Photoluminescence and photoreflectance measurements on InGaN/GaN structures

The emission mechanisms of localized excitons in InGaN/GaN structures have been investigated by means of photoluminescence (PL), photoreflectance (PR) , and time-resolved Pi,. From the excitation dependence of full width at ha lf maximum (FWHM), it can be seen that the localization of the peak at 2.96 eV in the PL spectrum is weaker than that at 2.91 eV. The obtained PR sign als are attributed to discrete transition energies in the InGaN lever rangi ng from 2.8 to 3.3 eV. Six emission bands in the PL spectrum at 10 K are as signed to recombinations of excitons which are localized at different poten tial minima and whose transition energies are obtained from the PR spectrum . Time-resolved PL measurements are also investigated at various emission p hc,tun energies.