Low-efficiency-droop c -plane InGaN/GaN light-emitting diodes through the use of thick single quantum wells and doped barriers

Journal Article · Fri Apr 14 00:00:00 EDT 2023 · Journal of Applied Physics

DOI:https://doi.org/10.1063/5.0142035· OSTI ID:1968941

Chow, Y. C.  ^[1]; Lynsky, C.  ^[1]; Nakamura, S.  ^[2]; DenBaars, S. P.  ^[2]; Weisbuch, C.  ^[3]; Speck, J. S.  ^[1]

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1. Materials Department, University of California, Santa Barbara, California 93106, USA
2. Materials Department, University of California, Santa Barbara, California 93106, USA, Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106, USA
3. Materials Department, University of California, Santa Barbara, California 93106, USA, Laboratoire de Physique de la Matière Condensée, École Polytechnique, CNRS, Institut Polytechnique de Paris, 91120 Palaiseau, France

Efficiency droop at high current densities is a problem for InGaN-based light-emitting diodes (LEDs), especially for conventional c-plane devices. The large internal electric fields in c-plane quantum wells (QWs) lead to an increase in the active region carrier density ( n), causing the electrical efficiency droop onset to occur at low current densities. Here, we present an approach to reduce the internal electric fields ( E _int ) in c-plane QWs by placing doped p-type and n-type GaN barriers close to the QW. The reduced E _int also allows a thick QW active region design, which helps to lower n to further reduce the droop. The concept of using doped barriers to control E _int is explained using theory and device simulations. Following that, multiple series of thick single QW (SQW) LEDs were grown and characterized. Key parameters in the epitaxial design such as the doping levels and the relative position of the doped barriers were systematically studied and optimized. By using optimized doped barriers and a thick SQW, c-plane LEDs with a low-efficiency droop of 14% at 300 A/cm ² [with respect to the peak external quantum efficiency (EQE)] and a high peak EQE of 49% were demonstrated.

• Sponsoring Organization: USDOE
• Grant/Contract Number: EE0008204; EE0009691; 2150283
• OSTI ID: 1968941
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Vol. 133 Journal Issue: 14; ISSN 0021-8979
• Publisher: American Institute of Physics
• Country of Publication: United States
• Language: English