Investigation of Efficiency and Droop Behavior Comparison for InGaN/GaN Super Wide-Well Light Emitting Diodes Grown on Different Substrates

• Main Authors: Tongbo Wei, Lian Zhang, Xiaoli Ji, Junxi Wang, Ziqiang Huo, Baojun Sun, Qiang Hu, Xuecheng Wei, Ruifei Duan, Lixia Zhao, Yiping Zeng, Jinmin Li
• Format: Article
• Language: English
• Published: IEEE 2014-01-01
• Series: IEEE Photonics Journal
• Subjects: Light-emitting diodes; Optical devices
• Online Access: https://ieeexplore.ieee.org/document/6939631/

In this work, efficiency droop of InGaN/GaN multiple-quantum-well LEDs with super wide well (WW) is discussed by comparing the external quantum efficiency (EQE) of GaN grown on sapphire and FS-GaN substrates. The luminescence and electrical characteristics of these WW LEDs are also experimentally and theoretically analyzed. With the increase of well width from 3 nm to 6 nm, high V-pits density and more strain relaxation are found in WW LED on sapphire, which exhibits greatly reduced peak efficiency but almost negligible droop behavior. In contrast, despite a larger polarization field, WW LED on FS-GaN shows obviously enhanced peak efficiency and comparable droop compared to the counterpart with 3-nm well. The Auger recombination probably dominates the mechanism of efficiency droop rather than defect-related nonradiative recombination or polarization effect in the WW LED on both sapphire and FS-GaN, especially at high current density.