Directional light extraction enhancement from GaN-based film-transferred photonic crystal light-emitting diodes

Abstract

Articles you may be interested inHighly-directional emission patterns based on near single guided mode extraction from GaN-based ultrathin microcavity light-emitting diodes with photonic crystals Appl. Phys. Lett. 97, 013108 (2010); 10.1063/1.3459970 Enhancement of light extraction from GaN-based green light-emitting diodes using selective area photonic crystal Appl. Phys. Lett. 96, 251103 (2010); 10.1063/1.3454240 Measurement of extraction and absorption parameters in GaN-based photonic-crystal light-emitting diodes

Structural Effects on Highly Directional Far-Field Emission Patterns of GaN-Based Micro-Cavity Light-Emitting Diodes With Photonic Crystals

“…The extracted guided mode numbers were significantly affected via the GaN cavity thickness of GaN PhC MCLED. Furthermore, the guided mode dispersion of the thick GaN PhC MCLED is still quite close to the free-photons band structure because the PhC diffraction grating only has a perturbative effect on dispersion (the same as previous literatures, these photon bands diagram are not shown) [6], [17]. Nonetheless, GaN PhC uMCLED with extracts approximately two lower-order guided modes whose dispersion is more strongly affected by PhC hole depth.…”

“…2 shows the GaN MCLED structure incorporated with square PhC lattice. According to the previous work as in [6], three different PhC lattice constant values are 270, 370, and 420 nm and the hole diameter are fixed to the ratio for collimated far-field patterns, their scanning electron microscopy (SEM) images shown in Fig. 2(a)-(c).…”

Measurement of extraction and absorption parameters in GaN-based photonic-crystal light-emitting diodes

“…3,5,6 In contrast, a growing body of work has revealed the efficacy of 2D PhC patterning of GaN-based light-emitting diodes ͑LEDs͒ to achieve greater light extraction, and to control the directionality of the emitted light. [7][8][9][10][11] In these cases, the 2D PhC operates mostly outside the PBG spectral range, acting as a diffraction grating placed directly on the light source. High light extraction efficiency requires a structure design that optimizes the interaction of the guided modes with the PhCs through an appropriate selection of the LED and PhC parameters ͑thickness of layers, depth of the PhCs, position of the quantum wells ͑QWs͒, PhC period, and fill factor͒, which will translate into shorter characteristic extraction length of the guided modes compared with any dissipation length, such as absorption in the QWs and doped layers and, depending on the precise LED structure, dissipation losses from contacting materials.…”

High extraction efficiency light-emitting diodes based on embedded air-gap photonic-crystals

“…Several groups [1][2][3][4][5] demonstrated the efficacy of PhCs in controlling the direction of light emission and enhancing the extraction efficiency of LEDs. A number of different schemes are commonly applied to increase the extraction efficiency in LEDs.…”