Optoelectronic component and optoelectronic apparatus

Abstract

The invention relates to an optoelectronic component comprising a photoactive zone, a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a first diffusion barrier layer or a first heterojunction barrier layer. The potential change generated thereby reduces the diffusion or migration of point defects and hydrogen in the optoelectronic component. This advantageously improves the service life of the optoelectronic components, in particular of light-emitting diodes. The invention also relates to an optoelectronic apparatus comprising an optoelectronic component of this type.

Description

[0001] OPTOELECTRONIC COMPONENT AND OPTOELECTRONIC DEVICE

[0002] DESCRIPTION

[0003] The invention relates to an optoelectronic component based on semiconductor materials, for example a light-emitting diode, and to an optoelectronic device which includes such an optoelectronic component.

[0004] Optoelectronic components, and especially light-emitting diodes (LEDs), have a wide range of applications. They have long been used in lighting, particularly where very high light output is required. For example, LEDs are used in the automotive industry.

[0005] Optoelectronic components are based on the fact that electrical energy is converted into electromagnetic radiation in a photoactive zone, as in light-emitting diodes, or electromagnetic radiation into electrical energy, as in solar cells.

[0006] Light-emitting diodes, for example, have a pn junction in the photoactive zone, in which electrons and holes recombine due to an applied voltage and electromagnetic radiation is generated.

[0007] It is relevant to adapt the properties of optoelectronic components, and especially light-emitting diodes, in order to expand their areas of application and improve their functionality. The present invention is based on the objective of providing an optoelectronic component that exhibits improved properties.

[0008] According to the present invention, the problem is solved by the subject matter of the dependent claims. Advantageous further developments are specified in the dependent claims.

[0009] SUMMARY

[0010] The problem is solved by the subject matter of the dependent claims. Further embodiments are specified in the dependent claims.

[0011] In particular, the problem is solved by an optoelectronic component comprising a photoactive zone. The photoactive zone can be formed from a semiconductor material, which is, for example, a compound semiconductor material such as AlGaN or InGaN.

[0012] The optoelectronic component also has a first semiconductor layer of a p-type conductivity type and a second semiconductor layer of an n-type conductivity type.

[0013] In this arrangement, a first diffusion barrier layer is formed in or adjacent to the photoactive zone on one side of the first semiconductor layer. The first diffusion barrier layer is located at an end of the photoactive zone facing the first semiconductor layer. Optionally, the first diffusion barrier layer is also located adjacent to at least one of the outer interfaces of the photoactive zone. According to possible embodiments, no electron blocking layer is arranged between the photoactive zone and the first diffusion barrier layer. The first diffusion barrier layer can have as its base material the semiconductor material from which the photoactive zone is formed, which, in the context of this disclosure, means that the diffusion barrier layer optionally contains the elements from which the photoactive zone is formed.The ratios of the individual elements to each other in the diffusion barrier layer can be identical or different to the ratio of the elements in the photoactive zone or to at least a sublayer of the photoactive zone.

[0014] The first diffusion barrier layer also contains foreign atoms of a first element. These foreign atoms are selected such that a potential difference of ±1 meV to ±2 eV, for example, ±5 meV to ±800 meV, 1 meV to 2 eV, or 5 meV to 800 meV, is formed between the diffusion barrier layer and a section of the photoactive zone adjacent to the diffusion barrier layer. Different types of bonds can exist between the foreign atoms and the atoms surrounding them. Optionally, the atoms surrounding the foreign atoms can correspond to the lattice structure of the first diffusion barrier layer surrounding the foreign atoms.

[0015] The type of foreign atoms, i.e., which element is involved, and their concentration in the diffusion barrier layer can depend on the chosen semiconductor material that forms the photoactive zone and / or the diffusion barrier layer. The foreign atoms possess different binding energies and generate a potential difference. This potential difference arises between the photoactive zone and the diffusion barrier layer in the case of diffusion barrier layers adjacent to the photoactive zone. The same applies in the embodiment where the diffusion barrier layer is formed within the photoactive zone. In this case, the effect is reversed, so that a different sign should be observed for diffusion depending on the charge of the diffusing defects.

[0016] The foreign atoms can be selected such that their binding energy differs from the binding energy of the surrounding lattice structure by a value between ±1 meV and ±2 eV. Various methods can be used for characterization, i.e., for determining the binding energy. For example, the binding energy can be determined using low-temperature photoluminescence, X-ray photoelectron spectroscopy, secondary ion mass spectrometry, energy-dispersive X-ray spectroscopy in combination with a transmission electron microscope (TEM EDX), or atom probe tomography.

[0017] This applies to AlGaN systems, i.e., when the photoactive zone Al x Gai- x N has and the first diffusion barrier layer (6) Al yGai-yN with 0 <x,y<l aufweist, beispielsweise auf Bor, Silizium und Magnesium zu. Die Fremdatome können also aus Bor und / oder Silizium und / oder Magnesium ausgebildet sein.

[0018] According to one embodiment, the photoactive zone Al x Gai- x N has and the first diffusion barrier layer (6) Al y Gai- y N with 0 <x,y<l auf.

