WO2008144337A1 - Light emitting diode based on multiple double-heterostructures (quantum wells) with rare earth doped active regions - Google Patents
Light emitting diode based on multiple double-heterostructures (quantum wells) with rare earth doped active regions Download PDFInfo
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- WO2008144337A1 WO2008144337A1 PCT/US2008/063597 US2008063597W WO2008144337A1 WO 2008144337 A1 WO2008144337 A1 WO 2008144337A1 US 2008063597 W US2008063597 W US 2008063597W WO 2008144337 A1 WO2008144337 A1 WO 2008144337A1
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- Prior art keywords
- light
- quantum well
- emitting diode
- emitting
- well layers
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- 229910052761 rare earth metal Inorganic materials 0.000 title description 11
- 150000002910 rare earth metals Chemical class 0.000 title description 6
- 150000002500 ions Chemical class 0.000 claims abstract description 16
- 239000012190 activator Substances 0.000 claims abstract description 15
- 239000000956 alloy Substances 0.000 claims description 16
- 229910045601 alloy Inorganic materials 0.000 claims description 16
- 239000002019 doping agent Substances 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- 238000004020 luminiscence type Methods 0.000 description 6
- -1 rare earth ions Chemical class 0.000 description 6
- 229910052693 Europium Inorganic materials 0.000 description 3
- 150000004767 nitrides Chemical class 0.000 description 3
- 230000006798 recombination Effects 0.000 description 3
- 238000005215 recombination Methods 0.000 description 3
- 230000003595 spectral effect Effects 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- 229910052692 Dysprosium Inorganic materials 0.000 description 2
- 229910052771 Terbium Inorganic materials 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 150000001768 cations Chemical class 0.000 description 2
- 239000002800 charge carrier Substances 0.000 description 2
- 230000005281 excited state Effects 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000001429 visible spectrum Methods 0.000 description 2
- 229910052691 Erbium Inorganic materials 0.000 description 1
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 1
- 229910001199 N alloy Inorganic materials 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 229910052775 Thulium Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- NWAIGJYBQQYSPW-UHFFFAOYSA-N azanylidyneindigane Chemical compound [In]#N NWAIGJYBQQYSPW-UHFFFAOYSA-N 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000000875 corresponding effect Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005274 electronic transitions Effects 0.000 description 1
- OGPBJKLSAFTDLK-UHFFFAOYSA-N europium atom Chemical compound [Eu] OGPBJKLSAFTDLK-UHFFFAOYSA-N 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 230000005283 ground state Effects 0.000 description 1
- 239000003446 ligand Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000002040 relaxant effect Effects 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- GZCRRIHWUXGPOV-UHFFFAOYSA-N terbium atom Chemical compound [Tb] GZCRRIHWUXGPOV-UHFFFAOYSA-N 0.000 description 1
- VLCQZHSMCYCDJL-UHFFFAOYSA-N tribenuron methyl Chemical compound COC(=O)C1=CC=CC=C1S(=O)(=O)NC(=O)N(C)C1=NC(C)=NC(OC)=N1 VLCQZHSMCYCDJL-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/04—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction
- H01L33/06—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction within the light emitting region, e.g. quantum confinement structure or tunnel barrier
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/26—Materials of the light emitting region
- H01L33/30—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table
- H01L33/32—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table containing nitrogen
- H01L33/325—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table containing nitrogen characterised by the doping materials
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/08—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body
Definitions
- This invention pertains to solid state light sources based on GaN-AIGaN- InGaN alloys with rare earth doping.
- Gallium, aluminum and indium nitride alloys with terbium, europium and/or other rare earth ions have been previously proposed as active layers for phosphoriess white light emitting double heterostructure (DHS) LEDs (See, US Patent Publication No. 2005/0253162).
- DHS white light emitting double heterostructure
- Luminescence from various activator ions doped into a nitride semiconductor alloy is based on energy transfer from host material (the alloy) to the activator ion (the rare earth). The efficiency of this energy transfer depends on several factors including the band gap (BG) energies of the host or band gap emission (BGE). It is possible to optimize the electronic structure and BGE energy of the host for one particular type of dopant ion by changing the alloy composition so that the luminescence efficiency of this host-activator combination is at its maximum. However, for generating better quality white light, more than one activator type for multiple color components is needed. It may be difficult to achieve optimum conditions for the energy transfer to multiple activators, it may prove equally hard to simultaneously incorporate notable concentrations of various activator ions in the same lattice for efficacious white light emission.
