CN1943051A - Light emitting device with fluorescent material - Google Patents
Light emitting device with fluorescent material Download PDFInfo
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- CN1943051A CN1943051A CNA2006800001116A CN200680000111A CN1943051A CN 1943051 A CN1943051 A CN 1943051A CN A2006800001116 A CNA2006800001116 A CN A2006800001116A CN 200680000111 A CN200680000111 A CN 200680000111A CN 1943051 A CN1943051 A CN 1943051A
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Abstract
A light emitting device includes a transparent substrate (1) having first and second surfaces, a semiconductor layer (2-6) provided on the first surface, a first light emission layer (11) provided over the semiconductor layer (2-6) and emitting first ultraviolet light including a wavelength corresponding to an energy larger than a forbidden bandwidth of a semiconductor of the semiconductor layer, a second light emission layer (8) provided between the first light emission layer (11) and the semiconductor layer (2-6), absorbing the first ultraviolet light emitted from the first light emission layer (11), and emitting second ultraviolet light including a wavelength corresponding to an energy smaller than the forbidden bandwidth of the semiconductor of the semiconductor layer (2-6), and first (18) and second (19) electrodes provided to apply electric power to the first light emission layer (11).
Description
Technical field
The present invention relates to a kind of utilization based on the luminescent device of the III-V compound semiconductor of nitride or utilize the luminescent device of fluorescent material.
Background technology
By utilizing the light-emitting diode (LED) that forms by GaN and its mixed crystal, attempted based on the emission of polytype light and obtained white light with different peak wavelengths, replacement conventional white fluorescent lamp (referring to, for example: Japanese Patent Application Laid-Open publication number 2001-352098).In the disclosure, the GaN optical excitation emission layer by the blue-light excited Si that produces in Multiple Quantum Well (MQW) luminescent layer of light-emitting diode mixes with the generation gold-tinted, and utilizes these light to have the fact of complementary colours relation, obtains white light thus.Yet, can not produce redness in the luminescent device of in above-mentioned disclosing, being introduced, make the color rendering deterioration of light thus, this luminescent device can fully replace the conventional white fluorescent lamp hardly.
In recent years, the LED by determining GaN and its mixed crystal is as excitaton source and make this LED combine resulting white lamps with fluorescent material to be used for throwing light on.Yet, exist Billy with the efficient of the white lamps of the conventional fluorescent lamp difference of mercury discharge pipe and the problem of color rendering.This is because employed fluorescent material has wide spectral width and low light emission effciency in this white lamps.Particularly, modal reason is the low luminous efficiency of red fluorescent material.
In the white fluorescent lamp of routine, use (for example, the Y such as oxide that wherein added trivalent rare earth element Eu
2O
3: Eu3+) as red fluorescent material.By the intrinsic interior nuclear transition of trivalent rare earth element Eu itself, this oxide that has wherein added Eu demonstrates near the red light emission that has very narrow Wavelength distribution 620nm.Because Wavelength distribution is narrow, so the not loss that is caused by the emission of the light in the low long wavelength region of luminance, this goes far towards to raise the efficiency and color rendering.
This interior nuclear transition of trivalent rare earth element Eu atom is forbidden transition, and when exciting by the light with the short wavelength who is not more than 350nm, efficient increases significantly.Therefore, when utilizing the LED that forms by GaN and its mixed crystal, because the light emission wavelength of GaN is 365nm, so must excite with the wavelength shorter than this wavelength.Yet, under the situation that shortens the light emission wavelength, can think, because for example the GaN that forms on Sapphire Substrate etc. is light absorbing former thereby can not obtain sufficient efficient.
As mentioned above, using by semiconductor for example under the situation of the excitated red fluorescent material of light-emitting diode that forms such as GaN and its mixed crystal, the light emission effciency of red fluorescent material is low.Can think,,, can not obtain sufficient efficient owing to passing through for example reasons such as light absorption of GaN of semiconductor even shortened the light emission wavelength in order to improve the light emission effciency.Therefore, by using, can not make red fluorescent material luminous effectively by the semiconductor light-emitting diode that forms such as GaN and its mixed crystal for example.In addition, combine with any other visible fluorescence material by making red fluorescent material, very difficult realization has the luminescent device of high efficiency and high color rendering.
Therefore, need to realize making the effectively luminous luminescent device of red fluorescent material or utilize light-emitting diode and the luminescent device of good fluorescent material aspect efficient and color rendering.
Summary of the invention
According to the present invention, a kind of luminescent device is provided, it comprises:
Transparent substrates, it has first surface and second surface;
Semiconductor layer, it is arranged on described first first type surface of described transparent substrates;
First light-emitting layer, it is arranged on the described semiconductor layer, and emission comprises and first ultraviolet light greater than the corresponding wavelength of the energy of the semi-conductive energy gap of described semiconductor layer;
Second light-emitting layer, it is arranged between described first light-emitting layer and the described semiconductor layer, absorption is from described first ultraviolet light of described first light-emitting layer emission, and emission comprises and second ultraviolet light less than the corresponding wavelength of the energy of the semi-conductive energy gap of described semiconductor layer; And
First electrode and second electrode, it is for applying electric power setting to described first light-emitting layer.
Description of drawings
Fig. 1 shows the sectional view according to the structure of the luminescent device of first embodiment of the invention;
Fig. 2 shows red fluorescent material YVO
4: Er
3+The performance plot of excitation spectrum;
Fig. 3 shows the sectional view according to the structure of the luminescent device of the modification of first embodiment;
Fig. 4 shows the sectional view according to the structure of the luminescent device of second embodiment of the invention;
Fig. 5 shows the sectional view according to the structure of the luminescent device of third embodiment of the invention;
Fig. 6 shows the sectional view according to the structure of the luminescent device of fourth embodiment of the invention;
Fig. 7 shows the sectional view according to the structure of the luminescent device of fifth embodiment of the invention;
Fig. 8 shows the sectional view according to the structure of the luminescent device of sixth embodiment of the invention;
Fig. 9 shows the sectional view according to the structure of the luminescent device of seventh embodiment of the invention;
Figure 10 shows the sectional view according to the structure of the luminescent device of eighth embodiment of the invention; And
Figure 11 shows the sectional view according to the structure of the luminescent device of ninth embodiment of the invention.
Embodiment
Now, embodiments of the invention will be described hereinafter with reference to the accompanying drawings.
(first embodiment)
As shown in fig. 1, the luminescent device according to present embodiment is the light-emitting diode that is formed by formed GaN based compound semiconductor on Sapphire Substrate.That is, be on the substrate 1 of sapphire c face on its surface, stacked in regular turn AlN resilient coating a 2 (concentration of carbon: 3 * 10 with high carbon concentration
18To 5 * 10
20/ cm
3, film thickness: 3 to 20nm), highly purified the 2nd AlN resilient coating 3 (concentration of carbon: 1 * 10
18To 3 * 10
18/ cm
32 μ m), the GaN resilient coating 4 of non-doping (film thickness: 3 μ m), Si doped n type GaN contact layer 5 (Si concentration: 1 * 10, film thickness:
18To 5 * 10
18/ cm
3, film thickness: 2 to 5 μ m).
