TW201717427A - Light-emitting element - Google Patents

Abstract

A light-emitting element includes a light-emitting stacked layer including an active layer; and a non-oxide insulating layer under the light-emitting stacked layer, wherein the refraction index of the non-oxide insulating layer is less than 1.4.

Description

Light-emitting element

The present invention relates to a light-emitting element, and more particularly to a light-emitting element having high reflectance.

Photoelectric elements, such as light-emitting diodes (LEDs), have been widely used in optical display devices, traffic signs, data storage devices, communication devices, lighting devices, and medical devices. In addition, the LEDs described above can be combined with other components to form a light emitting device. 1 is a schematic view showing the structure of a conventional light-emitting device. As shown in FIG. 1, a light-emitting device 1 includes a secondary carrier 12 having a circuit 14; a solder 16 is disposed on the secondary carrier 12, whereby the LED is used by the solder 16 11 is fixed on the secondary carrier 12 and electrically connects the LED 11 to the circuit 14 on the secondary carrier 12; and an electrical connection structure 18 for electrically connecting the electrode 15 of the LED 11 with the circuit 14 on the secondary carrier 12; The secondary carrier 12 described above may be a lead frame or a large-sized mosaic substrate.

A light-emitting element comprises a light-emitting layer comprising an active layer; a window layer is disposed on the light-emitting layer; an insulating layer comprises a plurality of holes connected to the window layer; and a conductive substrate is located under the insulating layer The plurality of apertures are electrically connected to the window layer; a first electrode is connected to the light emitting layer; a second electrode is connected to the conductive substrate; wherein the first electrode comprises a current injection portion and an extension portion, and the current The injection portion and the extension have the same thickness in the stacking direction of the light-emitting laminate.

The embodiments of the present invention will be described in detail, and in the drawings, the same or the like

2A is a top view of a light-emitting element according to an embodiment of the present application, and FIG. 2B is a cross-sectional view taken along line AA' of FIG. 2A. As shown in FIG. 2B, a light-emitting element 2 has a substrate 20; a conductive adhesive layer 21 on the substrate 20; a reflective structure 22 on the conductive adhesive layer 20; and a transparent conductive structure 23 on the reflective structure. Above the 22; a window layer 29, located above the transparent conductive structure 23; a non-oxide insulating layer 24, between the transparent conductive structure 23 and the window layer 29; a light-emitting layer 25, located above the window layer 29; An electrical contact layer 26 is disposed over the light emitting stack 25, a first electrode 27 is disposed over the light emitting layer 25 and the electrical contact layer 26, and a second electrode 28 is disposed beneath the substrate 20. The light emitting laminate 25 has a first semiconductor layer 251 between the window layer 29 and the first electrode 27, an active layer 252 between the first semiconductor layer 251 and the first electrode 27, and a second semiconductor layer 253. Located between the active layer 252 and the first electrode 27.

The first electrode 27 and/or the second electrode 28 are for receiving an external voltage and may be composed of a transparent conductive material or a metal material. Transparent conductive materials include, but are not limited to, indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO), zinc tin oxide. (ZTO), gallium zinc oxide (GZO), indium tungsten oxide (IWO), zinc oxide (ZnO), aluminum gallium arsenide (AlGaAs), gallium nitride (GaN), gallium phosphide (GaP), gallium arsenide ( GaAs), phosphorus gallium arsenide (GaAsP), indium zinc oxide (IZO) or diamond-like carbon film (DLC). Metal materials include, but are not limited to, aluminum (Al), chromium (Cr), copper (Cu), tin (Sn), gold (Au), nickel (Ni), titanium (Ti), platinum (Pt), lead (Pb) , zinc (Zn), cadmium (Cd), antimony (Sb), cobalt (Co) or an alloy of the above materials. The first electrode 27 has a current injection portion 271 and an extension portion 272. As shown in FIG. 2A, the current injection portion 271 is located substantially above the center of the second semiconductor layer 253. The extension portion 272 has a first branch line 2721 extending from the current injection portion 271 to the boundary of the light-emitting element 2, and a second branch line. 2722 extends from the first leg 2721 to increase current spreading. As shown in FIG. 2B, the extension portion 272 includes a protrusion 273 disposed on the electrical contact layer 26 to cover at least one surface of the electrical contact layer 26, increasing the area of the ohmic contact with the electrical contact layer 26, and reducing the light-emitting element 2. The resistance of the protrusion 273 is higher than the current injection portion 271.