[0019] The foreign atoms can be present in a dopant concentration of 10 15 - 10 20 cm -3 for example, in a dopant concentration of 10 15 — 10 18 cm -3 optionally in a dopant concentration of 10 15 -

[0020] 10 17 cm -3The diffusion barrier layer is present in the first diffusion barrier layer. This layer can advantageously prevent or at least reduce the diffusion of point defects from the p-side into the photoactive zone. Furthermore, the first diffusion barrier layer also acts as a migration barrier for the hydrogen located in the photoactive zone, thereby increasing the proportion of hydrogen in the photoactive zone. This results in fewer vacancies during operation and thus a longer lifetime for the optoelectronic device.

[0021] One reason for the improved lifespan is that aging can result from the dehydration of vacancies of an element, such as gallium, during the operation of an optoelectronic component made of, for example, AlGaN. Such dehydration leads to reduced hole injection, thereby decreasing the luminous efficacy. This can be advantageously prevented by the diffusion barrier layer, as a potential difference can be created there. Thus, by introducing foreign atoms, a bond different from that of the surrounding semiconductor material, such as AlGaN, is created, which prevents the diffusion of hydrogen and / or the diffusion of point defects.

[0022] The first Df fusion barrier layer can also consist of several sublayers. In particular, the optoelectronic device can also have several first Df fusion barrier layers. This can be realized, in particular, if the first Df fusion barrier layer is located in the photoactive zone and the photoactive zone consists of several sublayers. In this case, for example, several quantum film layers can be formed as the first Df fusion barrier layer. A photoactive zone can be formed from several sublayers in the context of this disclosure and can also be referred to as a photoactive zone.

[0023] The optoelectronic component is designed, for example, as a light-emitting diode.

[0024] According to an optional embodiment, the first diffusion barrier layer is formed adjacent to the photoactive zone, wherein the first diffusion barrier layer is arranged between the photoactive zone and the first or the second semiconductor layer.

[0025] According to its embodiment, the optoelectronic device has a second diffusion barrier layer. This second diffusion barrier layer is positioned between the photoactive zone and the second semiconductor layer. The base material of the second diffusion barrier layer can be the same semiconductor material as the photoactive zone, and it may also contain foreign atoms of a second element, for example, at a dopant concentration of 10⁻⁵. 15 -10 18 cm -3In one possible configuration, the first and second elements are identical elements, for example, silicon. In an alternative configuration, the first and second elements are different elements, such as silicon and magnesium.

[0026] The first and second diffusion barrier layers can then prevent the diffusion of point defects from both the p- and n-sides, thus contributing to long-lasting luminescence. Hydrogen migration can thereby be prevented or reduced in both directions, i.e., towards the first semiconductor layer and towards the second semiconductor layer. In the context of this disclosure, the photoactive zone is suitable for emitting or absorbing electromagnetic radiation, for example, converting electrical energy into the emission of electromagnetic radiation. The photoactive zone is configured, for example, as a sequence of sublayers, in particular quantum film layers and barrier layers, to form a quantum well structure.

[0027] For example, at least one, or optionally at least two, of the quantum film layers is configured as the first diffusion barrier layer. In one possible embodiment, all quantum film layers are configured as the first diffusion barrier layer.

[0028] One embodiment provides that at least one of the barrier layers is designed as the first diffusion barrier layer; according to another embodiment, at least two of the barrier layers are designed as the first diffusion barrier layer. In one possible embodiment, all barrier layers are designed as the first diffusion barrier layer.

[0029] According to the implementation methods, at least one of the quantum film layers and at least one of the barrier layers can be configured as the first Df fusion barrier layer. Optionally, at least two, at least three, at least four, or all of the sublayers in the photoactive zone can be configured as the first Df fusion barrier layer.

[0030] For example, the first diffusion barrier layer is located at the end of the photoactive zone facing the p-contact. The first diffusion barrier layer is either located between the photoactive zone and the p-contact, or it is located within the photoactive zone, in which case the end of the photoactive zone facing the p-contact is part of the first diffusion barrier layer. In the case of multiple quantum film layers, at least one, for example at least two, of the quantum film layers facing the p-contact is configured as a first diffusion barrier layer.

[0031] The foreign atoms contained in the first diffusion barrier layer are, for example, donors for the semiconductor material. These foreign atoms are selected to be suitable for n-type doping, meaning they can increase the number of electrons in the conduction band.

[0032] For example, the first or second diffusion barrier layer is located at the end of the photoactive zone facing the n-contact. The foreign atoms contained in the first diffusion barrier layer are then, for example, acceptors, and thus suitable for p-doping.

[0033] For example, the foreign atoms are selected from silicon and / or boron and / or magnesium.

[0034] In an advantageous embodiment, the first diffusion barrier layer contains foreign atoms, which are composed of at least one type of foreign atom and one type of foreign atom. The first type is a donor for the semiconductor material, thus suitable for n-type doping, and the second type of foreign atom is an acceptor for the semiconductor material, thus suitable as a p-type dopant. The ratio of the first type of foreign atom to the second type of foreign atom is, for example, in the range of 1.5 to 15.0 or from 1:15 to 1:1.5, or, according to one embodiment, in the range of 2.0 to 10.0 or from 1:10 to 1:2. The first diffusion barrier layer and / or the second diffusion barrier layer has, for example, a maximum thickness of 120 nm.According to one implementation form, the thickness of the diffusion barrier layer is in the range of 0.5 nm to 100 nm, for example in the range of 1 nm to 20 nm.

[0035] The task can also be solved by an optoelectronic component which may have a photoactive zone made of a semiconductor material, for example a compound semiconductor material such as AlGaN or InGaN.