In addition, on Si doped n type GaN contact layer 5, stacked in regular turn Si doped n type Al
0.05Ga
0.95N first limiting layer 6 (the Si concentration: 1 * 10
18/ cm
3, film thickness: 20nm), Si doped n type GaN first absorbed layer 7 (the Si concentration: 1 * 10
18/ cm
3, film thickness: 100nm), Si doped n type GaInN optical excitation near ultraviolet emission layer 8 (Si concentration: 1 * 10
18/ cm
3, film thickness: 3.5nm, wavelength: 380nm), Si doped n type GaN second absorbed layer 9 (the Si concentration: 1 * 10
18/ cm
3, film thickness: 100nm), Si doped n type Al
0.11Ga
0.89N second limiting layer 10 (the Si concentration: 1 * 10
18/ cm
3, film thickness: 20nm), Si doped n type Al
0.06Ga
0.94The N electric current injects ultraviolet emission layer 11 (Si concentration: 1 * 10
18/ cm
3, film thickness: 3.0nm, wavelength: 345nm), the Al of non-doping
0.11Ga
0.89N wall 12 (film thickness: 20nm), Mg doped p type Al
0.28Ga
0.72N electron barrier layer 13 (Mg concentration: 1 * 10
19/ cm
3, film thickness: 10nm), Mg doped p type Al
0.11Ga
0.89N contact layer 14 (Mg concentration: 1 * 10
19/ cm
3, film thickness: 100nm), high concentration Mg doped p type Al
0.11Ga
0.89N contact layer 15 (Mg concentration: 2 * 10
20/ cm
3, film thickness: 20nm), high concentration Si doped n type Al
0.11Ga
0.89N contact layer 16 (Si concentration: 1 * 10
20/ cm
3, film thickness: 20nm) and the n type Al of silicon doping
0.11Ga
0.89N contact layer 17 (Si concentration: 5 * 10
18/ cm
3, film thickness: 100nm).
On the upper surface of the exposed portions serve of Si doped n type GaN contact layer 5, form the n lateral electrode 18 that constitutes by by the resulting composite membrane of deposit Ti (0.05 μ m)/Pt (0.05 μ m)/Au (1.0 μ m) in regular turn.Similarly, at the n of silicon doping type Al
0.11Ga
0.89On the upper surface of the part of N contact layer 17, form by passing through the p lateral electrode 19 of the resulting composite membrane formation of deposit Ti (0.05 μ m)/Pt (0.05 μ m)/Au (1.0 μ m) in regular turn.
AlN resilient coating 2 with high carbon concentration is used to relax the shape difference of crystal and substrate, reduces screw dislocation especially.In addition, highly purified the 2nd AlN resilient coating 3 has the surface of the planarization of atom level, and is the layer of defective of GaN resilient coating 4 that reduces thereon the non-doping of growth, and can be preferably the thickness of this layer 3 be increased to greater than 1 μ m.In addition, for fear of the warpage that is caused by strain, the thickness that is not more than 4 μ m is desirable.Highly purified the 2nd AlN resilient coating 3 is not limited to AlN, can adopt Al
xGa
1-xN (0.8≤x≤1), but the warpage of its compensate for wafer.
The GaN resilient coating 4 of non-doping is used to reduce the defective of three-dimensional island growth on highly purified the 2nd AlN resilient coating.In order to make the growing surface planarization, the average film thickness of the GaN resilient coating 4 of non-doping must be equal to or higher than 2 μ m.With regard to repeatable and minimizing warpage, 4 to 10 μ m are suitable as the total film thickness of the GaN resilient coating 4 of non-doping.
In the luminescent device according to present embodiment, electronics is from n type Al
0.11Ga
0.89N second limiting layer 10 is injected into n type Al
0.06Ga
0.94In the N ultraviolet emission layer 11, and the hole is from Mg doped p type Al
0.28Ga
0.72N electron barrier layer 13 passes Al
0.11Ga
0.89 N wall 12 is injected into same n type Al
0.06Ga
0.94In the N ultraviolet emission layer 11, and from this Al
0.06Ga
0.9411 emission of N ultraviolet emission layer have the ultraviolet light of 345nm wavelength.Ultraviolet light transmission towards the emission of p lateral electrode 19 sides is passed from Al
0.11Ga
0.89N wall 12 is to the n type Al of silicon doping
0.11Ga
0.89Each layer of N contact layer 17, and outwards discharge effectively.This be because these layers in each layer energy gap greater than with the corresponding energy of ultraviolet light wavelength that will launch.
On the other hand, ultraviolet light towards the emission of substrate 1 side is absorbed in Si doped n type GaN second absorbed layer 9 and Si doped n type GaN first absorbed layer 7, electronics that is produced and hole are compound in Si doped n type GaInN optical excitation near ultraviolet emission layer 8, thus the black light of emission 380nm.Because the energy of this light is less than the energy gap of GaN, thus its launch to the outside from substrate 1 effectively, and not by the absorptions such as GaN resilient coating 4 of n type GaN contact layer 5, non-doping.This light also towards the emission of p lateral electrode 19 sides, pass from Si doped n type GaN second absorbed layer 9 to n type Al effectively by transmission
0.11Ga
0.88 N contact layer 17 each the layer and be not absorbed, and effectively to the outside the emission.
As the total film thickness of n type GaN first absorbed layer 7 and n type GaN second absorbed layer, in view of absorption efficiency with excite the compromise of carrier loss, 0.1 to 0.3 μ m is suitable.In making absorption portion and luminous component separated structures by this way, can reduce the film thickness of GaInN light-emitting layer.When reducing film thickness in this way, can alleviate the influence of the piezoelectric field that causes by strain, thereby because the reduction of the carrier mobility that alloy scattering causes becomes quite big.As a result, reduced the speed of capturing, thereby suppressed to launch compound by the non-light that crystal defect causes to defective.Therefore, can obtain high light emission effciency.
Fig. 2 shows a kind of red fluorescent material YVO that is used for typical high-pressure mercury gas lamp
4: Er
3+The performance plot of excitation spectrum.As shown in Figure 2, when exciting with the light with the short wavelength who is not more than 350nm, emission effciency increases suddenly.This is because the interior nuclear transition of trivalent rare earth element Eu atom is forbidden transition, and need with have relevant the exciting of more high-octane outer nuclear layer.According to the luminescent device of present embodiment, excite fluorescent material (for example, the YVO that has as the trivalent Eu of launching centre effectively towards the ultraviolet light of the 345nm of p lateral electrode 19 sides emissions
4: Er
3+), and be transformed into the light of narrow Wavelength distribution with about 620nm.That is to say,, can obtain red visible light effectively by having the short wavelength's who is not more than 350nm ultraviolet light.
In addition, be transmitted in the black light of the 380nm that is produced in the Si doped n type GaInN optical excitation near ultraviolet emission layer 8 towards substrate 1 side or p lateral electrode 19 sides, and also can effectively utilize this light.For example, can utilize this light to come the fluorescent material of the visible light of excitation-emission except that red light, thereby obtain the visible light except that red light effectively.Luminescent device according to present embodiment is combined with the fluorescent material of red fluorescent material or any other color, can obtain white light or have versicolor light.To introduce the White LED that produces white light below.
In addition, according to the luminescent device of present embodiment, by high concentration Mg doped p type Al
0.11Ga
0.89N contact layer 15 and high concentration Si doped n type Al
0.11Ga
0.89N contact layer 16 forms tunnel junction, so even under the condition of pn knot reverse operation, also available low pressure drop encourages.Therefore, can use n type AlGaN, thereby realize high efficiency and low voltage operating as contact layer and current-diffusion layer on p lateral electrode 19 sides with low resistance and high grade of transparency.
Manufacture method according to the luminescent device of present embodiment will be described now.At first, Sapphire Substrate 1 is installed on the pedestal, this pedestal also is used as the heater of MOCVD equipment.Introduce 2 * 10 from gas inlet tube at any one time
-2/ m
3High-purity hydrogen (H
2) gas, with the atmosphere in the exchange reaction pipe.Then, internal pressure is set to 10 to 30kPa scope.Subsequently, at hydrogen (H
2) heating Sapphire Substrate 1 in the gas, make its surface be cleaned.
Then, under 1150 to 1200 ℃ underlayer temperature, introduce ammonia (NH
3) gas and trimethyl aluminium (Al (CH
3)
3) steam, make an AlN resilient coating 2 growths 3 to 20nm with high carbon concentration.At this moment, for the disordered state of the crystal orientation that reduces an AlN resilient coating 2, very important to the control of the V group element raw material that will enter reaction tube and the raw-material supply ratio of III family element (V/III ratio).Need 0.7 to 50 the V/III ratio ranges high quality film of atresia of growing, and wish the V/III ratio is controlled in 1.2 to 2.4 the scope, so that obtain to have the abundant quality of splendid repeatability.Then, underlayer temperature is elevated to 1250 to 1350 ℃, makes highly purified the 2nd AlN resilient coating 3 growth 1 to 5 μ m, and make its flattening surface.For highly purified the 2nd AlN resilient coating 3 of growing, the V/III ratio is set at about 250 to 10000.