Electrical contact layer 26 is located between second leg line 2722 and light emitting stack 25 to form an ohmic contact between second leg line 2722 and light emitting stack 25. The resistance between the electrical contact layer 26 and the second branch 2722 and the resistance between the electrical contact layer 26 and the light-emitting layer 25 are respectively smaller than the resistance between the first electrode 27 and the light-emitting layer 25. The material of the electrical contact layer 26 may be a semiconductor material comprising more than one element selected from the group consisting of gallium (Ga), aluminum (Al), indium (In), phosphorus (P), nitrogen (N), and zinc (Zn). A group of cadmium (Cd) and selenium (Se) may have the same electrical properties as the second semiconductor layer 253.

The material of the light-emitting layer 25 may be a semiconductor material containing more than one element selected from the group consisting of gallium (Ga), aluminum (Al), indium (In), phosphorus (P), nitrogen (N), and zinc (Zn). ), a group of cadmium (Cd) and selenium (Se). The first semiconductor layer 251 and the second semiconductor layer 253 are electrically different to generate electrons or holes. The light-emitting upper surface 254 of one of the second semiconductor layers 253 may be a rough surface to reduce total reflection and enhance the light-emitting efficiency of the photovoltaic element 2. The active layer 252 can emit one or more colored lights, which can be visible or invisible, and can be a single heterostructure, a double heterostructure, a double-sided double heterostructure, a multilayer quantum well or a quantum dot. The electrical property of the window layer 29 can be the same as that of the first semiconductor layer 251, and can be used as a light extraction layer to improve the luminous efficiency of the light-emitting element 2. The window layer 29 is transparent to the light emitted by the active layer 252, and the material thereof may be a transparent conductive material including, but not limited to, indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), and cadmium tin oxide (CTO). ), antimony tin oxide (ATO), aluminum oxide zinc (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO), indium tungsten oxide (IWO), zinc oxide (ZnO), magnesium oxide (MgO), arsenic Aluminum gallium (AlGaAs), gallium nitride (GaN), gallium phosphide (GaP) or indium zinc oxide (IZO).

The transparent conductive structure 23 is transparent to the light emitted by the light-emitting layer 25 for increasing ohmic contact between the window layer 251 and the reflective structure 22 and current conduction and diffusion, and can form an omnidirectional mirror with the reflective structure 22 (Omni -Directional Reflector, ODR). The material may be a transparent conductive material including, but not limited to, indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO), aluminum oxide zinc (AZO). ), zinc tin oxide (ZTO), gallium zinc oxide (GZO), indium tungsten oxide (IWO), zinc oxide (ZnO), gallium phosphide (GaP), indium oxide oxide (ICO), indium oxide tungsten (IWO), Indium titanium oxide (ITiO), indium zinc oxide (IZO), indium gallium oxide (IGO), gallium aluminum oxide (GAZO) or a combination of the above. The transparent conductive structure 23 has a first conductive oxide layer 230 under the non-oxide insulating layer 24 and a second conductive oxide layer 232 between the light emitting layer 25 and the first conductive oxide layer 230. The first conductive oxide layer 230 is different from the second conductive oxide layer 232. In another embodiment, the material of the first conductive oxide layer 230 and the second conductive oxide layer 232 are different from each other by at least one constituent element. For example, the material of the first conductive oxide layer 230 is indium zinc oxide (IZO), and the second conductive material The material of the oxide layer 232 is indium tin oxide (ITO). The second conductive oxide layer 232 may be in direct contact with the non-oxidized insulating layer 24 and/or the window layer 29 and cover at least one surface of the non-oxidized insulating layer 24.

