The Investigation of Carrier Leakage Mechanism Based on ABC-Models in InGaN/GaN MQW and Its Effect on Internal Quantum Efficiency under Optical Excitation

Abstract

In this work, a GaN-based multiple quantum well (MQW) sample has a much higher IQE although it has a stronger non-radiative recombination. Through experimental verification, the higher IQE is attributed to the suppressed carrier leakage mechanism, which is normally neglected under optical excitation. To achieve a more reasonable IQE expression in a GaN MQW structure, leakage factor m is introduced into the ABC-models. Meanwhile, by analyzing the Arrhenius fitting of the plot of IQE-temperature and leakage factor m, the key temperature and excitation power turning on the carrier leakage mechanism was roughly determined to be below 220 K and 10 mW, respectively. Such a low turn-on temperature and excitation power indicates a much easier carrier leakage mechanism in GaN-based MQW, which may be caused by the small effective electron mass of InGaN (0.11–0.22 m*) and the narrow thickness of quantum well via the model calculation of energy band structure via simulation software LASTIP. Moreover, higher IQE can be achieved by suppressing the carrier leakage mechanism via structural optimization (such as electron block layer) in GaN-based MQW.

Disentangling the Impact of Point Defect Density and Carrier Localization-Enhanced Auger Recombination on Efficiency Droop in (In,Ga)N/GaN Quantum Wells

“…Moreover, room-temperature IQEs similar to the peak IQEs described here have been reported previously for high-quality green-emitting QWs: when determined by resonantly excited differential carrier lifetime measurements, IQEs ranging from 85 to 70% were observed as the indium content was increased from 10 to 28%. , As reported previously, the peak IQE for our samples obtained via the above band gap excitation was 40–50%, which is similar to the EQE values of 40–50% typically reported for green-emitting LED structures . In both cases, additional factors such as carrier injection efficiency, an uneven carrier distribution between QWs, and current leakage may further reduce device efficiency.…”

“…6,25 As reported previously, the peak IQE for our samples obtained via the above band gap excitation was 40−50%, 17 which is similar to the EQE values of 40−50% typically reported for green-emitting LED structures. 26 In both cases, additional factors such as carrier injection efficiency, an uneven carrier distribution between QWs, and current leakage 27 may further reduce device efficiency.…”