- BG band gap
- BGE band gap emission
- a light-emitting diode having a light-emitting surface, the light-emitting diode comprising a plurality of quantum well layers wherein one or more of the quantum well layers is doped with one or more activator ions that emit light and the quantum well layers are arranged in a sequence whereby the light emission from a lower quantum wel! layer is not significantly absorbed by quantum well layers between the lower quantum well layer and the light emitting surface.
- the quantum well layers are arranged in a sequence of increasing band gap energy and comprise an AIGaInN alloy.
- the light-emitting diode includes a stack of quantum well layers comprising a first quantum well layer that emits a red light and is doped with Eu 3+ , a second quantum well layer that emits a yellow light and is doped with Dy 3+ , a third quantum well layer that emits a green light and is doped with Tb 3+ , and a fourth quantum well layer that emits a blue light, the quantum well layers being arranged in order according to their emission wavelength wherein the first quantum well layer is furthest from the light-emitting surface.
- the Figure is illustrates a AIGaln-based multiple quantum well (MQW) structure with a combination of active regions emitting in red (Eu 3+ ), yellow (Dy 3+ ), green (Tb 3+ ), and blue (undoped) spectral regions.
- MQW multiple quantum well
- Active layers of DHSs (or quantum wells) in nitride-based LEDs doped with the rare earth ions of more than one type are expected to emit light that is perceived as white due to simultaneous luminescence from the host and dopants in various parts of the visible spectrum.
- the recombination of injected electrons and holes may involve the dopant ion with a probability determined by a number of factors.
- White light is formed with or without a significant contribution due to the host alloy itself (BGE, typically in the blue spectral range), depending on the choice and concentration of these activator ions.
- Each rare earth ion in this case Pr, Eu, Tb, Dy, Er or Tm in a +3 state
- the transitions involving excited states of the outer orbitals of the rare earth (such as 5d) or host ions (as in charge transfer) may shift significantly in energy with various cation-ligand combinations of the lattice. This affects strongly the luminescence efficiency of each ion in that lattice.
- the energy transfer from the host lattice to the dopant ion may proceed via more than one mechanism with the effectiveness of each channel depending on several factors. Some of them, like the position of host energy levels, the size of the BG and hence also the BGE energy relative to the positioning of ground and excited states of the dopant can be modified by varying the host alloy composition. This allows for the optimization of dopant luminescence efficiency in nitride alloys via changes in cation composition, for example by tuning the Ga/ln ratio in In x Ga 1 ⁇ x N. However, it is unlikely that rare earth ions emitting through very different excitation mechanisms (cf. Eu 3+ and Tb 34 ) will achieve optimum efficiencies for the same alloy composition.
- a DHS consists of an active layer sandwiched between the two cladding layers that confine the charge carriers to the recombination region due to a larger band gap (an alloy with different cation composition and no rare earth doping) than that of the active region. Band discontinuities much larger than kT help in concentrating the electrons and holes for effective recombination (quantum efficiency).
- the thickness of the active layer in a typical DHS is application optimized and ranges from ⁇ 100nm to ⁇ 1Q.00.nm while in a QW it is of several nanometers. QWs are typically used in multiples (MQWs). For the latter, the confinement layers control the flow of carriers between the adjacent wells.
- each single QW would constitute a combination of the dopant rare earth ion and Al x ln y Gai -x - y N alloy with an optimized composition (x,y) to produce maximum desired luminescence efficiency of the desired color (or color combination with alloy emission).
- the QWs 5 in the LED 7 are stacked in the sequence of increasing band gap and emission energy so that the red emission (Eu 3+ ) from the lowest QW in the stack is furthest from the topmost, light-emitting surface 2. (See, energy diagram to left of LED 7). This way, the re-absorption of light by the host alloys is largely avoided.
- the choice of activators and their concentrations, number of QWs of each type as well as all other parameters will be determined corresponding to the application and considering the maximum possible efficacy.
- the AIGaln-based MQW structure is constructed with active regions emitting in red (Eu 3+ ), yellow (Dy 3+ ), green (Tb 3+ ), and blue (undoped) spectral regions and are stacked in order according to their emission wavelength with the red-emitting layer being furthest from the LED's light-emitting surface.