[0036] The optoelectronic device comprises a first semiconductor layer of a first conductivity type and a second semiconductor layer of a second conductivity type. A first heterojunction barrier layer is formed in or adjacent to the photoactive zone. The first heterojunction barrier layer is thus arranged adjacent to at least one of the outer interfaces of the photoactive zone.

[0037] According to the implementation forms, no electron blocking layer is arranged between the photoactive zone and the first heterojunction barrier layer.

[0038] The first heterojunction barrier layer is designed and arranged such that a heterojunction is formed between the first heterojunction barrier layer and the photoactive zone. For example, the heterojunction barrier layer has a larger band gap than the photoactive zone.

[0039] Zone. For example, the heterojunction barrier layer has a band gap that is 1 meV to 2 eV larger than the adjacent photoactive zone layer. According to certain embodiments, the heterojunction barrier layer also has a band gap that is 1 meV to 2 eV larger than the p- and / or n-side, i.e., larger than the first semiconductor layer and / or the second semiconductor layer.

[0040] By introducing such a heterojunction barrier layer, a potential step or potential change, i.e., a potential difference in the range of ±1 meV and ±2 eV, for example in the range of ±5 meV and ±800 meV, can be generated. Thus, heterojunctions can create a bond that differs from that of the surrounding semiconductor material, such as AlGaN, which prevents or at least reduces the diffusion of hydrogen and / or the diffusion of point defects.

[0041] For example, this allows the diffusion of defects, especially point defects, to be controlled separately from the transport of charge carriers.

[0042] According to one implementation, the first heterojunction barrier layer is formed from an intrinsic material, i.e., without introduced dopants. The Fermi level lies in the band gap, for example, in the middle of the band gap.

[0043] According to an advantageous embodiment, the elements of the first semiconductor material differ in the photoactive zone and the elements in the diffusion barrier layer.

[0044] An advantageous embodiment provides that the semiconductor material of the photoactive zone is a compound semiconductor material comprising a first, a second, and a third compositional element. The first heterojunction barrier layer is formed from a semiconductor material comprising two of these compositional elements, i.e., the first and the second compositional element, or the first and the third compositional element, or the second and the third compositional element.

[0045] Advantageously, the diffusion of point defects and the migration of hydrogen can be prevented or reduced without the need to introduce foreign atoms into the structure.

[0046] According to an advantageous embodiment, the semiconductor material of the photoactive zone is a compound semiconductor material AxBi-xC, which contains a first compositional element A, a second compositional element B, and a third compositional element C, wherein the first heterojunction barrier layer is a compound semiconductor material made of two of the three compositional elements, where x = l or x = 0. For example, A = aluminum, B = gallium, and C = nitrogen, i.e., a variant of AlGaN. With this material, emission in the UV-C range can advantageously be achieved.

[0047] According to one embodiment, the first heterojunction barrier layer is formed as a superlattice composed of superlattice sublayers. The superlattice comprises at least two superlattice sublayers, with the two superlattice sublayers forming a heterojunction with each other. According to one embodiment, a first heterojunction barrier layer formed as a superlattice is adjacent to the photoactive zone, i.e., adjacent to at least one of the outer interfaces of the photoactive zone.

[0048] According to the present disclosure, a superlattice is a periodic sequence with at least one period of at least two sublayers, optionally with at least two periods of at least four sublayers. The sublayers themselves can also consist of further periodic sublayers. The thicknesses of the different sublayers can vary. Each of the sublayers has a thickness of at least one monolayer.

[0049] The sublayers have a thickness in the range of 0.5 nm to 8 nm, for example from 1 nm to 5 nm. According to one possible embodiment, the superlattice sublayers each have a thickness of one monolayer of the semiconductor material.

[0050] In one advantageous embodiment, the semiconductor material of the photoactive zone is a compound semiconductor material comprising a first, a second, and a third compositional element. Each superlattice sublayer comprises two of the compositional elements from which the compound semiconductor material of the photoactive zone is formed. According to one embodiment, each superlattice sublayer is composed of at least 90%, possibly at least 98%, or entirely of two of the three compositional elements.

[0051] According to one embodiment, the optoelectronic device has a second heterojunction barrier layer, which is formed and arranged between the photoactive zone and the second semiconductor layer in such a way that a heterojunction is formed between the second heterojunction barrier layer and the photoactive zone.

[0052] Such a second heterojunction barrier layer can be configured like a first heterojunction barrier layer. The features of the possible implementations of the first heterojunction barrier layer are also, in possible implementations, features of the second heterojunction barrier layer. One possible implementation involves the photoactive zone forming a quantum well structure, for example, as a sequence of sublayers, such as quantum film layers and barrier layers. At least one of the quantum film layers is adjacent to and arranged next to a first heterojunction barrier layer, and a heterojunction is formed between the quantum film layer and the adjacent first heterojunction barrier layer. For example, the first heterojunction layer is arranged between a quantum film layer and a barrier layer.

[0053] The thickness of the first heterojunction barrier layer, according to one implementation form, lies in a range of 0.2 nm to 10 nm, for example in a range of 0.5 nm to 8 nm, for example in a range of 2 nm to 5 nm.

[0054] The thickness of the second heterojunction barrier layer, according to one embodiment, lies in a range of 0.2 nm to 10 nm, for example in a range of 0.5 nm to 8 nm, for example in a range of 2 nm to 5 nm.

