Abstract
An optoelectronic component is disclosed. In an embodiment an optoelectronic component includes a semiconductor chip configured to emit radiation and a conversion element including quantum dots, the conversion element configured to convert a wavelength of the radiation, wherein each quantum dot includes a wavelength-converting core and an inorganic encapsulation, wherein inorganic encapsulations form a matrix material of at least adjacent quantum dots, and wherein the adjacent quantum dots have a distance of at least 10 nm.
Claims
1. An optoelectronic component comprising: a semiconductor chip configured to emit radiation; and a conversion element comprising quantum dots, the conversion element configured to convert a wavelength of the radiation, wherein each quantum dot comprises a wavelength-converting core and an inorganic encapsulation, wherein the adjacent quantum dots have a distance of at least 10 nm, wherein a matrix material directly connects the quantum dots with each other, and wherein the matrix material is formed from the same material as the inorganic encapsulation.
2. The optoelectronic component according to claim 1, wherein wavelength-converting cores of the adjacent quantum dots comprise a distance of at least 10 nm and/or at most 15 nm.
3. The optoelectronic component according to claim 1, wherein the conversion element comprises a thickness which corresponds to at most 30% of a thickness of the semiconductor chip.
4. The optoelectronic component according to claim 1, wherein a thickness of the conversion element is between 0.1 μm and 10 μm.
5. The optoelectronic component according to claim 1, wherein the wavelength-converting cores of the quantum dots comprise InP, CdS, CdSe, InGaAs, GaInP or CuInSe.
6. The optoelectronic component according to claim 1, wherein the optoelectronic component is configured to fully convert the radiation so that the radiation is completely converted in the conversion element.
7. The optoelectronic component according to claim 1, wherein the semiconductor chip is pixelated.
8. The optoelectronic component according to claim 1, wherein the wavelength-converting cores of the quantum dots comprise a diameter of 5 nm to 10 nm.
9. The optoelectronic component according to claim 1, wherein the inorganic encapsulations comprise a diameter of 5 nm to 15 nm, and wherein the diameter of the inorganic encapsulation is on average larger than a diameter of the wavelength-converting cores.
10. The optoelectronic component according to claim 1, wherein the conversion element is arranged directly on a radiation main side of the semiconductor chip.
11. The optoelectronic component according to claim 1, wherein the inorganic encapsulations protect the wavelength-converting cores from degradation.
12. The optoelectronic component according to claim 1, wherein the inorganic encapsulations are formed from a silicate sol-gel material by a wet chemical process and/or wherein the inorganic encapsulations comprises optical scattering centers.
13. The optoelectronic component according to claim 1, wherein the inorganic encapsulations are formed from TEOS or an oxidic precursor material.
14. A method for producing the optoelectronic component according to claim 1, the method comprising: providing the semiconductor chip; and providing the conversion element on the semiconductor chip by: providing the wavelength-converting cores of the quantum dots; applying an inorganic partial encapsulation around the wavelength-converting cores; applying a solution of a material of the inorganic partial encapsulation to the semiconductor chip; and reacting the solution of the material of the inorganic partial encapsulation with the wavelength-converting cores of the quantum dots which are surrounded by the inorganic partial encapsulation so that the inorganic encapsulations are produced.
15. The optoelectronic component according to claim 1, wherein the matrix material is free of organic materials.
16. The optoelectronic component according to claim 1, wherein a region between adjacent quantum dots is completely filled with the matrix material.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Further advantages, advantageous embodiments and developments result from the exemplary embodiments described in the following in connection with the figures.
(2) FIGS. 1A to 1F each show quantum dots according to an embodiment or a comparative example;
(3) FIGS. 2A, 2C, 2D each show a schematic side view of a conversion element according to an embodiment;
(4) FIG. 2B shows a schematic side view of an optoelectronic component according to an embodiment; and
(5) FIGS. 3A to 3G each show a schematic side view of an optoelectronic component according to an embodiment.
(6) In the exemplary embodiments and figures, identical, similar or equivalent elements can each be provided with the same reference numbers. The represented elements and their proportions among each other are not to be regarded as true to scale. Rather, individual elements, such as layers, components, components and areas, can be displayed in an exaggeratedly large format for better representability and/or better understanding.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
(7) FIG. 1A shows a schematic side view of a quantum dot 3. In particular, only the wavelength-converting core 31 is shown here. The wavelength-converting core 31 comprises or consists of indium phosphide, cadminum selenide, cadmium sulphide and/or copper indium selenide or combinations thereof.
(8) According to FIG. 1B, an inorganic encapsulation 4 is arranged around the wavelength-converting core 31. The inorganic encapsulation can be formed, for example, from silicon dioxide or SolGel oxides (e.g., TEOS based). A matrix material 5 can be arranged around the inorganic encapsulation 4, as in this case.
(9) The quantum dots can have a core of CdSe or InP with a diameter of 2-10 nm. This allows the emission spectra to be defined. The core can be surrounded by a CdS or ZnS shell which defines the optical absorption and protects the core.
(10) The quantum dots may be encapsulated in an oxide to protect them from the environment.
(11) The oxide can grow together to form the matrix and protect the individual quantum dots and ensure that the outer quantum dot surfaces are separated by >10 nm.
(12) According to FIG. 1C, a quantum dot 3 is shown with a wavelength-converting core 31 and an inorganic encapsulation 4. The inorganic encapsulation 4, which consists exclusively of inorganic materials, i.e., contains no organic materials, surrounds the wavelength-converting core 31 in a cohesive and form-fitting manner.
(13) According to FIG. 1D, a quantum dot is shown here which has the diameter d.sub.K of the wavelength-converting core 31. The diameter of the inorganic encapsulation 4 d.sub.V is also shown. These diameters are to be assumed in particular if the quantum dots are shaped as spherical spheres. Alternatively, these diameters can also be assumed if the quantum dots are rod-shaped.