The non-oxide insulating layer 24 has a light transmittance of greater than 90% for the light-emitting layer 25 and a refractive index of less than 1.4, preferably between 1.3 and 1.4. The material of the non-oxide insulating layer 24 may be a non-oxide insulating material such as benzocyclobutene (BCB), cycloolefin polymer (COC), fluorocarbon polymer (Fluorocarbon Polymer), tantalum nitride (SiNx). , calcium fluoride (CaF2) or magnesium fluoride (MgF2). In another embodiment, the material of the non-oxide insulating layer 24 may comprise a halide or a compound of Group IIA and Group VII, such as calcium fluoride (CaF2) or magnesium fluoride (MgF2). The refractive index of the non-oxide insulating layer 24 is smaller than the refractive index of the window layer 29 and the transparent conductive structure 23. Since the refractive index of the non-oxide insulating layer 24 is smaller than the refractive index of the window layer 29 and the transparent conductive structure 23, the critical angle between the interface between the window layer 29 and the non-oxide insulating layer 24 is smaller than the interface between the window layer 29 and the transparent conductive structure 23. Since the critical angle is such that the light emitted from the light-emitting layer 25 is directed toward the non-oxide insulating layer 24, the probability of total reflection at the interface between the window layer 29 and the non-oxide insulating layer 24 increases. In addition, the interface between the window layer 29 and the transparent conductive structure 23 does not form a total reflection and enters the transparent conductive structure 23, and the interface between the transparent conductive structure 23 and the non-oxide insulating layer 24 also forms a total reflection. Therefore, the light-emitting efficiency of the light-emitting element 2 is improved. The transparent conductive structure 23 has a first contact upper surface 231 in contact with the window layer 29. The non-oxide insulating layer 24 has a second contact upper surface 241 in contact with the window layer 29. The first contact upper surface 231 and the second contact upper surface The 241 is substantially at the same horizontal plane, that is, the distance between the first contact upper surface 231 and the light exit upper surface 254 is substantially equal to the distance between the second contact upper surface 241 and the light exit upper surface 254. FIG. 3 is a schematic diagram showing the power of the light-emitting element 2 as a percentage of the surface area of the first contact upper surface 231 relative to the surface area of the first contact upper surface 231 and the second contact upper surface 241. As shown in FIG. 3, when the surface area of the first contact upper surface 231 is about 10% to 50% with respect to the total surface area of the first contact upper surface 231 and the second contact upper surface 241, the power of the light-emitting element 2 is Above 50 mW, the power of the light-emitting element above 50 is preferred. More preferably, the percentage is about 12.5% to 25%, and the power is above 55 mW. In other words, the ratio of the surface area of the non-oxide insulating layer 24 to the window layer 29 to the surface area of the window layer 29 with respect to the non-oxide insulating layer 24 is about 0.5 to 0.9, and the power of the light-emitting element 2 is preferably. In another embodiment, the second contact upper surface 241 can be a rough surface that scatters light emitted by the light emitting stack to enhance the light extraction efficiency of the photovoltaic element 2. The non-oxide insulating layer 24 can have a patterned distribution, such as substantially directly beneath the electrical contact layer 26 and/or the current injection portion 271, to promote diffusion of current. In another embodiment, the non-oxide insulating layer 24 may exhibit an irregular distribution or may be located directly below the electrical contact layer 26 and/or the current injection portion 271. The thickness of the non-oxide insulating layer 24 is smaller than one half of the thickness of the transparent conductive structure 23; in another embodiment, the thickness of the non-oxide insulating layer 24 is less than 1/5 of the thickness of the transparent conductive structure 23 to prevent the transparent conductive structure 23 from being formed. The surface planarization process destroys the structure of the non-oxide insulating layer 24. At least one surface of the non-oxide insulating layer 24 is covered by the transparent conductive layer 23, which increases the bonding between the transparent conductive layer 23 and the window layer 29, and improves the mechanical strength of the structure. In another embodiment, the non-oxide insulating layer 24 can be directly bonded to the reflective structure 22 to prevent insufficient adhesion between the transparent conductive structure 23 and the reflective structure 22, resulting in peeling. The non-oxide insulating layer 24 further includes a plurality of pores 242 passing through the non-oxide insulating layer 24, wherein the transparent conductive structure 23 is filled in the plurality of pores 242 to form an ohmic contact with the window layer 29.