[0055] For example, at least two of the quantum film layers are formed and arranged adjacent to a first heterojunction barrier layer, such that a heterojunction is formed in each case. Several first heterojunction barrier layers can be formed.

[0056] According to one implementation, all quantum film layers are formed and arranged adjacent to a first heterojunction barrier layer, such that a heterojunction is formed in each case. For example, the semiconductor material of the photoactive zone is a compound semiconductor material A. X B!- XC, which contains a first compositional element A, a second compositional element B, and a third compositional element C, wherein the first heterojunction barrier layer is a compound semiconductor material made of two of the three compositional elements, where x = l or x = 0. According to one possible embodiment, quantum film layers and barrier layers are formed from different compositions of the three compositional elements, where X lies in a range from 0.1 to 0.9, and wherein a Df fusion barrier layer is arranged between at least one of the quantum film layers and one of the barrier layers, wherein the Df fusion barrier layer is a compound semiconductor material made of two of the three compositional elements, where x = l or x = 0. For example, A = aluminum, B = gallium, and C = nitrogen.

[0057] According to one embodiment, the first heterojunction barrier layer is arranged at the end of the photoactive zone facing the p-contact.

[0058] According to one possible embodiment, the optoelectronic device has a dif fusion barrier layer and a heterojunction barrier layer as described herein.

[0059] In an advantageous embodiment, the optoelectronic component is designed as a light-emitting diode (LED). For example, the semiconductor composite system is aluminum gallium nitride (AlGaN). This semiconductor composite system can emit very short-wavelength UVC radiation in the wavelength range of 200 nm to 280 nm. This wavelength range is particularly well-suited for disinfection, as bacteria and viruses are especially sensitive to it. Since UVC radiation is almost entirely absent in natural light, they have not developed any defense mechanisms against it.

[0060] According to one embodiment, the optoelectronic components have a potential stage or potential barrier, which is formed either by a first diffusion barrier layer containing foreign atoms to shift the Fermi level, or by a first heterobarrier transition layer which, due to the materials used and the special structure, generates a heterotransition to the photoactive zone.

[0061] The resulting potential step or potential barrier reduces the diffusion or migration of point defects and hydrogen in the optoelectronic component. This advantageously improves the lifetime of the optoelectronic components, especially light-emitting diodes.

[0062] This makes LEDs attractive for further applications and more competitive with existing systems. For several years, the use of LEDs in the UV range, particularly in the UV-C range, has gained significant importance. Light in this wavelength range is suitable for various applications, such as disinfection, phototherapy in medicine, plant illumination, and water purification. LEDs offer advantages over other light sources because they can be small, require lower voltage, and their light has a narrow bandwidth.

[0063] Since this requires high power outputs and therefore high electrical currents, the resulting increased aging processes are very relevant for this type of application.

[0064] The invention advantageously allows the functionality and efficiency to be maintained at a high level over a long period, as aging processes are minimized. This allows the external quantum efficiency to be increased after a certain time, thereby improving the lifespan.

[0065] The accompanying drawings serve to illustrate exemplary embodiments of the invention. The drawings depict these embodiments and, together with the description, serve to explain them. Further exemplary embodiments and many of the intended advantages will become apparent from the detailed description below. The elements and structures shown in the drawings are not necessarily drawn to scale. Identical reference symbols refer to identical or corresponding elements and structures.

[0066] They show:

[0067] Fig. 1 shows a cross-sectional view of an optoelectronic semiconductor device with a first and a second diffusion barrier layer according to embodiments.

[0068] Fig. 2 shows a cross-sectional view of an optoelectronic semiconductor device with a first diffusion barrier layer according to further embodiments.

[0069] Fig. 3A shows a cross-sectional view of an optoelectronic semiconductor device with several first diffusion barrier layers according to further embodiments.

[0070] Fig. 3B shows a cross-sectional view of an optoelectronic

[0071] Semiconductor device with several first diffusion barrier layers according to further embodiments.

[0072] Fig. 4 shows a cross-sectional view of an optoelectronic

[0073] Semiconductor device with a first and a second heterojunction barrier layer according to further

[0074] From implementation forms. Fig. 5 a cross-sectional view of an optoelectronic semiconductor device with several first heterojunction barrier layers according to further implementation forms.

[0075] Fig. 6 shows a schematic band model of an optoelectronic semiconductor device with a first diffusion barrier layer according to further embodiments.

[0076] Fig. 7 shows a schematic band model of an optoelectronic semiconductor device with a first heterojunction barrier layer according to further embodiments.

[0077] Fig. 8 shows an embodiment of an optoelectronic device.

[0078] DE TAIL LBE SCHRE I BUNG

[0079] The following detailed description refers to the accompanying drawings, which form part of the disclosure and show specific embodiments for illustrative purposes. In this context, directional terminology such as "top," "bottom," "front," "back," "over," "on," "in front," "behind," "front," "back," etc., refers to the orientation of the figures just described. Since the components of the embodiments can be positioned in different orientations, the directional terminology serves only for explanation and is in no way restrictive.

[0080] The description of the exemplary embodiments is not limiting, as other exemplary embodiments exist and structural or logical modifications can be made without deviating from the scope defined by the patent claims. In particular, elements of the exemplary embodiments described below can be combined with elements of other described exemplary embodiments, unless otherwise indicated by the context.

