Shockley-Read-Hall and Auger non-radiative recombination in GaN based LEDs: A size effect study

• Published in: Applied physics letters Vol. 111; no. 2
• Main Authors: Olivier, Francois, Daami, Anis, Licitra, Christophe, Templier, Francois
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 10.07.2017
• Subjects: Applied physics; Augers; Coefficients; Display devices; Engineering Sciences; Gallium nitrides; Light emitting diodes; Photoluminescence; Radiative recombination; Size effects
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4993741

GaN-based micro light-emitting diode (μLED) arrays are very promising devices for display applications. In these arrays, each μLED works as a single pixel of a whole image. The electro-optical performance of these μLEDs is an important subject to study. Here, we investigate the influence of LED size on the radiative and non-radiative recombination. The standard ABC model has been widely used to describe the efficiency of GaN based LEDs. Using this model, we extract A, B, and C coefficients for various LED sizes, showing how the competition between radiative and non-radiative recombination processes varies with the LED geometry. Time-resolved photoluminescence allows us to determine coefficient B, related to radiative recombination. Through current-voltage-luminance characterizations, we determine parameters A and C related to Shockley-Read-Hall and Auger recombination. We find that coefficient A is strongly dependent on LED size, indicating a drastic effect of sidewall defects on the performance of LEDs. On the other hand, coefficient C is independent of LED size. This latter result demonstrates that efficiency droop does not depend on LED size.