Radiative recombination dynamics of carriers in InxGa1-xN epitaxial layersrevealed by temperature dependence of time-resolved photoluminescence spectra

The radiative recombination process of InxGa1-xN epitaxial layers was inves tigated by means of the temperature dependence of time-resolved photolumine scence spectra. Two emission components separated by about 40 meV were clea rly observed. At 6 K, the higher- and lower-energy components had decay-tim e constants of 30 and 540 ps, respectively. The energy transfer of carriers between the two levels was observed. With increasing temperature, the deca y-time constant of the higher-energy component was almost constant of about 30 ps, whilst that of the lower-energy component decreased from 540 to 20 ps. On the basis of a strong electron-phonon interaction the contribution o f a polaron state of electrons to the recombination process of the higher-e nergy component is proposed.