Dome-shaped patterned sapphire substrate with optimized curvature to enhance the efficacy of light emitting diodes

Wang, Haiyan; Zhou, Shunhua; Lin, Zhien; Qiao, Tian; Liu, Zhong; Wang, Kaicheng; Hong, Xiaosong; Li, Guoqiang

doi:10.1039/c4ra04053h

Cited by 9 publications

(6 citation statements)

References 28 publications

(16 reference statements)

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“…Li et al proposed a PSS design method based on the optical analysis software TracePro [97]. This innovative approach enables one to systematically and comprehensively study the influence of all pattern parameters on the light path, and to design new patterns for PSS [98,99]. The simulation includes the following steps, i.e.…”

Section: Simulation-based Design Of Pssmentioning

confidence: 99%

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GaN-based light-emitting diodes on various substrates: a critical review

et al. 2016

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GaN and related III-nitrides have attracted considerable attention as promising materials for application in optoelectronic devices, in particular, light-emitting diodes (LEDs). At present, sapphire is still the most popular commercial substrate for epitaxial growth of GaN-based LEDs. However, due to its relatively large lattice mismatch with GaN and low thermal conductivity, sapphire is not the most ideal substrate for GaN-based LEDs. Therefore, in order to obtain high-performance and high-power LEDs with relatively low cost, unconventional substrates, which are of low lattice mismatch with GaN, high thermal conductivity and low cost, have been tried as substitutes for sapphire. As a matter of fact, it is not easy to obtain high-quality III-nitride films on those substrates for various reasons. However, by developing a variety of techniques, distincts progress has been made during the past decade, with high-performance LEDs being successfully achieved on these unconventional substrates. This review focuses on state-of-the-art high-performance GaN-based LED materials and devices on unconventional substrates. The issues involved in the growth of GaN-based LED structures on each type of unconventional substrate are outlined, and the fundamental physics behind these issues is detailed. The corresponding solutions for III-nitride growth, defect control, and chip processing for each type of unconventional substrate are discussed in depth, together with a brief introduction to some newly developed techniques in order to realize LED structures on unconventional substrates. This is very useful for understanding the progress in this field of physics. In this review, we also speculate on the prospects for LEDs on unconventional substrates.

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Section: Simulation-based Design Of Pssmentioning

confidence: 99%

“…According to the optimizations, Li et al designed different novel PSSs, e.g. dome-shaped PSS and spherical cap-shaped PSS [98,99]. Dome-shaped PSS is derived from cone-shaped PSS, by changing the generatrix of the cone-shaped pattern to a curve [99].…”

Section: Simulation-based Design Of Pssmentioning

confidence: 99%

GaN-based light-emitting diodes on various substrates: a critical review

et al. 2016

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“…In this regard, a novel type of PSS is put forward thereafter, the so-called dome-patterned PSS (DPSS). [44] 2.55 mm its total flux remains relatively high. Furthermore, EL characterizations of LED chips, shown in Fig.…”

Section: Design and Optimization Of Novel Psssmentioning

confidence: 92%

“…Through our work, various PSSs such as grooved PSS, hemisphere-patterned PSS, and cone-patterned PSS have been systematically optimized. [42][43][44] Furthermore, based on the optimization results, two novel PSSs, the so-called spherical cappatterned PSS and dome-patterned PSS, have been proposed for high-efficiency GaN-based LEDs. [43,44] Spherical cap-patterned PSS (SCPSS) is derived from hemisphere-patterned PSS (HPSS) by changing the height of its hemispherical units.…”

Section: Design and Optimization Of Novel Psssmentioning

confidence: 99%

Design of patterned sapphire substrates for GaN-based light-emitting diodes

et al. 2015

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A new method for patterned sapphire substrate (PSS) design is developed and proven to be reliable and cost-effective. As progress is made with LEDs’ luminous efficiency, the pattern units of PSS become more complicated, and the effect of complicated geometrical features is almost impossible to study systematically by experiments only. By employing our new method, the influence of pattern parameters can be systematically studied, and various novel patterns are designed and optimized within a reasonable time span, with great improvement in LEDs’ light extraction efficiency (LEE). Clearly, PSS pattern design with such a method deserves particular attention. We foresee that GaN-based LEDs on these newly designed PSSs will achieve more progress in the coming years.

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“…9 As AlGaInP has a very large refractive index (~3.5 at 630 nm), merely ~2.3% of total electroluminescent photons can escape from the surface of a planar AlGaInP LED. 6,7 Recently, a variety of techniques have been developed to improve the LEE of LEDs, including surface roughening, [10][11][12] surface patterning by using optical, e-beam or ion-beam lithography, 13 patterned substrate 14 and plasmonic nanostructures. 15,16 The essential design principle is to create additional optical channels for photons to escape from LED surface.…”

Section: Introductionmentioning

confidence: 99%

Periodic indentation patterns fabricated on AlGaInP light emitting diodes and their effects on light extraction

et al. 2014

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ARTICLE This journal isWe report a novel method for fabricating periodic indentation patterns on AlGaInP light emitting diodes (LEDs) that can effectively improve the light extraction efficiency. The patterns consist of hemispherical pits created by direct imprinting the top GaP window layer of AlGaInP LEDs with patterned sapphire (PS). The angle resolved electroluminescent tests reveal that the patterned chips show an average light emission enhancement of 155% over the original planar chips.

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Dome-shaped patterned sapphire substrate with optimized curvature to enhance the efficacy of light emitting diodes

Cited by 9 publications

References 28 publications

GaN-based light-emitting diodes on various substrates: a critical review

GaN-based light-emitting diodes on various substrates: a critical review

Design of patterned sapphire substrates for GaN-based light-emitting diodes

Periodic indentation patterns fabricated on AlGaInP light emitting diodes and their effects on light extraction

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