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Luminescent Compositions (AREA)
- Led Devices (AREA)
Abstract
A light-emitting diode having a light-emitting surface is described. The light-emitting diode comprises a series of quantum well layers wherein one or more of the quantum well layers is doped with one or more activator ions that emit light and the quantum well layers are arranged in a sequence whereby the light emission from a lower quantum well layer is not significantly absorbed by quantum well layers between the lower quantum well layer and the light-emitting surface.
Description
LIGHT EMITTING DIODE BASED ON MULTIPLE DOUBLE-HETEROSTRUCTURES (QUANTUM WELLS) WITH RARE EARTH DOPED ACTIVE REGIONS
Cross Reference to Related Appiication
[0001] This appiication claims the benefit of U.S. Provisional Appiication No.
60/938,209, filed 5/16/2007.
Technical Field
[0002] This invention pertains to solid state light sources based on GaN-AIGaN- InGaN alloys with rare earth doping. Gallium, aluminum and indium nitride alloys with terbium, europium and/or other rare earth ions have been previously proposed as active layers for phosphoriess white light emitting double heterostructure (DHS) LEDs (See, US Patent Publication No. 2005/0253162).
Background of the Invention
[0003] Luminescence from various activator ions doped into a nitride semiconductor alloy is based on energy transfer from host material (the alloy) to the activator ion (the rare earth). The efficiency of this energy transfer depends on several factors including the band gap (BG) energies of the host or band gap emission (BGE). It is possible to optimize the electronic structure and BGE energy of the host for one particular type of dopant ion by changing the alloy composition so that the luminescence efficiency of this host-activator combination is at its maximum. However, for generating better quality white light, more than one activator type for multiple color components is needed. It may be difficult to achieve optimum conditions for the energy transfer to multiple activators, it may prove equally hard to simultaneously incorporate notable concentrations of various activator ions in the same lattice for efficacious white light emission.
Summary of the invention
[0004] It is an object of the invention to obviate the disadvantages of the prior art.
[0005] it is another object of the invention to provide a light-emitting diode having a novel multiple quantum well structure.
[0006] it is a further object of the invention to provide a white-light-emitting diode.
[0007] In accordance with these and other objects and advantages, there is provided a light-emitting diode having a light-emitting surface, the light-emitting diode comprising a plurality of quantum well layers wherein one or more of the quantum well layers is doped with one or more activator ions that emit light and the quantum well layers are arranged in a sequence whereby the light emission from a lower quantum wel! layer is not significantly absorbed by quantum well layers between the lower quantum well layer and the light emitting surface. Preferably, the quantum well layers are arranged in a sequence of increasing band gap energy and comprise an AIGaInN alloy.
[0008] In another aspect of the invention, the light-emitting diode includes a stack of quantum well layers comprising a first quantum well layer that emits a red light and is doped with Eu3+, a second quantum well layer that emits a yellow light and is doped with Dy3+, a third quantum well layer that emits a green light and is doped with Tb3+, and a fourth quantum well layer that emits a blue light, the quantum well layers being arranged in order according to their emission wavelength wherein the first quantum well layer is furthest from the light-emitting surface.
Brief Description of the Drawing
[0009] The Figure is illustrates a AIGaln-based multiple quantum well (MQW) structure with a combination of active regions emitting in red (Eu3+), yellow (Dy3+), green (Tb3+), and blue (undoped) spectral regions.
Detailed Description of the Invention
[0010] Generation of white light with a desired correlated color temperature (CCT) and color rendering index (CRl) is achievable in devices having multiple active layers (or thin quantum wells, QWs). Each layer is based on an alloy composition optimized
for a particular host-activator combination which produces the desired color with maximum quantum efficiency. Such layers are stacked according to their emission wavelengths and the number and thickness of layers from each type is determined by the overall optimum conditions for desired optica! and electrical performance.