The reflective structure 22 can reflect light from the light emitting stack 25, and the material thereof can be a metal material including, but not limited to, copper (Cu), aluminum (Al), tin (Sn), gold (Au), silver (Ag), lead. (Pb), titanium (Ti), nickel (Ni), platinum (Pt), tungsten (W) or an alloy of the above materials. The reflective structure 22 includes a reflective layer 226; a reflective adhesive layer 224 under the reflective layer 226; a barrier layer 222 under the reflective bonding layer 224; and an ohmic contact layer 220 under the barrier layer 222. The reflective layer 226 can reflect the light from the light emitting layer 25. The reflective bonding layer 224 bonds the reflective layer 226 and the barrier layer 222. The barrier layer 222 prevents the material of the reflective layer 226 from diffusing to the electrode layer 220, and destroys the structure of the reflective layer 226. The reflectance of the reflective layer 226 is lowered, and the ohmic contact layer 220 forms an ohmic contact with the lower conductive adhesive layer 21. The conductive bonding layer 21 can connect the substrate 20 to the reflective structure 22 and can have a plurality of subordinate layers (not shown). The material of the conductive adhesive layer 21 may be a transparent conductive material or a metal material, and the transparent conductive material includes, but not limited to, indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), and cerium oxide. Tin (ATO), Aluminium Zinc Oxide (AZO), Zinc Oxide (ZTO), Gallium Zinc Oxide (GZO), Zinc Oxide (ZnO), Gallium Phosphide (GaP), Indium Oxide (ICO), Indium Oxide ( IWO), indium titanium oxide (ITiO), indium zinc oxide (IZO), indium gallium oxide (IGO), gallium aluminum oxide (GAZO) or a combination of the above. Metal materials include, but are not limited to, copper (Cu), aluminum (Al), tin (Sn), gold (Au), silver (Ag), lead (Pb), titanium (Ti), nickel (Ni), platinum (Pt) , tungsten (W) or an alloy of the above materials.

The substrate 20 can be used to support the light-emitting laminate 25 and other layers or structures thereon, the material of which can be a transparent material or a conductive material. Transparent materials include, but are not limited to, Sapphire, Diamond, Glass, Epoxy, Quartz, Acryl, Al2O3, Zinc Oxide (ZnO) ) or aluminum nitride (AlN) or the like. Conductive materials include, but are not limited to, copper (Cu), aluminum (Al), molybdenum (Mo), tin (Sn), zinc (Zn), cadmium (Cd), nickel (Ni), cobalt (Co), diamond-like carbon film (Diamond Like Carbon; DLC), Graphite, Carbon Fiber, Metal Matrix Composite (MMC), Ceramic Matrix Composite (CMC), Germanium (Si), Phosphating Iodine (IP), zinc selenide (ZnSe), gallium arsenide (GaAs), tantalum carbide (SiC), gallium phosphide (GaP), gallium arsenide (GaAsP), indium phosphide (InP), lithium gallate (LiGaO2) or lithium aluminate (LiAlO2).

4 is a schematic exploded view of a bulb, a bulb 4 has a lamp cover 41; a lens 42 is placed in the lamp cover 41; a lighting module 44 is located under the lens 42; and a lamp holder 45 has a The heat sink 46 is configured to carry the lighting module 44; a connecting portion 47; and an electrical connector 48, wherein the connecting portion 47 connects the socket 45 and the electrical connector 48. The illumination module 44 has a carrier 43; and a plurality of the light-emitting elements 40 of any of the foregoing embodiments are located above the carrier 43.

However, the above embodiments are merely illustrative of the principles and effects of the present application, and are not intended to limit the present application. Modifications and variations of the above-described embodiments can be made without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present application is as set forth in the scope of the patent application described below.

