Exciton dynamics in nonpolar (112̄0) InGaN/GaN multiple quantum wells grown on GaN templates prepared by lateral epitaxial overgrowth

Exciton dynamics in nonpolar (11-20) In_xGa_1-xN/GaN multiple quantum wells (QWs) grown on GaN templates prepared by lateral epitaxial overgrowth were studied. Due to the absence of the polarization fields normal to the QW plane, the photoluminescence (PL) peak energy moderately shifted to the higher energy and the radiative lifetime did not change remarkably with the decrease in the well thickness. Similar to the case for polar InGaN QWs, time-resolved PL signals exhibited the nonexponential decay shape, which can be explained by thermalization and subsequent localization of excitons. Although the growth conditions were not fully optimized, values of the PL intensity at 300 K divided by that at 8 K were 25 and 17% for the peaks at 2.92 and 2.60 eV, respectively.