In addition, underlayer temperature is set at than high 1150 to 1250 ℃ of conventional GaN growth temperature, thereby makes GaN resilient coating 4 growths of non-doping.After this, make growth temperature be reduced to 1100 to 1200 ℃, and add monosilane (SiH4) gas, so that 5 growths of Si doped n type GaN contact layer.When making these each layer growths of growth on highly purified the 2nd AlN resilient coating 3, hope is set at the V/III ratio and is not less than 100 height ratio.
Then, underlayer temperature is being set at 1000 ℃ after 1050 ℃, the component structure part that makes light-emitting diode is (from n type Al
0.05Ga
0.95N first limiting layer 6 to n type Al
0.11Ga
0.89Each layer of N contact layer 17) growth.As III family raw material, adopt trimethyl aluminium (Al (CH
3)
3), trimethyl gallium (Ga (CH
3)
3) or trimethyl indium (In (CH
3)
3).As V family raw material, adopt ammonia (NH
3) gas.As n type doping raw material, adopt monosilane (SiH
4) gas.As p type doping raw material, adopt bis-cyclopentadienyl magnesium (Cp
2Mg) or bis-methylcyclopentadienyl magnesium (M
2Cp
2Mg).
Then, by reactive ion etching (RIE), the layer of each growth of selective etch makes part expose Si doped n type GaN contact layer 5, and forms the n lateral electrode 18 that is made of the Ti/Pt/Au composite membrane by peeling off (liff-off) method on the part of exposed portions serve.By peeling off method at the n of silicon doping type Al
0.11Ga
0.89The same p lateral electrode 19 that constitutes by the Ti/Pt/Au composite membrane that forms on the part of N contact layer 17.Then, cut to obtain discrete LED device by cleavage, diamond blade etc.
As mentioned above,, needn't use the specific post-order process of removing substrate and GaN resilient coating, go out to have the efficient ultraviolet light-emitting diode of high yield thus with low-cost production according to the manufacture method of the luminescent device of present embodiment.
Simultaneously, as mentioned above, in first embodiment, the ultraviolet light that has the 345nm wavelength from 11 emission of AlGaN ultraviolet emission layer, all have in Si doped n type GaN second absorbed layer 9 of the energy gap littler and Si doped n type GaN first absorbed layer 7 towards the ultraviolet light of p lateral electrode 19 sides and substrate 1 side emission and to be absorbed than the energy of this ultraviolet light, and electronics that is produced and hole are compound in Si doped n type GaInN optical excitation near ultraviolet emission layer 8, thus the black light of emission 380nm.Because the energy of the black light of this 380nm is less than the energy gap of GaN, so it is launched to the outside from substrate 1 effectively, and in the GaN resilient coating 4 of n type GaN contact layer 5, non-doping etc., be not absorbed, and also towards 19 emissions of p lateral electrode.
Yet, first embodiment is not limited to combinations thereof, and it can be configured to from top, and 11 emissions of first light-emitting layer have for example black light of the longer wavelength of 370nm, and launch for example black light of 380nm from second light-emitting layer 8 that is arranged at first light-emitting layer, 11 belows.That is to say, because the light of being launched from first light-emitting layer 11 mainly comprises the light that has with near the corresponding wavelength of the energy in the forbidden band of GaN, but also comprise the light that has with greater than the corresponding wavelength of the energy in the forbidden band of GaN, this light is absorbed in GaN absorbed layer 9 and 7, and the light emission effciency reduces.Yet this light is absorbed in the quantum well of second light-emitting layer 8, and the electronics that is produced and hole are compound in second light-emitting layer 8, thus the black light of emission 380nm.
Fig. 3 is the sectional view according to the luminescent device of this modification.In the drawings, identical reference number represents to be equal to the part of those parts among Fig. 1, thereby has omitted repeated explanation.Reference number 1 to 5 in the bottom of this luminescent device basically with Fig. 1 in identical, 2 μ m), the GaN resilient coating 4 of non-doping (film thickness: 2 μ m) and Si doped n type GaN contact layer 5 (film thickness: 3 μ m) (the film thickness: 5nm), highly purified the 2nd AlN resilient coating 3 (film thickness: of the stacked in regular turn AlN monocrystalline resilient coating 2 with high carbon concentration on Sapphire Substrate 1.On the upper surface of the exposed portions serve of Si doped n type GaN contact layer 5, form the n lateral electrode 18 that constitutes by the resulting composite membrane of deposit Ti/Pt/Au in regular turn.
The second volume minor structure 109 (it will be described hereinafter) as the feature of this modification is formed on the Si doped n type GaN contact layer 5, and by Si doped n type AlGaN limiting layer 10 (the Al composition: 15%, film thickness: 20nm) further form first multi-quantum pit structure 119 (it will be described hereinafter) thereon.
In addition, the same with first embodiment, stacked in regular turn Mg doped p type AlGaN electron barrier layer 13 (Al compositions: 35% on this structure, film thickness: 25nm), Mg doped p type AlGaN contact layer 14 (Al compositions: 2%, 0.2 μ m), high concentration Mg doped p type AlGaN contact layer 15 (Al compositions: 2% film thickness:, film thickness: 10nm), high concentration Si doped n type AlGaN contact layer 16 (Al compositions: 2%, film thickness: 10nm) and the n type AlGaN contact layer 17 of silicon doping (the Al composition: 2%, film thickness: 1 μ m).At the n of silicon doping type Al
0.11Ga
0.89Form the p lateral electrode 19 that constitutes by by the resulting composite membrane of deposit Ti/Pt/Au in regular turn on the upper surface of the part of N contact layer 17.
First and second multi-quantum pit structures as this modification feature will be described now.Between Si doped n type AlGaN limiting layer 10 and electron barrier layer 13, form first multi-quantum pit structure 119, it injects near ultraviolet emission layer 120 by a plurality of electric currents that all have the 370nm wavelength
1With 120
2Constitute.Promptly, AlInGaN first barrier layer (Al composition: 7%, In composition: 0.5%, film thickness: 4nm) 121 be formed on the Si doped n type AlGaN limiting layer 10, and Si doped n type AlInGaN second barrier layer (Al composition: 7%, In composition: 0.5%, film thickness: 4nm) 122, the one InGaN electric current injects near ultraviolet emission layer (In composition: 4%, film thickness: 4nm, wavelength: 370nm) 123, Si doped n type AlInGaN the 3rd barrier layer (Al composition: 7%, In composition: 0.5%, film thickness: 4nm) 124 and AlInGaN the 4th barrier layer (Al composition: 7%, the In composition: 0.5%, film thickness: 4nm) 125 form thereon in regular turn with said sequence.
And, have and the 5th barrier layer 122 of second barrier layer, 122 same structures ' be formed on the 4th barrier layer 125, the 2nd InGaN electric current injects near ultraviolet emission layer (In composition: 4%, film thickness: 4nm, wavelength: 370nm) 123 ' be formed on the 5th barrier layer, and have and the 6th barrier layer 124 of the 3rd barrier layer 124 same structures ' and have and the 7th barrier layer 125 of the 4th barrier layer 125 same structures ' form thereon in regular turn by said sequence.
Although second multi-quantum pit structure 109 is formed between the GaN contact layer 5 and Si doped n type AlGaN limiting layer 10 of Si doping, it forms the optical excitation near ultraviolet emission layer 110 with 380nm wavelength by 25 circulations and obtains.
Optical excitation near ultraviolet emission layer 110 is by Si doped n type AlInGaN the 8th barrier layer (Al composition: 7%, In composition: 0.5%, film thickness: 4nm) 111, InGaN optical excitation near ultraviolet emission layer (In composition: 5%, film thickness: 4nm, wavelength: 380nm) 112 and Si doped n type AlInGaN the 9th barrier layer 113 (Al composition: 7%, the In composition: 0.5%, film thickness: 4nm) constitute.First multi-quantum pit structure 109 repeats stacked this optical excitation near ultraviolet emission layer 110 by 25 circulations and obtains.
