Green InGaN/GaN based LEDs: high luminance and blue shift

Anis Daami (1, 2) , François Olivier (1, 2) , Ludovic Dupré (1, 2) , Christophe Licitra (1, 2) , Franck Henry (1, 2) , François Templier (1, 2) , Stéphanie Le Calvez (1, 2)

1 CEA - Commissariat à l'énergie atomique et aux énergies alternatives
2 DACLE-LETI - Département d'Architectures, Conception et Logiciels Embarqués-LETI

We report in this paper electro-optical results on InGaN/GaN based green micro light-emitting diodes (µLEDs). Current-light-voltage measurements reveal that the external quantum efficiency (EQE) behavior versus charge injection does not follow the ABC model prediction. Light-emission homogeneity investigation, carried out by photoluminescence mapping, shows that the Quantum Confinement Starck Effect (QCSE) is less significant at the edges of µLEDs. Electroluminescence shows a subsequent color green-to-blue deviation at high carrier injection levels. The extracted spectra at different current injection levels tend to show the appearance of discrete wavelength emissions. These observations may enhance the hypothesis that higher-energy excited-levels in InGaN quantum wells may also contribute to the blue shift, solely attributed to QCSE lessening under intense electric field magnitudes. We hereby present first results dealing with green µLEDs electro-optical performances with regards to their size.

Keywords: green µLED; InGaN/GaN; blue shift; QCSE

Domains: Engineering Sciences [physics]

Anis Daami, François Olivier, Ludovic Dupré, Christophe Licitra, Franck Henry, et al.. Green InGaN/GaN based LEDs: high luminance and blue shift. Gallium Nitride Materials and Devices XIV, SPIE, Feb 2019, San Francisco, United States. pp.21, ⟨10.1117/12.2509396⟩. ⟨cea-02941414v2⟩