Recombination dynamics of a 268nm emission peak in Al0.53In0.11Ga0.36N∕Al0.58In0.02Ga0.40N multiple quantum wells

Recombination dynamics of the $268\mathrm{nm}$ photoluminescence (PL) peak in a quaternary ${\mathrm{Al}}_{0.53}{\mathrm{In}}_{0.11}{\mathrm{Ga}}_{0.36}\mathrm{N}∕{\mathrm{Al}}_{0.58}{\mathrm{In}}_{0.02}{\mathrm{Ga}}_{0.40}\mathrm{N}$ multiple quantum well (MQW) grown on relaxed AlGaN templates were studied. Although the polarization field in the compressively strained ${\mathrm{Al}}_{0.53}{\mathrm{In}}_{0.11}{\mathrm{Ga}}_{0.36}\mathrm{N}$ wells was as high as $1.6\mathrm{MV}∕\mathrm{cm}$ , the value of integrated PL intensity at $300\mathrm{K}$ divided by that at $8\mathrm{K}$ $\left({\eta }_{\mathrm{int}}\right)$ was as high as 1.2%. The value was similar to that obtained for the $285\mathrm{nm}$ PL peak in an ${\mathrm{Al}}_{0.30}{\mathrm{Ga}}_{0.70}\mathrm{N}∕{\mathrm{Al}}_{0.70}{\mathrm{Ga}}_{0.30}\mathrm{N}$ MQW (1.3%), though the AlN molar fraction in the wells was higher by a factor of 1.7. According to these results and the fact that time-resolved PL signal exhibited a stretched exponential decay shape, the improved ${\eta }_{\mathrm{int}}$ of the AlInGaN wells was attributed to a beneficial effect of the exciton localization as is the case with InGaN alloys; doping or alloying with InN was confirmed to work also on AlGaN in improving ${\eta }_{\mathrm{int}}$ to realize deep UV optoelectronic devices.