1‧‧‧Lighting device

11‧‧‧LED

12‧‧‧ times carrier

13, 20‧‧‧ substrate

14‧‧‧ Circuitry

15‧‧‧Electrode

16‧‧‧ solder

18‧‧‧Electrical connection structure

2, 40‧‧‧Lighting elements

21‧‧‧ Conductive bonding layer

22‧‧‧Reflective structure

220‧‧ ‧ ohmic contact layer

222‧‧‧ barrier layer

224‧‧‧Reflective bonding layer

226‧‧‧reflective layer

23‧‧‧Transparent conductive structure

230‧‧‧First conductive oxide layer

231‧‧‧First contact upper surface

232‧‧‧Second conductive oxide layer

24‧‧‧Non-oxide insulation

241‧‧‧Second contact upper surface

242‧‧‧ pores

25‧‧‧Lighting laminate

251‧‧‧First semiconductor layer

252‧‧‧Lighting layer

253‧‧‧Second semiconductor layer

254‧‧‧Lighting upper surface

26‧‧‧Electrical contact layer

27‧‧‧First electrode

271‧‧‧ Current Injection Department

272‧‧‧Extension

273‧‧‧ protruding parts

2721‧‧‧first line

2722‧‧‧Second branch

28‧‧‧second electrode

29‧‧‧Window layer

4‧‧‧Light bulb

41‧‧‧shade

42‧‧‧ lens

43‧‧‧ Carrier

44‧‧‧Lighting module

45‧‧‧ lamp holder

46‧‧‧heat sink

47‧‧‧Connecting Department

48‧‧‧Electrical connector

FIG. 1 is a schematic view showing the structure of a conventional light-emitting device.

2A is a top view of a light-emitting element according to an embodiment of the present application.

Fig. 2B is a cross-sectional view taken along line AA' of Fig. 2A.

Figure 3 is a graph showing the percentage versus power of the sum of the surface area of the first contact upper surface relative to the first contact upper surface and the second contact upper surface.

FIG. 4 is a schematic exploded view of a bulb according to an embodiment of the present application.

2‧‧‧Lighting elements

20‧‧‧Substrate

21‧‧‧ Conductive bonding layer

22‧‧‧Reflective structure

220‧‧ ‧ ohmic contact layer

222‧‧‧ barrier layer

224‧‧‧Reflective bonding layer

226‧‧‧reflective layer

23‧‧‧Transparent conductive structure

230‧‧‧First conductive oxide layer

231‧‧‧First contact upper surface

232‧‧‧Second conductive oxide layer

24‧‧‧Non-oxide insulation

241‧‧‧Second contact upper surface

242‧‧‧ pores

25‧‧‧Lighting laminate

251‧‧‧First semiconductor layer

252‧‧‧Lighting layer

253‧‧‧Second semiconductor layer

254‧‧‧Lighting upper surface

26‧‧‧Electrical contact layer

27‧‧‧First electrode

271‧‧‧ Current Injection Department

272‧‧‧Extension

273‧‧‧

28‧‧‧second electrode

29‧‧‧Window layer

Claims (10)

A light-emitting element comprising: a light-emitting layer comprising an active layer; a window layer on the light-emitting layer; an insulating layer comprising a plurality of holes connected to the window layer; a conductive substrate being located under the insulating layer The first electrode is connected to the light emitting layer; the second electrode is connected to the conductive substrate; wherein the first electrode comprises a current injection portion and an extension portion, and the The current injection portion and the extension have the same thickness in the stacking direction of the light emitting laminate. The illuminating element of claim 1, wherein the difference in refractive index between the insulating layer and the window layer is greater than 1.5. The light-emitting element of claim 1, wherein the insulating layer comprises a halide or a compound of Groups IIA and VIIA. The illuminating element of claim 1, further comprising a conductive bonding layer between the conductive substrate and the insulating layer. The illuminating element of claim 4, wherein the electrically conductive bonding layer comprises a metal. The illuminating element of claim 1, further comprising a transparent conductive structure covering a surface of the insulating layer and filling the plurality of pores. The light-emitting element of claim 6, wherein the thickness of the insulating layer in the stacking direction of the light-emitting layer is smaller than the thickness of the transparent conductive structure. The illuminating element of claim 1, wherein the extension is connected to the current injection portion and extends toward a boundary of the illuminating element. The illuminating element of claim 1, further comprising an electrical contact layer between the extension and the luminescent laminate. The illuminating element of claim 9, wherein the insulating layer is located below the electrical contact layer and the current injection portion.