(14) FIG. 1E shows the distance from adjacent quantum dots. The ‘distance from adjacent quantum dots’ can be the shortest distance from adjacent wavelength-converting cores 31, measured from the center of the respective wavelength-converting core (d.sub.maxK). Alternatively, in particular, the shortest distance between the respective outer sides or outer surfaces of the wavelength-converting cores 31 can be meant (d.sub.maxKA).
(15) FIG. 1F shows the distance between adjacent quantum dots (d.sub.maxVV), i.e., the shortest distance measured from the outer sides of the inorganic encapsulation of the respective quantum dots. In particular, d.sub.maxVV is <10 nm.
(16) FIG. 2A shows a schematic side view of a conversion element according to an embodiment. Four quantum dots 3 are shown here. Each quantum dot has a wavelength-converting core 31 and an inorganic encapsulation 4. The inorganic encapsulation surrounds the respective wavelength-converting core 31 in a cohesive and form-fitting manner. A matrix material 5 may be present around the encapsulation 4. The matrix material 5 is preferably formed from the same material as the inorganic encapsulation 4. In other words, the inorganic encapsulation 4 connects the quantum dots with each other, so that further matrix materials are not necessary. In addition, the quantum dots have a minimum distance or a maximum distance of, for example, 10 nm, with a tolerance of 1%, 2%, 3%, 4% or 5% deviation from this value.
(17) FIG. 2B shows a schematic side view of an optoelectronic component according to an embodiment. A semiconductor chip 1 is shown here, which is configured to emit radiation, in particular radiation from the blue wavelength range. A conversion element 2 is arranged on the semiconductor chip 1, especially directly on the radiation exit surface of the semiconductor chip 1. The conversion element 2 comprises the quantum dots described here with the wavelength-converting core 31 and the inorganic encapsulation 4. The layer thickness of the semiconductor chip 1l.sub.H is many times greater than the layer thickness of the conversion element 2l.sub.K. Preferably, the conversion element 2 comprises a layer thickness that corresponds to a maximum of 10%, 20%, 30%, 40%, 50% or 60% of the layer thickness of the semiconductor chip. For example, the layer thickness of the semiconductor chip has a thickness of 5 μm. Then, for example, the layer thickness of the conversion element 2 comprises a layer thickness of approximately 1 μm. Alternatively, the relation between the pixel “footprint” (x-y dimension) and the conversion element thickness (z) can also be made. For 5×5 μm pixels, for example, the layer thickness of the conversion element is then less than 5 μm.
(18) FIG. 2C shows a schematic side view of a conversion element 2 according to an embodiment. Here the quantum dots with the wavelength-converting core 31 and the inorganic encapsulation 4 are arranged in direct mechanical or electrical contact with each other.
(19) In comparison, FIG. 2D shows that the inorganic encapsulations 4 of the respective quantum dots, which are arranged adjacent to each other, are spaced apart. The intermediate regions between adjacent inorganic encapsulations can be filled with a material that is the same as the material of the inorganic encapsulation.
(20) FIGS. 3A to 3G show a schematic side view of an optoelectronic component 100 according to an embodiment.
(21) The component in FIG. 3A comprises a carrier 7 on which a semiconductor chip 1 is arranged. The semiconductor chip 1 is configured to emit radiation, in particular radiation from the blue wavelength range. The semiconductor chip 1 can be pixelated. In the beam path of the semiconductor chip 1, the conversion element 2 is arranged in particular directly on the radiation exit surface. The lateral surfaces of the semiconductor chip 1 and the conversion element 2 are surrounded by a reflection element 6. The reflection element 6 may contain silicone and scattering particles embedded therein, for example, titanium dioxide, silicon dioxide, zirconium oxide or aluminium oxide.
(22) As shown in FIG. 3B, a conversion element 2 and a lens 8 are arranged on a semiconductor chip 1. The lens 8 can be formed from silicone, for example.
(23) According to FIG. 3C, the carrier 7 has a greater lateral extent than the lateral extent of the semiconductor chip 1 and the conversion element 2. In this case, the lateral extent of the semiconductor chip 1 and the conversion element 2 is the same, but can also be different. For example, the conversion element 2 can extend beyond the semiconductor chip 1.
(24) According to FIG. 3D, the conversion element 2 surrounds the radiation exit surface and the lateral surface of the semiconductor chip 1 in a cohesive and form-fitting manner. In other words, the conversion element 2 completely surrounds the semiconductor chip 1.
(25) According to FIG. 3E, the component comprises a housing 21 with a recess 10. The semiconductor chip 1 is located in the recess 10. The semiconductor chip 1 can be encapsulated within the recess 10 with a potting material 9. The conversion element 2 can be arranged on the housing 21 at a distance from the semiconductor chip 1.
(26) According to FIG. 3F, the conversion element 2 completely surrounds the lateral surfaces and radiation exit surface of the semiconductor chip 1 within a housing 21. In addition, the conversion element 2 can be provided with a potting 9 within the recess.
(27) According to FIG. 3G, the semiconductor chip 1 is completely embedded in the conversion element 2. Compared to the component in FIG. 3D, the carrier 7 is missing.
(28) The exemplary embodiments described in connection with the figures and their features can also be combined with each other according to further exemplary embodiments, even if such combinations are not explicitly disclosed in connection with the figures. Furthermore, the exemplary embodiments described in connection with the figures can have additional or alternative features according to the description in the general part.
(29) The invention is not limited by the description based on the exemplary embodiments of these. Rather, the invention includes any new feature as well as any combination of features, which in particular includes any combination of features in the patent claims, even if this feature or this combination itself is not explicitly specified in the patent claims or exemplary embodiments.
