Phosphor-free white light-emitting diode with laterally distributed multiple quantum wells

Park, Il‐Kyu; Kim, Ja‐Yeon; Kwon, Min‐Ki; Cho, Chu‐Young; Lim, Jae-Hong; Park, Seong-Ju

doi:10.1063/1.2890492

Cited by 60 publications

(31 citation statements)

References 16 publications

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“…The second scheme is based on exploiting several QWs, each emitting in a different wavelength, and combining the output photoluminescence spectra. Until now, white-light LEDs that simultaneously emit two or three colors, including InGaN-GaN QWs, have been reported [5]- [9]. All of the reported structures, however, suffer from low internal quantum efficiency and low intensity emission of the red wavelength, which is principally due to the lack of an efficient red emitter.…”

Section: Introductionmentioning

confidence: 99%

“…Although there is a new trend toward novel structures such as trapezoidal InGaN-GaN MQWs [30], the main focus here is for the simple laterally [5] or vertically [31] distributed MQWs. By constructing the junction in the transverse direction, the lateral injection current causes a nearly uniform carrier concentration for all emitters.…”

Section: Proposed Vertical Structurementioning

confidence: 99%

See 1 more Smart Citation

Design of a GaN White Light-Emitting Diode Through Envelope Function Analysis

Khoshnegar

Sodagar

Eftekharian

et al. 2010

IEEE J. Quantum Electron.

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Abstract-In this paper, we present an envelope function analysis technique for the design of the emission spectra of a white quantum-well light-emitting diode (QWLED). The nanometric heterostructure that we are dealing with is a multiple QW, consisting of periods of three single QWs with various well thicknesses. With the aid of 6 6 Luttinger Hamiltonian, we employ the combination of two methods, k p perturbation and the transfer matrix method, to acquire the electron and hole wave functions numerically. The envelope function approximation was considered to obtain these wave functions for a special basis set. While adjacent valence sub-bands have been determined approximately, the conduction bands are approximated as parabolic. The effect of Stokes shift has also been taken into account. The dipole moment matrix elements for interband atomic transitions are evaluated via the correlation between the electron and hole envelope functions, for both orthogonal polarizations, thus simplifying the calculation of the photoluminescence intensity. Spatial variations in the hole/electron wave functions have been examined with the introduction of piezoelectric and spontaneous polarization internal fields. We theoretically establish the possibility of a highly efficient InGaN red emitter, resulting in a uniform luminescence in red, green, and blue emissions from a white light emitting diode by adjusting the material composition, internal field, and well thickness.Index Terms-Envelope function analysis, GaN, k p method, optical intensity spectrum, white LED.

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Section: Introductionmentioning

confidence: 99%

Section: Proposed Vertical Structurementioning

confidence: 99%

Design of a GaN White Light-Emitting Diode Through Envelope Function Analysis

Khoshnegar

Sodagar

Eftekharian

et al. 2010

IEEE J. Quantum Electron.

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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: 99%

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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“…A promising development is the phosphor-free white LED by combining multiple quantum wells. These LEDs usually consist of stacked blue and green InGaN/GaN quantum wells inserted between n-GaN and p-GaN layer [15]. Usually, the spectrum resembles the LED lights with a phosphor layer, although other types can be fabricated [16].…”

Section: Indoor Light Sourcesmentioning

confidence: 99%

A Proposal for Typical Artificial Light Sources for the Characterization of Indoor Photovoltaic Applications

2014

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There are currently no international norms which define a method for characterizing photovoltaic solar cells for indoor applications. The current standard test conditions are not relevant indoors. By performing efficiency simulations based on the quantum efficiency of typical solar cells and the light spectra of typical artificial light sources, we are able to propose the first step for developing a standard by determining which light sources are relevant for indoor PV characterization and which are not or are redundant. Our simulations lead us to conclude that indoor light sources can be divided into three different categories. For the characterization of photovoltaic solar cells in indoor environments, we propose that solar cells be measured under one light source from each group.

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Phosphor-free white light-emitting diode with laterally distributed multiple quantum wells

Cited by 60 publications

References 16 publications

Design of a GaN White Light-Emitting Diode Through Envelope Function Analysis

Design of a GaN White Light-Emitting Diode Through Envelope Function Analysis

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

A Proposal for Typical Artificial Light Sources for the Characterization of Indoor Photovoltaic Applications

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