As mentioned above, according to first embodiment, can realize to launch ultraviolet light with two kinds of different wave lengths or black light and good luminescent device aspect color rendering.
(second embodiment)
Fig. 4 shows the sectional view according to the structure of the luminescent device of second embodiment of the invention.Identical reference number represents to be equal to the part of those parts among Fig. 1.As shown in this Fig, be by making fluorescent material and the White LED that is obtained according to the light-emitting diodes pipe jointing shown in Fig. 1 of first embodiment according to the luminescent device of present embodiment.That is, as shown in Figure 4, on the inner surface that reflectance coating 32 is arranged on by formed encapsulation 31 such as potteries, and reflectance coating 32 is arranged on the inner surface and lower surface of encapsulation 31 discretely.Reflectance coating 32 is formed by for example aluminium.Light-emitting diode shown in Fig. 1 is installed on the reflectance coating 32 that is arranged on encapsulation 31 the lower surface.
N lateral electrode 18 is connected with the unshowned electrode that is provided with on encapsulation 31 sides with 34 by the jointing metal silk 33 by formation such as billons respectively with p lateral electrode 19.Realize this connection at reflectance coating on the inner surface 32 and the part place between the reflectance coating on the lower surface 32.And, form the fluorescent material district 35 comprise red fluorescent material, covering light-emitting diode or jointing metal silk 33 and 34, and in this fluorescent material district 35, form the fluorescent material district 36 that comprises blueness, green or yellow fluorescent material.The cover 37 that is formed by silicones is arranged in this fluorescent material district 36.
Fluorescent material district 35 comprises resin and the red fluorescent material that is dispersed in this resin.As red fluorescent material, can use for example Y
2O
3Or YVO
4As basic material, and in this material, comprise trivalent Eu (Eu
3+) as activator.That is YVO,
4: Eu
3+, Y
2O
3: Eu
3+Deng can be used as red fluorescent material.Eu
3+Concentration be 1 to 10% according to molar concentration.As the basic material of red fluorescent material, remove Y
2O
3Or YVO
4In addition, can also use LaOS, Y
2(P, V) O
4Deng.Remove Eu
3+In addition, can also use Mn
4+Deng.Especially, because by adding a spot of Bi to YVO with trivalent Eu
4Increased the absorption of 350nm in the basic material, so can further improve the light emission effciency.In addition, as resin, can use silicones etc.
In addition, phosphor layer 36 comprises resin and the blueness, green or the yellow fluorescent material that are dispersed in this resin.Blue fluorescent substance can combine with the green fluorescence material, and perhaps blue fluorescent substance can combine with yellow fluorescent substance, perhaps can be used in combination blue fluorescent substance, green fluorescence material and yellow fluorescent substance.
As blue fluorescent substance, for example, can use (Sr, Ca)
10(PO
4)
6Cl
2: Eu
2+, BaMg
2Al
16O
27: Eu
2+Deng.As the green fluorescence material, can use the Y that for example has as the trivalent Tb of launching centre
2SiO
5: Ce
3+, Tb
3+When with energy during from the Ce ion transfer to the Tb ion, launching efficiency improves.In addition, as the green fluorescence material, can use for example Sr
4Al
14O
25: Eu
2+Deng.As yellow fluorescent substance, can use for example Y
3Al
5: Ce
3+Deng.And, as resin, can use silicones etc.Especially, because trivalent Tb demonstrates strong light emission become the 500nm at maximum place in luminance near, so when the fashionable light emission effciency that significantly improves of strong light emitter junction of itself and trivalent Eu.
Luminescent device according to present embodiment, excite effectively towards the ultraviolet light of the 345nm of p lateral electrode 19 sides emissions to have the fluorescent material that is included in the fluorescent material district 35, and convert the light of narrow Wavelength distribution to about 620nm as the trivalent Eu of launching centre etc.That is to say,, can obtain red visible light effectively by having the short wavelength's who is not more than 350nm ultraviolet light.
In addition, the black light of the 380nm that is produced from Si doped n type GaInN near ultraviolet emission layer 8 is launched to substrate 1 side or p lateral electrode 19 sides, and by utilizing the reflection on reflectance coating 32 can also effectively utilize this light.That is,, excite the blueness, green or the yellow fluorescent substance that in fluorescent material district 36, are comprised effectively by the black light of this 380nm, thus acquisition blueness effectively, green or yellow visible light.
Therefore, except that red visible light, blueness, green or yellow visible light can also be produced effectively, and, white light or any other shades of colour light of splendid color rendering can be obtained to have very effectively as the result who mixes these light.
Manufacture method according to the luminescent device of present embodiment will be described now.The technology of the light-emitting diode shown in the shop drawings 1 is identical with technology in first embodiment.At first, on encapsulation 31 inner surface, form metal film, and this metal film of composition is to stay reflectance coating 32 on each of the inner surface of encapsulation 31 and lower surface as reflectance coating by sputtering method.Then, the light-emitting diode that will make in first embodiment (corresponding to 1 among Fig. 4,30,18 and 19) is mounted and fixed on the reflectance coating 32 on encapsulation 31 the lower surface.For this is fixed, can adopt the joint that utilizes binding agent, welding etc.
Then, by jointing metal silk 33 and 34, n lateral electrode 18 and p lateral electrode 19 are connected respectively with the unshowned electrode that is provided with on encapsulation 31 sides.In addition, form the fluorescent material district 35 comprise red fluorescent material, covering light-emitting diode or jointing metal silk 33 and 34, and in this fluorescent material district 35, form the fluorescent material district 36 that comprises blueness, green or yellow fluorescent material.As each formation method in fluorescent material district 35 and 36, drippage wherein is dispersed with the mixture of every kind of fluorescent material in the resinogen material blends, and heat-treats to realize thermal polymerization, makes hardening of resin.It should be noted that drippage and keep comprise every kind of fluorescent material resinogen material compound liquid a little while, harden then.As a result, the fine granular of every kind of fluorescent material deposition makes the fine granular of every kind of fluorescent material can be confined in the lower layer of each fluorescent material district 35 and 36, thereby suitably controls the luminous efficiency of every kind of fluorescent material.Then, cover 37 is set in fluorescent material district 36, thereby produces White LED according to present embodiment.
(the 3rd embodiment)
Fig. 5 shows the sectional view according to the structure of the luminescent device of third embodiment of the invention.Identical reference number represents to be equal to the part of those parts in Fig. 1 and 4.As shown in Figure 5, the luminescent device according to present embodiment also is by making fluorescent material and the White LED that is obtained according to the light-emitting diodes pipe jointing shown in Fig. 1 of first embodiment.Also be arranged at the below of light-emitting diode with the different fluorescent material districts that are of second embodiment.
As shown in Figure 5, on the reflectance coating 32 on encapsulation 31 the lower surface, form the fluorescent material district 41 that comprises blueness, green or yellow fluorescent substance, and in this fluorescent material district 41, install and the fixing light-emitting diode shown in Fig. 1.The joint of employing adhesive, welding etc. can be used to fix this light-emitting diode.By jointing metal silk 33 and 34, n lateral electrode 18 and p lateral electrode 19 respectively be arranged at encapsulation 31 sides on unshowned electrode be connected. Jointing metal silk 33 and 34 is set to pierce through fluorescent material district 41 respectively.The same with second embodiment, the part place between the reflectance coating on reflectance coating on the inner surface 32 and the lower surface 32 realizes this connection.Formation comprises the fluorescent material district 42 of red fluorescent material, covering light-emitting diode or jointing metal silk 33 and 34, and forms the fluorescent material district 43 that comprises blueness, green or yellow fluorescent material in this fluorescent material district 42.