[0081] The terms "wafer" or "semiconductor substrate" used in the following description can encompass any semiconductor-based structure that has a semiconductor surface. Wafer and structure are to be understood as including doped and undoped semiconductors, epitaxial semiconductor layers, optionally supported by a substrate, and other semiconductor structures. For example, a layer of a first semiconductor material may be grown on a growth substrate of a second semiconductor material, such as a GaAs substrate, a GaN substrate, or a Si substrate, or of an insulating material, such as on a sapphire substrate.

[0082] Depending on its intended use, a semiconductor can be based on a direct or indirect semiconductor material. Examples of semiconductor materials particularly suitable for generating electromagnetic radiation include nitride semiconductor compounds, which can produce, for example, ultraviolet, blue, or longer-wavelength light, such as GaN, InGaN, AIN, AlGaN, AlGalnN, AlGalnBN; phosphide semiconductor compounds, which can produce, for example, green or longer-wavelength light, such as GaAsP, AlGalnP, GaP, AlGaP; and other semiconductor materials such as GaAs, AlGaAs, InGaAs, Al InGaAs, SiC, ZnSe, ZnO, Ga₂Oa, diamond, hexagonal BN, and combinations of these materials. The stoichiometric ratio of the compound semiconductor materials can vary. Other examples of semiconductor materials include silicon, silicon-germanium, and germanium.In the context of this description, the term "semiconductor" also includes organic semiconductor materials. The term "substrate" generally encompasses insulating, conductive, or semiconductor substrates.

[0083] Where the terms "have", "contain", "comprise", "exhibit", and the like are used here, they are open terms that indicate the presence of the elements or characteristics in question, but do not exclude the presence of further elements or characteristics. The indefinite and definite articles include both the plural and the singular, unless the context clearly indicates otherwise.

[0084] Examples of optoelectronic semiconductor devices are described below. Light-emitting diodes (LEDs) are described in particular. However, the concepts can also be applied to other optoelectronic semiconductor devices and are therefore not limited to LEDs. Further specific examples include semiconductor laser devices, such as surface-emitting semiconductor laser devices, photodetectors, sensors, and others.

[0085] Fig. 1 shows a schematic cross-section of an optoelectronic device 1. The optoelectronic device 1 can have a first semiconductor layer 2 of a first conductivity type, for example p-doped AlGaN, and a second semiconductor layer 3 of a second conductivity type, for example n-doped AlGaN. A photoactive zone 4 can be arranged between the first semiconductor layer 2 and the second semiconductor layer 3. The photoactive zone 4 can, as in this example, have sublayers for forming a quantum well structure. Such sublayers can be quantum film layers 41 and barrier layers 42. A substrate and contact elements are not shown here. To form the quantum well structure, the barrier layers 42 can, for example, have a larger band gap than the quantum film layers 41.This allows the electrons in the quantum film layers 41 to be quantized if the layer thickness of the quantum film layers is smaller than the de Broglie wavelength of the electrons. The resulting quantum well structure can consist of a single quantum film and be configured as a single quantum well (SQW), or it can consist of multiple quantum film layers 42 and thus be configured as a multi-quantum well (MQW). The term "quantum well structure" here has no significance with regard to the dimensionality of the quantization. It therefore includes, among other things, quantum wells, quantum wires, and quantum dots, as well as any combination of these layers.

[0086] In one advantageous embodiment, the first semiconductor layer 2 can be p-type, and an electron-blocking layer 5 can be arranged adjacent to this first semiconductor layer 2. According to one embodiment, this electron-blocking layer 5 has a larger band gap than the quantum film layers 41. To prevent electrons from moving towards the p-type first semiconductor layer 2 while still allowing holes sufficient opportunity to penetrate the photoactive zone, the electron-blocking layer 5 can be p-doped.

[0087] Adjacent to the second semiconductor layer 3, a buffer layer 8, for example made of AIN, can be arranged. This forms, for example, the transition to the substrate (not shown here). This buffer layer can, for example, reduce the density of threading dislocations. Furthermore, it can be used to adjust strain. The thickness of the buffer layer 8 can be, for example, up to 10 pm. The buffer layer 8 can also be omitted. According to one possible embodiment, the buffer layer is omitted if a native substrate, for example made of AIN, is used.

[0088] A first diffusion barrier layer 6 can be arranged adjacent to the photoactive zone 4 between the first semiconductor layer 2 and the photoactive zone 4. The diffusion barrier layer 6 can therefore be arranged between the photoactive zone 4 and the electron blocking layer 5.

[0089] This diffusion barrier layer 6 can be formed from a base material and can also contain foreign atoms in a dopant concentration of 10 15 — 10 18 cm -3 exhibit. The base material can be the semiconductor material from which the photoactive zone is formed. In the context of the present disclosure, this means that the diffusion barrier layer 6 can contain the elements from which the photoactive zone 4 is also formed.

[0090] To form such a diffusion barrier layer 6, which is formed, for example, from a composite semiconductor material such as AlGaN as the base material and contains silicon atoms as foreign atoms, a dopant, such as silicon, can be briefly introduced during epitaxy before or after the growth of the photoactive zone 4, along with the other starting materials for the growth of the composite semiconductor material such as AlGaN, in order to grow a diffusion barrier layer 6. Following the growth of the diffusion barrier layer 6, the dopant can be removed, and the normal growth of the photoactive zone 4 or the electron blocking layer and the first semiconductor layer 2 can continue. The first diffusion barrier layer 6 can advantageously prevent or at least reduce the diffusion of point defects from the p-side into the photoactive zone 4.Furthermore, the diffusion barrier layer 4 also acts as a migration barrier for the hydrogen located in the photoactive zone 4, thereby increasing the proportion of hydrogen in the photoactive zone 4. This results in fewer vacancies during operation and thus a longer service life. The foreign atoms are selected from silicon, magnesium, and boron according to a specific design.

