrated that PL measurement using high-power density photoexcitation is useful to evaluate the generation or multiplication of irradiation-induced nonradiative defects, which causes the deterioration of optoelectronic devices during operation.