Improvement of External Extraction Efficiency in GaN-Based LEDs by $ \hbox{SiO}_{2}$ Nanosphere Lithography

Hsieh, Min Yann; Wang, Cheng Yin; Chen, Liang Yi; Lin, Tzu Pu; Ke, Manzhu; Cheng, Yun Wei; Yu, Yi Cheng; Chen, Cheng Pin; Yeh, Dong Ming; Lu, Chih Feng; Huang, Chi Feng; Yang, C. C.; Huang, Jian

doi:10.1109/led.2008.2000918

Cited by 50 publications

(22 citation statements)

References 11 publications

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“…The GaN nanorods were defined by various methods like conventional photolithography, e-beam lithography, and nanoimprint lithography, or other low cost methods, for example, nanoscale self-organized nickel islands as etching mask or SiO 2 nanosphere lithography. [115][116][117][118] Dry etching methods, such as RIE-ICP, were used to achieve high aspect ratio GaN nanopillars.…”

Section: Gan Nanoledmentioning

confidence: 99%

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GaN based nanorods for solid state lighting

Li¹,

Waag

2012

Journal of Applied Physics

495

394

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In recent years, GaN nanorods are emerging as a very promising novel route toward devices for nano-optoelectronics and nano-photonics. In particular, core-shell light emitting devices are thought to be a breakthrough development in solid state lighting, nanorod based LEDs have many potential advantages as compared to their 2 D thin film counterparts. In this paper, we review the recent developments of GaN nanorod growth, characterization, and related device applications based on GaN nanorods. The initial work on GaN nanorod growth focused on catalyst-assisted and catalyst-free statistical growth. The growth condition and growth mechanisms were extensively investigated and discussed. Doping of GaN nanorods, especially p-doping, was found to significantly influence the morphology of GaN nanorods. The large surface of 3 D GaN nanorods induces new optical and electrical properties, which normally can be neglected in layered structures. Recently, more controlled selective area growth of GaN nanorods was realized using patterned substrates both by metalorganic chemical vapor deposition (MOCVD) and by molecular beam epitaxy (MBE). Advanced structures, for example, photonic crystals and DBRs are meanwhile integrated in GaN nanorod structures. Based on the work of growth and characterization of GaN nanorods, GaN nanoLEDs were reported by several groups with different growth and processing methods. Core/shell nanoLED structures were also demonstrated, which could be potentially useful for future high efficient LED structures. In this paper, we will discuss recent developments in GaN nanorod technology, focusing on the potential advantages, but also discussing problems and open questions, which may impose obstacles during the future development of a GaN nanorod based LED technology.

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Section: Gan Nanoledmentioning

confidence: 99%

“…115,116,118,120 However, using a top-down method, a large portion of GaN material is etched away and does not contribute to light emission any more. This will add additional cost during device fabrication compared to the bottom-up (growth) method.…”

Section: Gan Nanoledmentioning

confidence: 99%

GaN based nanorods for solid state lighting

Li¹,

Waag

2012

Journal of Applied Physics

495

394

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Section: Light Emitting Diodesmentioning

confidence: 98%

“…They describe the use of spin-coating to texture the LEDs with a monolayer of silica nanoparticles. Their results show that textured p-GaN and indium tin oxide LEDs exhibit significant improvements as compared to conventional LEDs with disparity in electrical characteristics [137]. Kim et al reported that arrays of silica nanosphere monolayers that were spin-casted onto a polymer layer on top of a GaN surface can result in a hexagonal pattern of nanolenses that was shown to improve the light extraction efficiency of ultra violet LEDs by 23% [138].…”

Section: Light Emitting Diodesmentioning

confidence: 99%

Bottom-Up Assembly and Applications of Photonic Materials

Zheng

Ravaine

2016

Crystals

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Abstract:The assembly of colloidal building-blocks is an efficient, inexpensive and flexible approach for the fabrication of a wide variety of photonic materials with designed shapes and large areas. In this review, the various assembly routes to the fabrication of colloidal crystals and their post-assembly modifications to the production of photonic materials are first described. Then, the emerging applications of the colloidal photonic structures in various fields such as biological and chemical sensing, anti-reflection, photovoltaics, and light extraction are summarized.

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“…Surface passivation with appropriate dielectric layers is also necessary to avoid non-radiative recombination for high η rad [2]. Special techniques such as control of surface roughness [3][4][5], preparation of patterned sapphire substrate (PSS) [6,7], application of flip-chip bonding [8][9][10], adaption of laser lift-off process [11], and formation of photonic crystal structure [12] are frequently used to improve η ext , which can be increased by increasing the critical angle for the emitted light through an appropriate modification of the surface of the LED [13,14]. Anti-reflection (AR) coating of dielectric layers is frequently used to reduce the Fresnel reflection at the semicon-ductor-air interface in communication LEDs.…”

Section: Introductionmentioning

confidence: 99%

Enhancement in Light Extraction Efficiency of GaN-Based Light-Emitting Diodes Using Double Dielectric Surface Passivation

Yang¹,

Kim²,

Park³

et al. 2012

OPJ

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SiO 2 /Al 2 O 3 double dielectric stack layer was deposited on the surface of the GaN-based Light-Emitting Diode (LED). The double dielectric stack layer enhances both the electrical characteristics and the optical output power of the LED because the first Al 2 O 3 layer plays a role of effectively passivating the p-GaN surface and the second lower index SiO 2 layer increases the critical angle of the light emitted from the LED surface. In addition, the effect of the Fresnel reflection is also responsible for the enhancement in output power of the double dielectric passivated LED. The leakage current of the LED passivated with Al 2 O 3 layer was -3.46 × 10 -11 A at -5 V, at least two and three orders lower in magnitude compared to that passivated with SiO 2 layer (-7.14 × 10 -9 A) and that of non-passivated LED (-1.9 × 10 -8 A), respectively, which indicates that the Al 2 O 3 layer is very effective in passivating the exposed GaN surface after dry etch and hence reduces nonradiative recombination as well as reabsorption of the emitted light near the etched surface.

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Improvement of External Extraction Efficiency in GaN-Based LEDs by $ \hbox{SiO}_{2}$ Nanosphere Lithography

Cited by 50 publications

References 11 publications

GaN based nanorods for solid state lighting

GaN based nanorods for solid state lighting

Bottom-Up Assembly and Applications of Photonic Materials

Enhancement in Light Extraction Efficiency of GaN-Based Light-Emitting Diodes Using Double Dielectric Surface Passivation

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