Recombination dynamics of a 268 nm emission peak in Al_(0.53)In_(0.11)Ga_(0.36)N/Al_(0.58)In_(0.02)Ga_(0.40)N multiple quantum wells

摘要

Recombination dynamics of the 268 nm photoluminescence (PL) peak in a quaternary Al_(0.53)In_(0.11)Ga_(0.36)N/Al_(0.58)In_(0.02)Ga_(0.40)N multiple quantum well (MQW) grown on relaxed AlGaN templates were studied. Although the polarization field in the compressively strained Al_(0.53)In_(0.11)Ga_(0.36)N wells was as high as 1.6 MV/cm, the value of integrated PL intensity at 300 K divided by that at 8 K (η_(int)) was as high as 1.2%. The value was similar to that obtained for the 285 nm PL peak in an Al_(0.30)Ga_(0.70)N/Al_(0.70)Ga_(0.30)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 η_(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 η_(int) to realize deep UV optoelectronic devices.