Luminescence Dynamics of Exciton Replicas in Homoepitaxial GaN Layers

K.P. Korona, J.M. Baranowski, K. Pakuła Institute of Experimental Physics, Warsaw University, Hoża 69, 00-681 Warszawa, Poland B. Monemar, J.P. Bergman Department of Physics and Measurement Technology, Linköping University, 581 83 Linköping, Sweden I. Grzegory and S. Porowski High Pressure Research Center, Polish Academy of Sciences, Sokołowska 29/37, 01-142 Warszawa, Poland

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Photoluminescence of excitons and their phonon replicas in homoepitaxial MOCVD-grown gallium nitride (GaN) layers have been studied by picosecond (ps) time-resolved photoluminescence spectroscopy. The time-resolved photoluminescence spectroscopy has shown that the free excitons and their replicas have the fastest dynamics (decay time of about 100 ps). Then, the excitons-bound-to-donors emission rises (with the rise time similar to the free excitons decay time) and decays with t=300 ps. The excitons-bound-to-acceptors has the slowest decay (about 500 ps). It has been found that the ratio of excitons-bound-to-acceptors and excitons-bound-to-donors amplitudes and their decay times are different for 1-LO replicas and then for zero-phonon lines, whereas the ratio of amplitudes and the decay time of the 2-LO replicas are similar to the ones of the zero-phonon lines.

DOI: 10.12693/APhysPolA.92.841 PACS numbers: 71.35.-y, 78.47.+p, 78.55.Cr