Observation of weak carrier localization in green emitting InGaN/GaN multi-quantum well structure

Green emitting InGaN/GaN multi-quantum well samples were investigated using photoluminescence (PL) and time-resolved photoluminescence (TRPL) spectroscopy. Weak carrier localization with characteristic energy of \textasciitilde 12 meV due to an inhomogeneous distribution of In in the InGaN quantum well (QW) layer is observed. The temperature dependence of the PL peak energy exhibits S-shape phenomenon and is comparatively discussed within the framework of the Varshni's empirical formula. The full width at half maximum (FWHM) of the PL emission band shows an increasing-decreasing-increasing behavior with increasing temperature arising from the localized states caused by potential fluctuations. The radiative life time, $\tau_{\mathrm{r}}$, extracted from the TRPL profile shows \textasciitilde $T^{\mathrm{3/2}}$ dependence on temperature above 200 K, which confirms the absence of the effect of carrier localization at room temperature.