According to the White LED of present embodiment,, also demonstrate following effect except that the resulting effect in a second embodiment.Just, owing to below light-emitting diode, also be provided with fluorescent material district 41, so the light of launching towards substrate 1 side of the 380nm black light that is produced also enters fluorescent material district 41, therefore can excite the fluorescent material in this fluorescent material district 41 in the Si of light-emitting diode doped n type GaInN optical excitation near ultraviolet emission layer 8.Therefore, not only the fluorescent material in the optical excitation fluorescent material district 43 reflected of reflectance coating 32 come luminous, but and the fluorescent material in the fluorescence excitation material district 41 come luminous.Therefore, can further improve the light emission effciency.In addition, owing to main this fluorescent material district 41 of black light irradiation with 380nm launches the light with other color except that red, thus can adjust colour temperature independently, thus color rendering further improved.
(the 4th embodiment)
Fig. 6 shows the sectional view according to the structure of the luminescent device of fourth embodiment of the invention.Identical reference number represents to be equal to the part of those parts among Fig. 1.As shown in this Fig, be the light-emitting diode that constitutes by formed GaN based compound semiconductor on Sapphire Substrate according to the luminescent device of present embodiment.With the difference of the light-emitting diode shown in Fig. 1 be the structure of GaN absorbed layer and GaInN optical excitation near ultraviolet emission layer.
As shown in Figure 6, by stacked Si doped n type GaN first absorbed layer 51 (the Si concentration: 1 * 10 in regular turn
18/ cm
3, film thickness: 50nm), the Si doped n type GaInN first optical excitation near ultraviolet emission layer 52 (Si concentration: 1 * 10
18/ cm
3, film thickness: 3nm, wavelength: 380nm), Si doped n type GaN second absorbed layer 53 (the Si concentration: 1 * 10
18/ cm
3, film thickness: 100nm), the Si doped n type GaInN second optical excitation near ultraviolet emission layer 54 (Si concentration: 1 * 10
18/ cm
3, film thickness: 3nm, wavelength: 380nm) and Si doped n type GaN the 3rd absorbed layer 55 (Si concentration: 1 * 10
18/ cm
3, film thickness: 50nm), structure is according to the GaN absorbed layer and the GaInN optical excitation near ultraviolet emission layer of the light-emitting diode of present embodiment.
According to the light-emitting diode of present embodiment, can obtain the effect identical with the effect of first embodiment, and the same with the second and the 3rd embodiment, can construct White LED by this light-emitting diode is combined with fluorescent material.In addition, in the stepped construction of GaN absorbed layer and GaInN optical excitation near ultraviolet emission layer, the increase of the quantity of stacked absorbed layer and optical excitation emission layer can reduce the film thickness of every tunic, keeps injecting from electric current the absorption efficiency of the light of ultraviolet emission layer emission simultaneously.Therefore, can reduce defect influence, the light-emitting diode with splendid reliability and efficient is provided thus.
It should be noted that in the present embodiment Mg doped p type Al
0.11Ga
0.89 N contact layer 14 directly contacts the n type Al of silicon doping
0.11Ga
0.89 N contact layer 17, and high concentration Mg doped p type Al
0.11Ga
0.89N contact layer 15 and high concentration Si doped n type Al
0.11Ga
0.89N contact layer 16 is not inserted between these layers.Owing to can reduce resistance effectively, are desirable structures so wherein there is the structure of these contact layers 15 and 16.Yet,, can cancel contact layer 15 and 16 by as concentration according to the desired increase contact layer 14 of required resistance value and 17.
(the 5th embodiment)
Fig. 7 shows the sectional view according to the structure of the luminescent device of fifth embodiment of the invention.Identical reference number represents to be equal to the part of those parts among Fig. 1.As shown in this Fig, be the light-emitting diode that constitutes by formed GaN based compound semiconductor on Sapphire Substrate according to the luminescent device of present embodiment.Be on the back side of Sapphire Substrate, to be provided with the reflector with the difference of the light-emitting diode shown in Fig. 1.
As shown in Figure 7, in according to the light-emitting diode in the present embodiment, on the back side of Sapphire Substrate 1, form reflectance coating 61.This reflectance coating 61 is formed by for example aluminium, silver, nickel etc.Implement light-emitting diode by this way, so that reflectance coating 61 is positioned on the base section of encapsulation.Can reflectance coating 61 be fixed in the encapsulation 31 by adopting adhesive bond, welding etc.
According to the light-emitting diode of present embodiment, can obtain the effect identical with the effect of first embodiment, and the same with the second and the 3rd embodiment, can construct White LED by this light-emitting diode is combined with fluorescent material.And in fact reflectance coating 61 is used as the reflectance coating 32 among second embodiment, thereby is convenient to implement as LED.
It should be noted that reflectance coating 61 can be fixed on the lower surface of encapsulation 31 of the reflectance coating 32 that has between it among second embodiment.In this case, can use welding to wait is used for fixing.
(the 6th embodiment)
Fig. 8 shows the sectional view according to the structure of the luminescent device of sixth embodiment of the invention.As shown in this Fig, be the light-emitting diode that constitutes by formed GaN based compound semiconductor on the GaN substrate according to the luminescent device of present embodiment.
As shown in Figure 8, in Si doped n type low resistance GaN substrate 71 (the Si concentration: 3 * 10 that have by the formed surface of c face of band Ga polarity
18/ cm
3, film thickness: 100 μ m), stacked in regular turn Si doped n type Al
0.05Ga
0.95N first limiting layer 72 (the Si concentration: 1 * 10
18/ cm
3, film thickness: 20nm), Si doped n type GaN first absorbed layer 73 (the Si concentration: 1 * 10
18/ cm
3, film thickness: 100nm), Si doped n type GaInN optical excitation blue light emission layer 74 (Si concentration: 6 * 10
18/ cm
3, film thickness: 2nm, wavelength: 440nm), Si doped n type GaN second absorbed layer 75 (the Si concentration: 1 * 10
18/ cm
3, film thickness: 100nm), Si doped n type Al
0.11Ga
0.89N second limiting layer 76 (the Si concentration: 1 * 10
18/ cm
3, film thickness: 20nm), Si doped n type Al
0.06Ga
0.94N ultraviolet emission layer 77 (Si concentration: 1 * 10
18/ cm
3, film thickness: 3nm, wavelength: 345nm), the Al of non-doping
0.11Ga
0.89N wall 78 (film thickness: 20nm), Mg doped p type Al
0.28Ga
0.72N electron barrier layer 79 (Mg concentration: 1 * 10
19/ cm
3, film thickness: 100nm), Mg doped p type Al
0.11Ga
0.89N contact layer 80 (Mg concentration: 1 * 10
19/ cm
3, film thickness: 100nm), high concentration Mg doped p type Al
0.11Ga
0.89N contact layer 81 (Mg concentration: 2 * 10
20/ cm
3, film thickness: 20nm), high concentration Si doped n type Al
0.11Ga
0.89N contact layer 82 (Si concentration: 1 * 10
20/ cm
3, film thickness: 20nm) with Si doped n type Al
0.11Ga
0.89N contact layer 83 (Si concentration: 5 * 10
18/ cm
3, film thickness: 100nm).Identical with first embodiment, p type Al
0.11Ga
0.89N contact layer 81 and n type Al
0.11Ga
0.89N contact layer 82 is the layers that reduce resistance.
On the back side of n type low resistance GaN substrate 71, form by passing through the n lateral electrode 84 of the resulting composite membrane formation of deposit Ti (0.05 μ m)/Pt (0.05 μ m)/Au (1.0 μ m) in regular turn.Similarly, at Si doped n type Al
0.11Ga
0.89Form on the upper surface of the part of N contact layer 83 by passing through the p lateral electrode 85 of the resulting composite membrane formation of deposit Ti (0.05 μ tm)/Pt (0.05 μ m)/Au (1.0 μ m) in regular turn.
