Green light-emitting diodes with InGaN/GaN multiple quantum well structures: Time-resolved photoluminescence, emission dynamics and related studies

To explore the mechanism, breakthrough the current bottleneck and overcome the efficiency droop from green InGaN/GaN multiple quantum wells (MQWs) light-emitting diodes (LEDs). The photoluminescence properties and carrier dynamics of green InGaN/GaN MQW LEDs are investigated by temperature-dependent photoluminescence (PL) from 10 K to 300 K and time-resolved PL (TRPL) measurements at 10 K in our new-built lab. With increasing temperature, a blue shift of PL behavior is attributed to band-tail states formed in local potential minima resembling In-rich clusters. The energy-dependent TRPL experiments are measured at 10 K to study the carrier dynamics in the MQWs. The results show that the PL slow decays for the low-energy side are much slower than the high-energy side. The depth of carrier localization is obtained by fitting the reduced slow decay time with the emission energy increasing. All the results indicate that the PL peak is related to localized radiative recombination.