Cascade single-chip phosphor-free white light-emitting diodes

Guo, Xia; Guang-di, Shen; Guan, Baolu; Gu, Xin‐Yan; Wu, Di; Li, Y. B.

doi:10.1063/1.2830991

Cited by 37 publications

(26 citation statements)

References 9 publications

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“…It was reported that after laser lifting the sapphire substrate of a blue LED, a green LED was bonded with the blue LED [15]. Also, X. Guo et al developed a method by wafer bonding an InGaN-based blue LED with an AlGaInP-based red LED to form the white-light device with blue and red emissions [16], which presented perfect CIE chromaticity coordinates near to (0.3, 0.3) at the injection current of 20 mA.…”

Section: Review Of Phosphor-free Monolithic White Light Ledsmentioning

confidence: 98%

“…For stripe patterns, as reported by K. Hiramatsu et al, the SAE of GaN with stripe patterns oriented along different directions are inclined and bound by different semipolar planes. When the GaN was selectively grown on the SiO 2 stripes along the [11][12][13][14][15][16][17][18][19][20] direction for different growth temperatures and reactor pressures, {1-101} surfaces without or with narrow (0001) appeared, the growth rate of {1-101} was almost constant and independent of the growth conditions. As for the SAE GaN on the stripes along direction, Fig.…”

Section: Growth Of Gan Microfacets Using Selective Area Epitaxy and Rmentioning

confidence: 99%

“…In order to explain the mechanisms of SAE GaN grown along [11][12][13][14][15][16][17][18][19][20] and directions, Fig. 7 shows the schematic modes of the morphological change and corresponding atomic configurations.…”

Section: Growth Of Gan Microfacets Using Selective Area Epitaxy and Rmentioning

confidence: 99%

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InGaN/GaN multiple quantum wells on selectively grown GaN microfacets and the applications for phosphor-free white light-emitting diodes

et al. 2016

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Phosphor-free InGaN/GaN multiple quantum well (MQW) white light-emitting diodes (LEDs) have the advantages of simpler device process and potentially higher efficiency, and have attracted much attention in recent years. A host of technologies are emerging for implementing such white-light LEDs. Among them, the key issue is the color tuning of different emission wavelengths from InGaN/GaN MQWs with different indium (In) content. However, owing to the limited growth technology for long-wavelength InGaN/GaN MQWs with high In content, it is very attractive to study selective area epitaxy (SAE) of InGaN/GaN MQWs on GaN microstructures with non-or semipolar microfacets combined with (0001) c-plane. In this paper, we briefly review the previous developments of InGaN/GaN MQW based phosphor-free white light LEDs, then the particular technology for the growth of InGaN/GaN MQWs on the regrown GaN microfacets using SAE has been introduced, and related mechanisms for the formation of different non-or semipolar GaN microfacets fabricated by various mask patterns are discussed in detail. Furthermore, sophisticated approaches made use of the InGaN/GaN MQWs on GaN microfacets to fabricated phosphor-free white light LEDs with polychromatic emissions are reviewed.

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Section: Review Of Phosphor-free Monolithic White Light Ledsmentioning

confidence: 98%

Section: Growth Of Gan Microfacets Using Selective Area Epitaxy and Rmentioning

confidence: 99%

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InGaN/GaN multiple quantum wells on selectively grown GaN microfacets and the applications for phosphor-free white light-emitting diodes

et al. 2016

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“…Many approaches have been proposed to fabricate single-chip white LEDs without using phosphors for the phosphors covered LEDs suffer from lower efficiency and the multi-chip LEDs have the disadvantages of assembling complication [1][2][3]. A prospective approach for obtaining phosphor-free single-chip white LEDs is using GaN-based irregular multiple quantum well (IMQW) structures, which have been reported in our previous works [4,5].…”

Section: Introductionmentioning

confidence: 98%

Barrier effects on the optoelectronic properties of GaN-based irregular multiple quantum wells for dichromatic white LEDs

Chen

2010

Sci. China Technol. Sci.

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The GaN-based irregular multiple quantum well (IMQW) structures for dichromatic white light-emitting diodes (LEDs) are assembled by two different types of QWs emitting complementary blue and yellow light. The electronic and optical properties of the designed GaN-based IMQW structures are investigated in details by fully considering the effects of strain, well-coupling, valence band-mixing and polarization effect by employing a newly modified theoretical model based on the k⋅p theory. The influences of the height and thickness of the barrier between blue QWs and yellow QWs together with the polarization effect on the optoelectronic properties of GaN-based IMQW structure are analyzed. Numerical results show that the ratio of the two color lights emmited from the IMQW structure for dichromatic white LED can be tuned by changing the height and thickness of the barrier between two types of QWs. irregular multiple quantum wells, GaN-based materials, white light-emitting diodes Citation:Chen G X, Lu H M. Barrier effects on the optoelectronic properties of GaN-based irregular multiple quantum wells for dichromatic white LEDs. Sci

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“…Several techniques have since been proposed for generation of phosphor free white LEDs. Huang et al has generated white emission using pre-strained growth of InGaN/GaN quantum wells (QWs) [4] while Guo et al has used a single cascade LEDs chip consisting of InGaN and AlGaInP multiple quantum wells (MQWs) based LEDs integrated by wafer bonding [5]. This technique required additional wafer bonding step and the degradation of the two materials system may differ with usage leading to change in color quality with time.…”

mentioning

confidence: 98%

Novel tunable phosphor‐free white III‐nitride light emitting diodes based on indium rich InGaN nanostructures

Soh

Liu

Chua

et al. 2009

Phys. Status Solidi (c)

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Phosphor free tunable white light emitting diodes (LEDs) have been fabricated using stacked InGaN/GaN quantum wells (QWs) comprised of a lower set of red emitting QWs with an upper set of blue and green emitting QW layers. With antisurfactant treatment, indium rich InGaN nanostructures are incorporated in the InGaN/GaN quantum well during growth. AFM study shows the formation of InGaN nanostructures with an average diameter of 40‐80 nm in the quantum well layer. This growth technique enables red emitting III‐Nitride based LEDs to be generated. With the growth of additional stacked blue/green QWs on these red emitting QWs with InGaN nanostructure incorporation for white light generation, competition arises between the quantum well layers for thermalization of injected carriers. The transport of holes from the p‐GaN layer determines the radiative recombination event as holes have a lower mobility than electrons. At low injection current, emission from the upper blue/green QWs layer dominates where electron–hole (e–h) pair recombination takes place. With higher injection current, more holes diffuse across the GaN barrier to recombine with electrons at the InGaN nanostructures in the lower sets of QWs. Based on the band structure for the stacked QWs, the existence of these In‐rich nanostructures leads to more effective carrier trapping at the lower set of QWs as electrons have to overcome an additional potential barrier (at the interface of InGaN nanostructures to the InGaN well layer). There is also a higher tendency for thermalization of carriers at the lower energy states. The effect of band filling under higher injection current also enables the excess holes to recombine at the lower set of QW layers with indium rich nanostructure, which accounts for the continuous increase in higher emission wavelength from the EL spectra. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Cascade single-chip phosphor-free white light-emitting diodes

Cited by 37 publications

References 9 publications

InGaN/GaN multiple quantum wells on selectively grown GaN microfacets and the applications for phosphor-free white light-emitting diodes

InGaN/GaN multiple quantum wells on selectively grown GaN microfacets and the applications for phosphor-free white light-emitting diodes

Barrier effects on the optoelectronic properties of GaN-based irregular multiple quantum wells for dichromatic white LEDs

Novel tunable phosphor‐free white III‐nitride light emitting diodes based on indium rich InGaN nanostructures

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