[0011] Active layers of DHSs (or quantum wells) in nitride-based LEDs doped with the rare earth ions of more than one type (for example, trivalent Tm+Tb+Eu or Dy+Eu, to name only two combinations) are expected to emit light that is perceived as white due to simultaneous luminescence from the host and dopants in various parts of the visible spectrum. Instead of relaxing across the BG as in pure semiconductors, the recombination of injected electrons and holes may involve the dopant ion with a probability determined by a number of factors. White light is formed with or without a significant contribution due to the host alloy itself (BGE, typically in the blue spectral range), depending on the choice and concentration of these activator ions. Each rare earth ion (in this case Pr, Eu, Tb, Dy, Er or Tm in a +3 state) exhibits multiple emission lines across the visible spectrum arising from 4f-4f electronic transitions. These transitions change very little from host to host and due to one or two dominant transitions generate a light of a particular color characteristic to that ion (e.g. red for Eu3+, green for Tb3+ or Er3+). At the same time, the transitions involving excited states of the outer orbitals of the rare earth (such as 5d) or host ions (as in charge transfer) may shift significantly in energy with various cation-ligand combinations of the lattice. This affects strongly the luminescence efficiency of each ion in that lattice.
[0012] The energy transfer from the host lattice to the dopant ion may proceed via more than one mechanism with the effectiveness of each channel depending on several factors. Some of them, like the position of host energy levels, the size of the BG and hence also the BGE energy relative to the positioning of ground and excited states of the dopant can be modified by varying the host alloy composition. This allows for the optimization of dopant luminescence efficiency in nitride alloys via changes in cation composition, for example by tuning the Ga/ln ratio in InxGa1^xN. However, it is unlikely
that rare earth ions emitting through very different excitation mechanisms (cf. Eu3+ and Tb34) will achieve optimum efficiencies for the same alloy composition.
[0013] A DHS consists of an active layer sandwiched between the two cladding layers that confine the charge carriers to the recombination region due to a larger band gap (an alloy with different cation composition and no rare earth doping) than that of the active region. Band discontinuities much larger than kT help in concentrating the electrons and holes for effective recombination (quantum efficiency). The thickness of the active layer in a typical DHS is application optimized and ranges from ~100nm to ~1Q.00.nm while in a QW it is of several nanometers. QWs are typically used in multiples (MQWs). For the latter, the confinement layers control the flow of carriers between the adjacent wells. Their height and thickness, in turn, are dictated by achieving efficient, homogeneous charge carrier distribution. Higher barriers may be used for overall confinement of electrons and holes in the MQW region. Coupling or stacking the DHSs follows the same general rationale but since providing homogeneous current distribution and extracting of the light becomes increasingly difficult for thick layers, we describe the structure from here on as consisting of QWs.
[0014] In present case, each single QW would constitute a combination of the dopant rare earth ion and AlxlnyGai-x-yN alloy with an optimized composition (x,y) to produce maximum desired luminescence efficiency of the desired color (or color combination with alloy emission).
[0015] As shown in the Figure, the QWs 5 in the LED 7 are stacked in the sequence of increasing band gap and emission energy so that the red emission (Eu3+) from the lowest QW in the stack is furthest from the topmost, light-emitting surface 2. (See, energy diagram to left of LED 7). This way, the re-absorption of light by the host alloys is largely avoided. The choice of activators and their concentrations, number of QWs of each type as well as all other parameters will be determined corresponding to the application and considering the maximum possible efficacy. In a preferred embodiment, the AIGaln-based MQW structure is constructed with active regions emitting in red
(Eu3+), yellow (Dy3+), green (Tb3+), and blue (undoped) spectral regions and are stacked in order according to their emission wavelength with the red-emitting layer being furthest from the LED's light-emitting surface.
[0016] While there have been shown and described what are at present considered to be preferred embodiments of the invention, it will be apparent to those skilled in the art that various changes and modifications can be made herein without departing from the scope of the invention as defined by the appended claims.
Claims
1. A light-emitting diode having a ϋght-emitting surface, the Sight-emitting diode comprising a plurality of quantum well layers wherein one or more of the quantum well layers is doped with one or more activator ions that emit light and the quantum well layers are arranged in a sequence whereby the light emission from a lower quantum well layer is not significantly absorbed by quantum well layers between the lower quantum well layer and the light emitting surface.
2. The light-emitting diode of claim 1 wherein the quantum well layers are arranged in a sequence of increasing band gap energy.
3. The light-emitting diode of claim 1 wherein the quantum well layers are comprised of an AIGaInN alloy.
4. The light-emitting diode of claim 1 wherein each quantum well layer that is doped with an activator ion contains a different type of activator ion than the other quantum well layer(s) that are doped with activator ion(s).
5. The light-emitting diode of claim 1 wherein the quantum well layers comprise at least one red-emitting, one yellow-emitting, one green-emitting and one blue-emitting quantum layer.