[0091] The thickness of the first diffusion barrier layer 61 is optionally a maximum of 120 nm and, according to one embodiment, lies in the range of 0.5 nm and 100 nm.

[0092] Thanks to the small thickness of the first diffusion barrier layer 61, there is little or no influence on the overlap of the electron and hole wave functions and therefore no influence on the radiative recombination rate.

[0093] Furthermore, a second diffusion barrier layer 7 can be arranged between the second semiconductor layer 3 and the photoactive zone 4. In this embodiment, the second diffusion barrier layer 7 can also be arranged adjacent to the photoactive zone 4, where it can be adjacent to a sublayer of the photoactive zone 4 designed as a barrier layer 42.

[0094] The second diffusion barrier layer 7 can also contain foreign atoms, whereby these second foreign atoms can be identical to the first foreign atoms of the first diffusion barrier layer 6. According to one embodiment, the same elements can be used as the first foreign atoms for the first diffusion barrier layer 6 and as the second foreign atoms for the second diffusion barrier layer 7. Optionally, the first and second foreign atoms can also be composed of different elements.

[0095] The foreign atoms are selected, for example, to dope with a different conductivity type compared to the corresponding adjacent semiconductor layer. Thus, the first diffusion barrier layer 6, which is arranged between the photoactive zone 4 and the first semiconductor layer 2, can contain foreign atoms that are n-type dopants for the semiconductor material if the first semiconductor layer 2 is configured as a hole-type conducting layer. If the first semiconductor layer 2 is configured as an electron-type conducting layer, the foreign atoms can, for example, be p-type dopants for the semiconductor material.

[0096] A cross-section with a first diffusion barrier layer 6, which has a first and a second type of foreign atoms, is shown in Fig. 2. The first type of foreign atoms can be a donor for the semiconductor material, for example silicon for AlGaN, and the second type of foreign atoms can be an acceptor for the semiconductor material, for example magnesium for AlGaN. The ratio of donors to acceptors can be in the range of 0.8 to 1.2.

[0097] To produce a first diffusion barrier layer of AlGaN and foreign atoms of silicon and magnesium, silicon and magnesium in the form of SiH₄ and Cp₂Mg can be briefly supplied with the other starting materials for AlGaN growth during epitaxy, for example, after the growth of the last quantum film layer 41, in order to grow a co-doped first diffusion barrier layer 6. Subsequently, SiH₄ can be switched off, and, depending on one possible implementation, the growth of a p-doped AlGaN layer as an electron-blocking layer 5 can be continued. Advantageously, the magnesium for p-doping can be arranged closer to the photoactive zone 4, which is formed to create a quantum well structure from quantum film layers 41 and barrier layers 42.This allows for higher radiative recombination and thus higher luminosity, while the silicon doping can continue to inhibit the migration of point defects.

[0098] The thickness of the first Df fusion barrier layer 61 can optionally be a maximum of 120 nm, for example a maximum of 100 nm. This means that the electron and hole wave functions hardly change, which positively influences the radiative recombination and thus the luminescence, especially when the optoelectronic component 1 is designed as a light-emitting diode.

[0099] In the embodiments shown in Fig. 3A and Fig. 3B, the first diffusion barrier layer 6 is arranged in the photoactive zone 4. The selected dopant concentration of the foreign atoms can be in the range of 10 in each case. 15 up to 10 20 cm -3 , for example in the range of 10 15 up to 10 18 cm -3, lay .

[0100] In Fig. 3A, at least one of the quantum film layers 41 can represent a first diffusion barrier layer 6. In the example shown, all quantum film layers 41 are configured as a first diffusion barrier layer 6. For this purpose, the semiconductor material of the photoactive zone in the region of the quantum film layers can contain foreign atoms of a certain type. The foreign atoms are, for example, donors for the semiconductor material, such as silicon for AlGaN.

[0101] Figure 3B shows an embodiment in which at least one of the barrier layers 42, or here all of the barrier layers 42, contains foreign atoms and is configured as a diffusion barrier layer. According to this embodiment, the photoactive zone 4 can, on the one hand, have the function of light emission, and on the other hand, it can also act as a diffusion barrier. The advantage of this embodiment is that no additional zone needs to be introduced between the first semiconductor layer 2 and / or the second semiconductor layer 3 and the photoactive zone 4, and thus the charge carrier transport to the photoactive zone 4 is not affected.

[0102] One particular implementation provides that the quantum film layers or barrier layers can contain not just one type of foreign atom, but a first and a second type, introduced in a ratio to each other ranging from 0.8 to 1.2. For example, the first type consists of donors for the semiconductor material, such as silicon for AlGaN, and the second type consists of acceptors for the semiconductor material, such as magnesium for AlGaN. The selected dopant concentration of the first and second types of foreign atoms can each be in the range of 10 15 up to 10 20 cm -3 , for example in the range of 10 15 up to 10 18 cm -3 , lay .

