Ageing of InGaN-based LEDs: Effects on internal quantum efficiency and role of defects. Issue 9 (August 2015)

• Record Type: Journal Article
• Authors: La Grassa, M.; Meneghini, M.; De Santi, C.; Mandurrino, M.; Goano, M.; Bertazzi, F.; Zeisel, R.; Galler, B.; Meneghesso, G.; Zanoni, E.
• Is Part Of: Microelectronics and reliability. Volume 55:Issue 9/10(2015)
• Page Start: 1775
• Page End: 1778
• Publication Date: 2015-08
• Subjects: Ageing -- InGaN -- LED -- Light-emitting-diode -- Efficiency -- Defects; Electronic apparatus and appliances -- Reliability -- Periodicals; Miniature electronic equipment -- Periodicals; Appareils électroniques -- Fiabilité -- Périodiques; Équipement électronique miniaturisé -- Périodiques; Electronic apparatus and appliances -- Reliability; Miniature electronic equipment; Periodicals; 621.3815
• DOI: 10.1016/j.microrel.2015.06.103
• Languages: English
• ISSNs: 0026-2714

Abstract

Abstract: This paper describes the degradation of InGaN-based LEDs submitted to constant current stress; based on combined electroluminescence, photoluminescence and deep-level transient spectroscopy we show that: (i) when submitted to constant current stress, LEDs can show a measurable decrease in the optical power, which is more prominent in the low current regime; (ii) the decrease in optical power is strongly correlated to the increase in the Shockley–Read–Hall recombination coefficient A, as estimated by differential lifetime measurements; (iii) stress induces the increase in the concentration of a trap level, with activation energy between 0.6 and 0.7 eV, which is supposed to be located next to/within the active region. The results suggest that the optical degradation can be ascribed to the increase in non-radiative recombination, rather than to a decrease in carrier injection efficiency. Highlights: We performed constant-current stress on InGaN-based LEDs. The decrease in optical power is correlated with the SRH coefficient. Stress induced the increase in the concentration of a trap level. Optical degradation can be ascribed to the increased non-radiative recombination.