In the light-emitting diode according to present embodiment, identical with first embodiment, electronics is from n type Al
0.11Ga
0.89N second limiting layer 76 is injected into Al
0.06Ga
0.94In the N ultraviolet emission layer 77, the hole is from Mg doped p type Al
0.28Ga
0.72N electron barrier layer 79 passes Al
0.11Ga
0.89N wall 78 is injected into in one deck, and from Al
0.06Ga
0.9477 emission of N ultraviolet emission layer have the ultraviolet light of 345nm wavelength.Ultraviolet light transmission towards the emission of p lateral electrode 85 sides is passed from Al
0.11Ga
0.89N wall 78 to Si doped n type Al
0.11Ga
0.89Each layer of N contact layer 83, and emission to the outside effectively.This be because these layers in each layer energy gap greater than with the emission the corresponding energy of ultraviolet light wavelength.
On the other hand, ultraviolet light towards the emission of substrate 71 sides is absorbed in Si doped n type GaN second absorbed layer 75 and Si doped n type GaN first absorbed layer 73, and electronics that is produced and hole are compound in Si doped n type GaInN optical excitation blue light emission layer 74, thus the blue light of emission 440nm.Because the energy of this light is less than the energy gap of GaN,, and in these substrate 71 grades, be not absorbed so it is launched to the outside from n type low resistance GaN substrate 71 effectively.This light also towards the emission of p lateral electrode 85 sides, pass from Si doped n type GaN second absorbed layer 75 to n type Al by transmission
0.11Ga
0.89 N contact layer 83 each the layer and be not absorbed, and be transmitted into effectively the outside.
Total film thickness as n type GaN first absorbed layer 73 and n type GaN second absorbed layer 75, in view of absorption efficiency with excite the compromise of carrier loss, 0.1 to 0.5 μ m be suitable, and identical with first embodiment, wherein the structure of absorption portion and luminous component separation can reduce the film thickness of GaInN light-emitting layer.When reducing film thickness by this way, can alleviate the influence of the piezoelectric field that causes by strain, and because the reduction of the carrier mobility that alloy scattering causes becomes significantly, this has reduced defective and has captured speed.Thereby can suppress to launch compound by the non-light that crystal defect causes.Therefore, can obtain high light emission effciency.
As mentioned above, light-emitting diode according to present embodiment, ultraviolet light with the short wavelength who is not more than 350nm can outwards be launched effectively, and can excite the red fluorescent material of being mentioned in conjunction with first embodiment effectively, thereby improves the light emission effciency of red visible light.In addition, be transmitted in the blue light of the 440nm that is produced in the Si doped n type GaInN optical excitation blue light emission layer 74 towards substrate 71 sides or p lateral electrode 85 sides, and also can effectively utilize this light.For example, can utilize this light to excite the fluorescent material that produces visible light, thereby obtain to have the visible light of the color except that red effectively with the color except that red light.Combine by making, can obtain white light or have any other versicolor light according to the luminescent device of present embodiment and red fluorescent material or fluorescent material with any other color.
In addition, have conductive of n-type low resistance GaN substrate 71 as substrate, form technology so can be convenient to electrode, and the installation in encapsulation also becomes easy owing to use.And, the n lateral electrode 84 that is provided with on the back side of n type low resistance GaN substrate 71 also is used for being reflected in the blue light of the 440nm that Si doped n type GaInN optical excitation blue light emission layer 74 produced, thereby can effectively utilize this blue light, and can be reduced at the technology that forms reflectance coating on the inner surface of encapsulation.
As the manufacturing method for LED of present embodiment, can use method in conjunction with first embodiment explanation.Just, make the GaN substrate of making by the thick film growth that utilizes hydride gas-phase epitaxy as n type low resistance GaN substrate 71, and identical with first embodiment, and the component structure part of growth light-emitting diode is (from n type Al on this GaN substrate
0.05Ga
0.95N first limiting layer 72 to n type Al
0.11Ga
0.89Each layer of N contact layer 83).As the manufacture method of the GaN substrate that utilizes hydride gas-phase epitaxy, can use gallium chloride and ammonia the method for having utilized as source gas, with under atmospheric pressure and about 1000 ℃ condition, the film that carries out the GaN layer on the substrate that is made of sapphire etc. forms.
(the 7th embodiment)
Fig. 9 shows the sectional view according to the structure of the luminescent device of seventh embodiment of the invention.Identical reference number represents to be equal to the part of those parts among Fig. 4.As shown in this Fig, be to combine the White LED that is obtained with fluorescent material by making according to the light-emitting diode shown in Fig. 8 of the 6th embodiment according to the luminescent device of present embodiment.That is, as shown in Figure 9, on the inner surface of encapsulation 31, reflectance coating 32 is set, and the light-emitting diode shown in Fig. 7 is installed on the lower surface of encapsulation 31 in the mode of its n lateral electrode 84 in the face of this lower surface.Reference number 90 expression element structure divisions.
Luminescent device according to present embodiment, excite effectively towards the ultraviolet light of the 345nm of p lateral electrode 85 sides emissions to have the fluorescent material that is included in the phosphor layer 87, and convert light to near the narrow Wavelength distribution 620nm as the trivalent Eu of launching centre etc.That is to say that the ultraviolet light with the short wavelength who is not more than 350nm can obtain red visible light effectively.
In addition, the blue light of the 440nm that is produced in Si doped n type GaInN optical excitation blue-light emitting layer 74 is towards substrate 71 sides or the emission of p lateral electrode 85 sides.By utilizing the reflection on the n lateral electrode 84, can also effectively utilize this light.That is, the blue light of this 440nm can excite the fluorescent material with green or yellow that is comprised effectively in phosphor layer 88, thereby obtains to have green or yellow visible light effectively.
Therefore, can produce the blue light of red visible light, 440nm effectively and have green or yellow visible light, and, can obtain to have white light or any other versicolor light of splendid color rendering effectively as the result who mixes these light.
(the 8th embodiment)
Figure 10 shows the sectional view according to the structure of the luminescent device of eighth embodiment of the invention.Identical reference number represents to be equal to the part of those parts among Fig. 1.As shown in this Fig, be the light-emitting diode that constitutes by formed GaN based compound semiconductor on Sapphire Substrate according to the luminescent device of present embodiment.Be that with the difference of the light-emitting diode shown in Fig. 1 electric current injects between ultraviolet emission layer and the optical excitation near ultraviolet emission layer and is provided with the contact layer that it is provided with the n lateral electrode.
As shown in Figure 10, in luminescent device according to present embodiment, on the GaN of non-doping resilient coating 4, stacked in regular turn Al
0.05Ga
0.95N first limiting layer 91 (film thickness: 20nm), GaN first absorbed layer 92 (film thickness: 50nm), the Si doped n type GaInN first optical excitation near ultraviolet emission layer 93 (Si concentration: 1 * 10
18/ cm
3, film thickness: 3nm, wavelength: 380nm), GaN second absorbed layer 94 (film thickness: 100nm), the Si doped n type GaInN second optical excitation near ultraviolet emission layer 95 (Si concentration: 1 * 10
18/ cm
3, film thickness: 3nm, wavelength: 380nm), GaN the 3rd absorbed layer 96 (film thickness: 50nm), Al
0.11Ga
0.89N first limiting layer 97 (film thickness: 20nm), Si doped n type Al
0.10Ga
0.90N contact layer 98 (Si concentration: 5 * 10
18/ cm
31.5 μ m) and the Al of non-doping, film thickness:
0.11Ga
0.89N wall 99 (film thicknesses: 20nm).
In addition, at Al
0.11Ga
0.89On the N wall 99, stacked in regular turn Si doped n type Al
0.06Ga
0.94The N electric current injects ultraviolet emission layer 11, Al
0.11Ga
0.89N wall 12, Mg doped p type Al
0.28Ga
0.72N electron barrier layer 13, Mg doped p type Al
0.11Ga
0.89 N contact layer 14 and Si doped n type Al
0.11Ga
0.89N contact layer 17.In addition, at Si doped n type Al
0.10Ga
0.90N lateral electrode 100 is set on the N contact layer 98.
It should be noted that in the present embodiment Mg doped p type Al
0.11Ga
0.89 N contact layer 14 directly contacts Si doped n type Al
0.11Ga
0.89 N contact layer 17, and high concentration Mg doped p type Al
0.11Ga
0.89N contact layer 15 and high concentration Si doped n type Al
0.11Ga
0.89N contact layer 16 is not inserted between these layers.Although owing to can reduce resistance effectively, wish wherein these contact layers 15 and 16 structures that exist,, can cancel contact layer 15 and 16 by as concentration according to the desired increase contact layer 14 of required resistance value and 17.