[0103] Another embodiment of an optoelectronic component is shown in Fig. 4. A first heterojunction barrier layer 9 is arranged adjacent to the photoactive zone 4 between the first semiconductor layer 2 and the photoactive zone 4. This layer can be configured such that a heterojunction is formed between the photoactive zone 4 and the first heterojunction barrier layer 9.

[0104] In an advantageous embodiment, the semiconductor material of the photoactive zone 4 is a compound semiconductor material comprising a first, a second, and a third compositional element. According to this embodiment, the first heterojunction barrier layer 9 can be formed as a superlattice composed of superlattice sublayers. For example, each of these superlattice sublayers is formed from a semiconductor material comprising two of the three compositional elements of the compound semiconductor material of the photoactive zone 4.

[0105] Advantageously, the diffusion of point defects and the migration of hydrogen can be prevented or reduced without the need to introduce foreign atoms into the structure.

[0106] For example, the photoactive layer contains AlGaN, and the superlattice sublayers are formed from AIN (aluminum nitride) and GaN (gallium nitride). The superlattice exhibits a periodic sequence of a first type and a second type of superlattice sublayers, with the first type consisting of aluminum nitride and the second type of gallium nitride.

[0107] The thickness is at least one monolayer of these materials, and at least one superlattice sublayer of each of the two materials should be arranged in the first heterojunction barrier layer 9. The superlattice sublayers of the first heterojunction barrier layer 9 have, for example, a thickness in the range of 0.5 nm to 8 nm, for example from 1 nm to 5 nm.

[0108] Between the second semiconductor layer 3 and the photoactive zone 4, a second heterojunction barrier layer 10 can be arranged adjacent to the photoactive zone 4, according to one embodiment. The second heterojunction barrier layer 10 can also be configured as a superlattice composed of superlattice sublayers. For example, the second heterojunction barrier layer 10 can have the same materials as the first heterojunction barrier layer 9. However, other materials can also be used. Furthermore, the thickness of the second heterojunction barrier layer 10 can differ from the thickness of the first heterojunction barrier layer 9 or be the same. The superlattice sublayers of the second heterojunction barrier layer 10, for example, have a thickness in the range of 0.5 nm to 8 nm, or from 1 nm to 5 nm.The total thickness of the first heterojunction barrier layer 91 and the total thickness of the second heterojunction barrier layer 92 are in the range of 2 nm to 1000 nm according to one embodiment, for example in a range of 30 nm to 70 nm, for example in a range of 45 nm to 55 nm.

[0109] The superlattice sublayers for the formation of the superlattice of the first heterotransition barrier layer 9 and the second heterotransition barrier layer 10 are grown, for example, before and after the photoactive zone 4.

[0110] Figure 5 shows a cross-sectional view of an optoelectronic semiconductor device with several first heterojunction barrier layers 9 according to a further embodiment. The first heterojunction barrier layers 9 are arranged in the photoactive zone 4.

[0111] The photoactive zone 4 can be formed from sublayers, in particular from quantum film layers 41 and barrier layers 42, to form a quantum well structure.

[0112] Each of the first heterotransition barrier layers 9 can be arranged and designed such that the heterotransition is formed by a quantum film layer 41 and one of the first heterotransition barrier layers 9 and / or also by one of the barrier layers 42 and one of the first heterotransition barrier layers 9.

[0113] For example, the photoactive zone is formed from AlGaN and the first heterojunction barrier layers 9 are formed from AIN. This advantageously prevents or at least reduces the diffusion of point defects and hydrogen. The thickness of the first heterojunction barrier layers 91 can be in the range of 0.2 nm to 0.8 nm, for example, from 0.5 to 5 nm.

[0114] Figure 6 shows a schematic band model of an optoelectronic device 1, here a light-emitting device, with a first diffusion barrier layer 6 adjacent to the photoactive zone 4. The photoactive zone 4 can be formed from sublayers to create a quantum well structure. The photoactive zone 4 comprises quantum film layers 41 and barrier layers 42. A second semiconductor layer 3, of n-type conductivity, can be arranged on one side of the photoactive zone 4. A first diffusion barrier layer 6 can be adjacent to the photoactive zone 4 on the other side. Furthermore, an electron blocking layer 5 and a first semiconductor layer 2 of p-type conductivity can be arranged on the optoelectronic device 1.

[0115] The band model here features a conduction band edge 21 and a valence band edge 22. Furthermore, a Fermi energy of the donors 31 and a Fermi energy of the acceptors 32 are shown. It is demonstrated that the Fermi energies of the donors 31 and the Fermi energies of the acceptors 32 within the quantum film layers can be arranged relative to the conduction band edges 21 and valence band edges 22, respectively, in such a way as to favor the desired radiative recombination. It is also shown that the Fermi energy of the donors 31 can undergo an energy change at the interface between the photoactive zone 4 and the first diffusion barrier layer 6, even though the conduction band edge 21 does not change at this interface.In this exemplary embodiment, the foreign atoms introduced in the first diffusion barrier layer 6 can thus lead to a change in the Fermi energy of the donors 31 compared to the Fermi energy of the donors 31 in the adjacent section of the photoactive zone 4.

