Quantitative study on the mechanisms underlying the phonon bottleneck effect in InN/InGaN multiple quantum wells

Herein, we quantitatively investigated the mechanisms of interfacial phonon mismatch and quantum confinement underlying the phonon bottleneck effect in InN/InxGa(1-x)N multiple quantum wells. Obvious extension of carrier thermalization with the longest relaxation time of 4.75 ns due to an enhanced phonon bottleneck effect was observed. It was found that a stronger quantum confinement could effectively reduce carrier relaxation rate via improving the elastic carrier-carrier scattering, while a larger phonon mismatch may give a higher initial carrier temperature due to the reflection of optical phonons and probably confinement of quasi-optical phonons. This study provides an essential theoretical insight into photovoltaic and other optoelectronic devices aiming to reduce the carrier relaxation rate via the phonon bottleneck effect.