6. The light-emitting diode of claim 5 wherein the red-, yellow-, green- and blue- emitting quantum wells are stacked in order according to their emission wavelength with the red-emitting quantum layer being furthest from the light-emitting surface.
7. A light-emitting diode having a light-emitting surface, the light-emitting diode including a stack of quantum well layers comprising a first quantum well layer that emits a red light and is doped with Eu3+, a second quantum well layer that emits a yellow light and is doped with Dy3+, a third quantum well layer that emits a green light and is doped with Tb3+, and a fourth quantum well layer that emits a blue light, the quantum well layers being arranged in order according to their emission wavelength wherein the first quantum well layer is furthest from the light-emitting surface.
8. The light-emitting diode of claim 7 wherein the quantum well layers are comprised of an AIGaInN alloy.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US93820907P | 2007-05-16 | 2007-05-16 | |
| US60/938,209 | 2007-05-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2008144337A1 true WO2008144337A1 (en) | 2008-11-27 |
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ID=39540715
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/US2008/063597 WO2008144337A1 (en) | 2007-05-16 | 2008-05-14 | Light emitting diode based on multiple double-heterostructures (quantum wells) with rare earth doped active regions |
Country Status (1)
| Country | Link |
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| WO (1) | WO2008144337A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110444644A (en) * | 2019-07-26 | 2019-11-12 | 浙江大学 | A kind of electroluminescent device of enhancing silicon substrate Er ions ZnO film and preparation method |
| FR3119709A1 (en) * | 2021-02-09 | 2022-08-12 | Commissariat A L'energie Atomique Et Aux Energies Alternatives | LIGHT EMITTING DIODE COMPRISING EMISSIVE REGIONS INCLUDING RARE EARTH IONS |
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| JP2000091703A (en) * | 1998-09-11 | 2000-03-31 | Sony Corp | Semiconductor light emitting element and its manufacture |
| EP1220334A2 (en) * | 2000-12-28 | 2002-07-03 | Ngk Insulators, Ltd. | A semiconductor light-emitting element |
| US20050206312A1 (en) * | 2004-03-18 | 2005-09-22 | Samsung Electro-Mechanics Co., Ltd. | Monolithic white light emitting device |
| WO2007021017A1 (en) * | 2005-08-17 | 2007-02-22 | Ngk Insulators, Ltd. | Semiconductor layered structure and its method of formation, and light emitting device |
-
2008
- 2008-05-14 WO PCT/US2008/063597 patent/WO2008144337A1/en active Application Filing
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000091703A (en) * | 1998-09-11 | 2000-03-31 | Sony Corp | Semiconductor light emitting element and its manufacture |
| EP1220334A2 (en) * | 2000-12-28 | 2002-07-03 | Ngk Insulators, Ltd. | A semiconductor light-emitting element |
| US20050206312A1 (en) * | 2004-03-18 | 2005-09-22 | Samsung Electro-Mechanics Co., Ltd. | Monolithic white light emitting device |
| WO2007021017A1 (en) * | 2005-08-17 | 2007-02-22 | Ngk Insulators, Ltd. | Semiconductor layered structure and its method of formation, and light emitting device |
Non-Patent Citations (1)
| Title |
|---|
| YAMADA M ET AL: "PHOSPHOR FREE HIGH-LUMINOUS-EFFICIENCY WHITE LIGHT-EMITTING DIODES COMPOSED OF INGAN MULTI-QUANTUM WELL", JAPANESE JOURNAL OF APPLIED PHYSICS, JAPAN SOCIETY OF APPLIED PHYSICS, TOKYO.; JP, vol. 41, no. 3A, PART 02, 1 March 2002 (2002-03-01), pages L246 - L248, XP001186615, ISSN: 0021-4922 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110444644A (en) * | 2019-07-26 | 2019-11-12 | 浙江大学 | A kind of electroluminescent device of enhancing silicon substrate Er ions ZnO film and preparation method |
| FR3119709A1 (en) * | 2021-02-09 | 2022-08-12 | Commissariat A L'energie Atomique Et Aux Energies Alternatives | LIGHT EMITTING DIODE COMPRISING EMISSIVE REGIONS INCLUDING RARE EARTH IONS |
| WO2022171948A1 (en) * | 2021-02-09 | 2022-08-18 | Commissariat à l'énergie atomique et aux énergies alternatives | Light-emitting diode comprising emitting regions including rare earth ions |
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