[0116] Figure 7 shows an exemplary embodiment in which a first heterojunction barrier layer 9 is arranged adjacent to the photoactive zone 4. The schematic band model shows the conduction band edge 21, the valence band edge 22, the Fermi energy of the donors 31, and the Fermi energy of the acceptors 32. Here, too, the photoactive zone 4 can be configured to form a quantum well structure from sublayers, wherein the photoactive zone 4 can be formed from quantum film layers 41 and barrier layers 42. In addition, an electron blocking layer 5 and a first semiconductor layer 2 of a p-type conductivity type are arranged on the optoelectronic device 1.

[0117] As this illustration shows, the Fermi energy of the donors 31 can be formed at the interface between the photoactive zone 4 and the first heterojunction barrier layer 9 without any change in energy. The limitation of diffusion can be achieved here by changes in the energies of the conduction band and the valence band.

[0118] Fig. 8 shows an embodiment of an optoelectronic device 11, which includes the optoelectronic component 1 described herein, for example in the form of a light-emitting device. The optoelectronic device 11 is, for example, a UV illumination device or a UV analysis device. Such an optoelectronic device 11 can be used, for example, for water disinfection or surface disinfection, particularly in medicine.

[0119] Although specific embodiments have been illustrated and described herein, those skilled in the art will recognize that the specific embodiments shown and described can be replaced by a multitude of alternative and / or equivalent embodiments without departing from the scope of protection of the invention. The application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, the invention is limited only by the claims and their equivalents.

[0120] REFERENCE MARK LIST

[0121] 1 Optoelectronic component

[0122] 2 First semiconductor layer

[0123] 3 Second semiconductor layer

[0124] 4 Photoactive Zone

[0125] 5-electron blocking layer

[0126] 6 First dif fusion barrier layer

[0127] 7 Second Dif fusion barrier layer

[0128] 8 buffer layer

[0129] 9 First hetero-transition barrier layer

[0130] 10 Second hetero-transition barrier layer

[0131] 11 Optoelectronic device

[0132] 21 Conductor band

[0133] 22 valence band

[0134] 31 Fermi energy of donors

[0135] 32 Fermi energy of the acceptors

[0136] 41 Quantum film layer

[0137] 42 Barrier layer

[0138] 61 Thickness of the first Df fusion barrier layer

[0139] 71 Thickness of the second Df fusion barrier layer

[0140] 91 Thickness of the first heterojunction barrier layer

Claims

REQUIREMENTS 1. Optoelectronic component (1) , comprising • a photoactive zone (4) , • a first semiconductor layer (2) of a first conductivity type, and • a second semiconductor layer (3) of a second conductivity type, wherein in the photoactive zone (4) a first heterojunction barrier layer (9) is formed such that a heterojunction is formed between the first heterojunction barrier layer (9) and the photoactive zone (4), wherein the photoactive zone (4) comprises a first semiconductor material which is formed as a compound semiconductor material having a first, a second and a third composition element, wherein the first heterojunction barrier layer (9) is formed from a second semiconductor material which has two of these composition elements.

2. Optoelectronic device (1) according to claim 1, wherein a potential step is provided between the photoactive zone and the heterojunction barrier layer (9) in a region of 1 meV and 2 eV are generated.

3. Optoelectronic component (1) according to claim 1 or 2, wherein the first heterojunction barrier layer (9) is formed from an intrinsic material.

4. Optoelectronic device (1) according to one of claims 1 to 3, wherein the first heterojunction barrier layer (9) comprises aluminium nitride.

5. Optoelectronic component (1) according to one of the following Proverbs 1 to 4, whereby the photoactive zone (4) is used for training a quantum well structure comprising quantum film layers (41) and barrier layers (42), wherein the first heterojunction barrier layer (9) is arranged between a quantum film layer (41) and a barrier layer (42).

6. Optoelectronic device (1) according to one of claims 1 to 5, wherein the first heterojunction barrier layer (9) is formed as a superlattice from a periodic sequence of superlattice sublayers.

7. Optoelectronic device (1) according to claim 6, wherein the superlattice sublayers have a thickness in a range of 0.5 nm to 8 nm, for example from 1 nm to 5 nm.

8. Optoelectronic device (1) according to claim 6 or 7, wherein the photoactive zone comprises a first semiconductor material which is a compound semiconductor material comprising a first, a second and a third composition element, wherein the superlattice sublayers each comprise two of the composition elements from which the compound semiconductor material is formed.

9. Optoelectronic device (1) according to one of claims 6 to 8, wherein the superlattice has a periodic sequence of a first type and a second type of superlattice sublayers, wherein the first type is formed from aluminium nitride and the second type from gallium nitride.

10. Optoelectronic device (1) according to one of claims 1 to 10, comprising a second heterojunction barrier layer (10) which is arranged between the photoactive zone (4) and the second semiconductor layer (3) are formed and is arranged so that a heterojunction is formed between the second heterojunction barrier layer (3) and the photoactive zone (4).

11. Optoelectronic device (1) according to any one of claims 1 to 10, wherein the thickness of the first heterojunction barrier layer (9) and / or the second heterojunction barrier layer (10) is in a range of 2 nm to 10 nm.

12. Optoelectronic device (1) according to one of claims 1 to 11, wherein the first semiconductor layer (2) is designed as a p-conductivity type and the first heterojunction barrier layer (9) is arranged at the end of the photoactive zone (4) facing the first semiconductor layer (2).

13. Optoelectronic device (11) with the optoelectronic component (1) according to any one of claims 1 to 12, wherein the optoelectronic device (11) is a UV illumination device or a UV analysis device.

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