In the light-emitting diode according to present embodiment, electronics is from Si doped n type Al
0.10Ga
0.90 N contact layer 98 passes Al
0.11Ga
0.89N wall 99 is injected into Al
0.06Ga
0.94The N electric current injects ultraviolet emission layer 11, and the hole is from Mg doped p type Al
0.28Ga
0.72N electron barrier layer 13 passes Al
0.11Ga
0.89N wall 12 is injected into in one deck, and the same with first embodiment, from Al
0.06Ga
0.94The N electric current injects the ultraviolet light that 11 emission of ultraviolet emission layer have the 345nm wavelength.Ultraviolet light transmission towards the emission of p lateral electrode 19 sides is passed from Al
0.11Ga
0.89N wall 12 to Si doped n type Al
0.11Ga
0.89Each layer of N contact layer 17, and be transmitted into the outside effectively.
On the other hand, ultraviolet light towards the emission of substrate 1 side is absorbed in Si doped n type GaN the 3rd absorbed layer 96, Si doped n type GaN second absorbed layer 94 and Si doped n type GaN first absorbed layer 92, and electronics that is produced and hole are compound in Si doped n type GaInN second optical excitation near ultraviolet emission layer 95 and the Si doped n type GaInN first optical excitation near ultraviolet emission layer 93, thus the light of emission 380nm.Because the energy of this light is less than the energy gap of GaN,, and in the GaN of non-doping resilient coating 4 grades, be not absorbed so it is launched to the outside from substrate 1 effectively.This light also towards the emission of p lateral electrode 19 sides, pass from Si doped n type GaN second absorbed layer 94 to n type Al by transmission
0.11Ga
0.89 N contact layer 17 each the layer and be not absorbed, and be transmitted into effectively the outside.
As mentioned above, according to the light-emitting diode of present embodiment, can obtain the effect identical, and can demonstrate following effect with the effect of first embodiment.Just, since electronics from Si doped n type Al
0.10Ga
0.90 N contact layer 98 passes Al
0.11Ga
0.89N wall 99 is injected into Al
0.06Ga
0.94The N electric current injects ultraviolet emission layer 11, and electric current needn't flow through and be positioned at Si doped n type Al
0.11Ga
0.89Each layer of N first limiting layer 97 belows.Therefore, needn't these the layer in doping Si so that n type layer to be provided.The Si that do not mix in GaN second absorbed layer 92,94 or 96, even perhaps be doped with Si, doping is also very little.As a result, can prevent from absorbed layer 92,94 or 96, to produce the light that has corresponding to the wavelength of GaN energy gap.When generation has light time corresponding to the wavelength of GaN energy gap, it is absorbed in the GaN of aforesaid non-doping resilient coating 4 grades, has reduced efficient thus.On this basis, can produce light effectively from Si doped n type GaInN second optical excitation near ultraviolet emission layer 95 and the Si doped n type GaInN first optical excitation near ultraviolet emission layer 93 with 380nm wavelength.
(the 9th embodiment)
Figure 11 shows the sectional view according to the structure of the luminescent device of ninth embodiment of the invention.Identical reference number represents to be equal to the part of those parts in Fig. 1 and 10.As shown in this Fig, be the light-emitting diode that constitutes by formed GaN based compound semiconductor on Sapphire Substrate according to the luminescent device of present embodiment.Be that with the difference of the light-emitting diode shown in Fig. 1 electric current injects between ultraviolet emission layer and the optical excitation near ultraviolet emission layer and is provided with the contact layer that it is provided with the n lateral electrode in addition.
As shown in Figure 11, in luminescent device according to present embodiment, on Si doped n type GaN contact layer 5, stacked in regular turn Si doped n type Al
0.05Ga
0.95N first limiting layer 101 (the Si concentration: 1 * 10
18/ cm
3, film thickness: 20nm), Si doped n type GaN first absorbed layer 102 (the Si concentration: 1 * 10
18/ cm
3, film thickness: 50nm), the Si doped n type GaInN first optical excitation near ultraviolet emission layer 103 (Si concentration: 1 * 10
18/ cm
3, film thickness: 3nm, wavelength: 380nm), Si doped n type GaN second absorbed layer 104 (the Si concentration: 1 * 10
18/ cm
3, film thickness: 100nm), the Si doped n type GaInN second optical excitation near ultraviolet emission layer 105 (Si concentration: 1 * 10
18/ cm
3, film thickness: 3nm, wavelength: 380nm), Si doped n type GaN the 3rd absorbed layer 106 (Si concentration: 1 * 10
18/ cm
3, film thickness: 50nm) and Si doped n type Al
0.11Ga
0.89N second limiting layer 107 (the Si concentration: 1 * 10
18/ cm
3, film thickness: 20nm).At n type Al
0.11Ga
0.89On N second limiting layer 107, stacked in regular turn identical with the 8th embodiment from Si doped n type Al
0.10Ga
0.90N contact layer 98 to Si doped n type Al
0.11Ga
0.89Each layer of N contact layer 17.
In addition, on Si doped n type GaN contact layer 5, n lateral electrode 108 is set, and this electrode, at Si doped n type Al
0.10Ga
0.90Target 100 on the N contact layer 98 and at n type Al
0.11Ga
0.89 P lateral electrode 19 on the N contact layer 17 forms three-end electrode.When to when the part between p lateral electrode 19 and the target 100 and the part between n lateral electrode 108 and target 100 apply voltage, can be with electric current supply to Al
0.06Ga
0.94The N electric current injects ultraviolet emission layer 11, the Si doped n type GaInN second optical excitation near ultraviolet emission layer 105 and the Si doped n type GaInN first optical excitation near ultraviolet emission layer 103.
In light-emitting diode according to present embodiment, identical with the 8th embodiment, from Al
0.06Ga
0.94The ultraviolet light that 11 emission of N ultraviolet emission layer have the 345nm wavelength passes from Al towards the ultraviolet light transmission of p lateral electrode 19 sides emission
0.11Ga
0.89N wall 12 to Si doped n type Al
0.11Ga
0.89Each layer of N contact layer 17, and be transmitted into the outside effectively.
On the other hand, ultraviolet light towards the emission of substrate 1 side is absorbed in Si doped n type GaN the 3rd absorbed layer 106, Si doped n type GaN second absorbed layer 104 and Si doped n type GaN first absorbed layer 102, and electronics that is produced and hole are compound in Si doped n type GaInN second optical excitation near ultraviolet emission layer 105 and the Si doped n type GaInN first optical excitation near ultraviolet emission layer 103, thus the light of emission 380nm.Because the energy of this light is less than the energy gap of GaN,, and in the GaN of non-doping resilient coating 4, Si doped n type GaN contact layer 5 etc., be not absorbed so it is launched to the outside from substrate 1 effectively.This light also towards the emission of p lateral electrode 19 sides, pass from Si doped n type GaN second absorbed layer 104 to n type Al effectively by transmission
0.11Ga
0.89 N contact layer 17 each the layer and be not absorbed, and be transmitted into effectively the outside.
As mentioned above, according to the light-emitting diode of present embodiment, can obtain the effect identical, and can demonstrate following effect with the effect of first embodiment.Just because not to applying electric field according to the optical excitation near ultraviolet emission layer in the structure of present embodiment, so that electronics is inoperative with the power that the hole separates, can expect high efficiency thus.
It should be noted that and the invention is not restricted to the foregoing description.For example, form the fluorescent material district that comprises red fluorescent material in the above-described embodiments discretely and comprised the fluorescent material district of blueness, green or yellow fluorescent substance, but the fluorescent material district that can utilize red fluorescent material wherein and blue, green or yellow fluorescent substance to mix.In this case, can reduce the quantity in fluorescent material district, thereby simplify manufacturing step.In addition, the fluorescent material that is selected from blueness, green and yellow fluorescent substance can mix with red fluorescent material constituting a phosphor layer, and can stacked this phosphor layer and comprise the fluorescent material district of another fluorescent material that is selected from blueness, green and yellow fluorescent substance.
