Numerical calculation of optical phonon decay rate in InN/GaN MQW

Anharmonic decay of high frequency phonons into low frequency vibrations is a significant energy loss mechanism in semiconductors. In the field of Hot Carrier Solar Cells (HCSC), preventing this decay is of great importance as it helps increase hot carriers lifetime. Phonon decay in nitride compounds as well as their consisting nano-crystals like quantum dots and multiple quantum wells (MQWs) has not been extensively studied in the literature. In this work, the decay channels of the A1 and the high-lying E2 optical phonons in an InN/GaN MQW are analysed. We find that the no Klemens decay is present in A1 mode whereas on the contrary E2 is dominated by this process. We also observe that the linewidth for A1 is enlarged a few times than the bulk counterpart while that for E2 remains similar, which is attributed to different vibration nature.