Effect of surface plasmon polariton mode on spontaneous emission in gold coated GaN/InGaN quantum-well structures

Abstract

We have studied the optical properties of Au-coated InGaN/GaN quantum wells (QWs) to investigate the interaction between the surface plasmon (SP) polariton mode and the InGaN QW emission by means of SP resonance, photoluminescence (PL), and time-resolved PL techniques. A clear dispersion curve of the SP mode was found from the Au-coated layer by using angle- and wavelength-resolved SP resonance experiments. We observed that the PL peaks related to GaN were unchanged regardless of whether the QW was under an Au-coated environment or not, while the PL peak related to the active InGaN QW showed a red-shifting behavior due to the Au-coated layer. From time-resolved PL, we found a slight decrease in the decay time for the emission from the Au-coated InGaN QW area compared to that for the uncoated InGaN QW area. Although the sizes of the changes in the emission wavelength and the decay time were not so large, we can found that the SP polariton mode still affected the PL spectrum in the longer wavelength region for the Au-coated InGaN QW.