In addition, as transparent substrates, the substrate that can utilize Sapphire Substrate, GaN substrate, SiC substrate or form by any other material.In addition, Multiple Quantum Well can be used for light-emitting layer, and perhaps modulation doping can be used for the doping impurity part.
Industrial applicibility
According to the present invention and since light emitting diode and fluorescent material can be used for providing have splendid efficient and The luminescent device of color rendering is so can replace in conventional white fluorescent lamp field of using Generation.
Claims (25)
1. luminescent device comprises:
Transparent substrates, it has first surface and second surface;
Semiconductor layer, it is arranged on the described first surface of described transparent substrates;
First light-emitting layer, it is arranged on the described semiconductor layer, and emission comprises and first ultraviolet light greater than the corresponding wavelength of the energy of the semi-conductive energy gap of described semiconductor layer;
Second light-emitting layer, it is arranged between described first light-emitting layer and the described semiconductor layer, absorption is from described first ultraviolet light of described first light-emitting layer emission, and emission comprises and second ultraviolet light less than the corresponding wavelength of the energy of the semi-conductive energy gap of described semiconductor layer; And
First electrode and second electrode, it is for applying electric power setting to described first light-emitting layer.
2. according to the luminescent device of claim 1, also comprise the fluorescent material member, its comprise by described first ultraviolet excitation have with emission first wavelength light first fluorescent material and have second fluorescent material of the light of second wavelength with emission by described second ultraviolet excitation.
3. according to the luminescent device of claim 2, wherein said fluorescent material member comprises the first fluorescent material district and the second fluorescent material district, the described first fluorescent material district comprises described first fluorescent material that emission has the light of described first wavelength, and the described second fluorescent material district comprises described second fluorescent material.
4. according to the luminescent device of claim 2, described second wavelength of wherein said first wavelength ratio is long.
5. according to the luminescent device of claim 3, the wherein said first fluorescent material district is arranged on the described first light-emitting layer side opposite with described transparent substrates at least, and the described second fluorescent material district is arranged on the described second light-emitting layer side opposite with described first light-emitting layer at least.
6. according to the luminescent device of claim 5, described second wavelength of wherein said first wavelength ratio is long.
7. according to the luminescent device of claim 2, wherein said first fluorescent material is to have the red fluorescent material of trivalent Eu as launching centre.
8. according to the luminescent device of claim 1, also comprise the reflector on the described second surface that is arranged on described transparent substrates.
9. according to the luminescent device of claim 1, wherein said first light-emitting layer comprises AlGaN.
10. according to the luminescent device of claim 1, also comprise first contact layer, its energy gap is wider than the energy gap of described first light-emitting layer, and it is arranged on described first light-emitting layer top, and wherein said first electrode is arranged on described first contact layer.
11. according to the luminescent device of claim 10, wherein said first light-emitting layer comprises AlGaN, and described first contact layer comprises the n type AlGaN layer of its Al composition greater than the Al composition of described first light-emitting layer.
12. according to the luminescent device of claim 11, also comprise p type AlGaN layer, it is arranged between described first light-emitting layer, and its Al composition is greater than the Al composition of described first light-emitting layer.
13. luminescent device according to claim 12, also comprise high concentration p type AlGaN layer and high concentration n type AlGaN layer, described high concentration p type AlGaN layer is arranged between described p type AlGaN layer and described first contact layer and comprises that its concentration is higher than the p type impurity of the concentration of described p type AlGaN layer, and described high concentration n type AlGaN layer is arranged between described high concentration p type AlGaN layer and described first contact layer and comprises that its concentration is higher than the n type impurity of the concentration of described AlGaN layer.
14. luminescent device according to claim 1, also comprise absorbed layer, it nestles up the described second light-emitting layer setting, and the energy gap of wherein said absorbed layer is wider than the energy gap of described second light-emitting layer and is narrower than the energy gap of described first light-emitting layer, and absorbs described first ultraviolet light.
15. according to the luminescent device of claim 14, wherein said first light-emitting layer comprises AlGaN, and described second light-emitting layer comprises GaInN.
16. according to the luminescent device of claim 1, wherein said first electrode and described second light-emitting layer of described second electrode pair apply electric power.
17. according to the luminescent device of claim 10, also comprise second contact layer, it is arranged on the described second light-emitting layer side opposite with described first light-emitting layer, wherein said second electrode is arranged on described second contact layer.
18. luminescent device according to claim 10, also comprise the 3rd contact layer, its energy gap is wider than the energy gap of described first light-emitting layer, and it is arranged between described first light-emitting layer and described second light-emitting layer, and wherein said second electrode is arranged on described the 3rd contact layer.
19. according to the luminescent device of claim 18, wherein said first light-emitting layer comprises AlGaN, and described the 3rd contact layer comprises the n type AlGaN layer of its Al composition greater than the Al composition of described first light-emitting layer.
20. luminescent device according to claim 18, also comprise the 4th contact layer and third electrode, described the 4th contact layer is arranged on the described second light-emitting layer side opposite with described first light-emitting layer, described third electrode is arranged on described the 4th contact layer, and wherein said third electrode applies electric power to described second light-emitting layer.
21. according to the luminescent device of claim 1, wherein said second ultraviolet light sees through described transparent substrates.
22. according to the luminescent device of claim 1, wherein said transparent substrates is a Sapphire Substrate.
23. according to the luminescent device of claim 1, wherein said semiconductor layer is the GaN layer.
24. according to the luminescent device of claim 23, wherein said transparent substrates is a Sapphire Substrate, and described GaN layer is formed on the described Sapphire Substrate that has the single crystal AlN layer between it.
25., wherein be formed with the AlN layer that its concentration of carbon is higher than the concentration of carbon in described single crystal AlN layer between described single crystal AlN layer and the described Sapphire Substrate according to the luminescent device of claim 24.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005071447 | 2005-03-14 | ||
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103236395A (en) * | 2011-05-25 | 2013-08-07 | 新加坡科技研究局 | Method of forming nanostructures on a substrate and use of the same |
| CN103305917A (en) * | 2012-03-08 | 2013-09-18 | 日立电线株式会社 | Method for manufacturing GaN template substrate and GaN template substrate |
| CN105122475A (en) * | 2013-03-14 | 2015-12-02 | 国家科学研究中心 | Monolithic light-emitting device |
| CN110323295A (en) * | 2019-07-10 | 2019-10-11 | 陕西科技大学 | A kind of multiple quantum wells InGaN solar battery being inserted into AlGaN structure |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9812602B2 (en) | 2012-12-20 | 2017-11-07 | Seoul Viosys Co., Ltd. | Light detection device |
| CN106158803B (en) * | 2012-12-27 | 2019-04-16 | 首尔伟傲世有限公司 | Light detection encapsulation and the portable equipment including light detection encapsulation |
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2006
- 2006-03-07 CN CNB2006800001116A patent/CN100470864C/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103236395A (en) * | 2011-05-25 | 2013-08-07 | 新加坡科技研究局 | Method of forming nanostructures on a substrate and use of the same |
| CN103236395B (en) * | 2011-05-25 | 2016-09-28 | 新加坡科技研究局 | Method forming nanostructured and application thereof in substrate |
| CN103305917A (en) * | 2012-03-08 | 2013-09-18 | 日立电线株式会社 | Method for manufacturing GaN template substrate and GaN template substrate |
| CN105122475A (en) * | 2013-03-14 | 2015-12-02 | 国家科学研究中心 | Monolithic light-emitting device |
| CN105122475B (en) * | 2013-03-14 | 2018-03-02 | 国家科学研究中心 | Monolithic ceramic luminescence device |
| CN110323295A (en) * | 2019-07-10 | 2019-10-11 | 陕西科技大学 | A kind of multiple quantum wells InGaN solar battery being inserted into AlGaN structure |
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| CN100470864C (en) | 2009-03-18 |
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