TECHNICAL DESCRIPTION

The invention concerns an light-emitting diodes whereby the emitting medium for converting electron-hole pairs into photons is comprised between parallel mirrors. The converting means (quantum wells or the like) and the first and second mirrors are designed to simultaneously ensure the confinement between the mirrors of a guided propagation mode. To reach a good extraction efficiency of the LED, the device comprises light extracting means such as gratings, which may be lying across the mirrors and the n and p contacts.

Example of an implementation in AlGaAS/Alox, cf [2]

BENEFITS

The invention improves the yield of photon extraction for thin light-emitting diodes of the microcavity type, with top and bottom mirrors that enhance the extraction of the basic planar device. The aim of the invention is to extract the light otherwise lost in guided modes, and to increase all the photonic figures of merits of the corresponding LEDs (extraction efficiency, wall-plug efficiency, lumen/watt,…). Additionally, the possibility to implement original geometry of extracting photonic crystals such as Archimedean lattices and more “random” ones opens useful perspectives for obtaining deterministically shaped emission diagrams with good extraction, based on the specific properties of these lattices. 

INDUSTRIAL APPLICATIONS

Improvement of all kinds of LEDs that implement microcavities : GaAs or AlInGaP or other III-V based LEDs. Nitride LEDS with thin enough layers to implement a useful microcavity effect. OLEDs (Organic LEDs) could also be considered.

ADDITIONAL INFORMATION

Related publications

[1]        M. Rattier, H. Benisty, E. Schwoob, C. Weisbuch, T. F. Krauss, C. J. M. Smith, R. Houdré, and U. Oesterle, « Omnidirectional  and compact guided light extraction from Archimedean photonic lattices, » Appl. Phys. Lett., vol. 83, pp. 1283-1285, 2003.
[2]        M. Rattier, H. Benisty, R. Stanley, J.-F. Carlin, R. Houdré, U. Oesterle, C. J. M. Smith, C. Weisbuch, and T. F. Krauss, « Towards Ultra-High Efficiency Aluminum Oxide Microcavity Light-Emitting Diodes: Guided Mode Extraction by Photonic Crystals, » Journal of Selected Topics in Quantum Electronics, vol. 8, pp. 238-247, 2002.
[3]        M. Rattier, T. F. Krauss, J.-F. Carlin, R. Stanley, U. Oesterle, R. Houdré, C. J. M. Smith, R. M. D. L. Rue, H. Benisty, and C. Weisbuch, « High extraction efficiency, laterally injected, light emitting diodes combining microcavities and photonic crystals., » Optical and Quantum Electronics, vol. 34, pp. 79-89, 2002.
[4]        H. Benisty, J. Danglot, A. Talneau, S. Enoch, J. M. Pottage, and A. David, « Investigation of Extracting Photonic Crystal Lattices for Guided Modes of GaAs-Based Heterostructures, » IEEE J.  Quantum Electron., vol. 44, pp. 777-789, 2008.
[5]        A. David, T. Fujii, E. Matioli, R. Sharma, K. McGroddy, S. Nakamura, S. P. Denbaars, C. Weisbuch, and H. Benisty, « GaN light-emitting diodes with Archimedean lattice photonic crystals, » Appl. Phys. Lett., vol. 88, pp. 073510 2006.

Example of extraction diagrams for a lattice at the periphery of a round zone [1]

For further information, please contact us (Ref 84905-01)