Phonon emission by photoexcited carriers in InGaN/GaN multiple quantum wells

Abstract

The effect of well width on both the photoluminescence (PL) and phonon emission in optically excited InGaN multiple quantum well (MQW) samples has been investigated. For narrow MQW samples (w < 2.5 nm), the low-temperature PL quantum efficiency is close to unity with the phonon emission being due mainly to carrier relaxation in the QWs. For wider MQWs samples the PL quantum efficiency is reduced and the intensity of the phonon emission increases. We explain this in terms of the non-radiative recombination processes in the QWs which result in phonon emission and compete with the radiative process.