Growth of Nanowires

Abstract

An apparatus (1) for producing a plurality of nanowires (2). The apparatus (1) comprises a conductive surface (3), a foil (4), a first electrolyte permeable layer (8), and a second electrolyte permeable layer (9) that is more compressible than the first electrolyte permeable layer (8), in the order mentioned above. The foil (4) has a plurality of channels (5) extending from a first side (6) of the foil (4) to a second side (7) of the foil (4) opposite the first side (6). The apparatus (1) further comprises an electrode (10). The apparatus (1) is configured such that nanowires (2) can be grown on the conductive surface (3) by electrolytic deposition of an electrolyte in each of the channels (5) of the foil (4) by applying a voltage between the conductive surface (3) and the electrode (10).

Description

Technical Field

[0001] The present invention relates to the growth of nanowires on a surface.

Background Art

[0002] It is known to grow nanowires on a conductive surface by electrodeposition from an electrolyte. As an example, there is one described in Patent Document 1. In this case, a foil is attached to the surface to be grown. The foil has a continuous flow path, which is called a pore in Patent Document 1. Nanowires can be grown in this flow path. Thereafter, the foil can be removed, for example, by etching, in order to expose the grown nanowires.

[0003] Nanowires can also be used, in particular, to connect components to each other. For this purpose, nanowires are grown on the surface of one or both components. Thereafter, these components are joined such that the nanowires of one component are connected to the surface of the other component, or the nanowires on the surfaces of the two components are connected to each other.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] It is desirable for nanowires to grow uniformly on a surface. For this, the electrolyte needs to be uniformly distributed on the foil. Therefore, according to Patent Document 1, a sponge is provided as a means for supplying the electrolyte. The electrolyte can be distributed on the foil through this sponge.

[0006] The foil can also be pressed against the surface by a sponge. This is aimed at preventing the deposition of materials at undesirable positions between the surface on which the nanowires are grown and the foil. Without such pressing, there is a possibility that materials will accumulate between the surface on which the nanowires are grown and the foil outside the area where the nanowires are intended to be grown. This effect is hereinafter referred to as "lateral growth". When lateral growth is undesirable, it may also be referred to as "parasitic lateral growth". Such lateral growth can be prevented by pressing the foil strongly enough against the surface on which the nanowires are grown. However, in this way, there is a possibility that the pores of the sponge will be clogged or the flow path of the foil will be blocked, resulting in non-uniform growth of the nanowires.

[0007] Despite such problems of lateral growth, it is desirable to press the foil against the surface to be grown when growing nanowires. This allows the nanowires to be grown directly on the surface. If the foil is not placed exactly on the surface on which the nanowires are grown, extra materials will accumulate between the growing surface and the foil. This may cause the nanowires to become unstable. Furthermore, a thickened area formed from the deposited materials is formed at an early stage, which may be called a "bump". Such bumps may form an undesirable large gap between the surfaces of the parts to be connected to each other. Furthermore, such bumps may prevent the parts from being connected to each other at a relatively large distance. Especially in the case of surface-wide contact, the geometric height of the connection, or the overall thickness of the parts to be connected to each other, may be larger than desired. This is particularly important in the case of geometrically difficult modules such as mobile phones, tablets, and TVs.

[0008] Although good results may already have been obtained with the solution in Patent Document 1, even in this case, it is necessary to find a compromise between the uniform growth of the nanowires and the pressing of the foil against the surface to be grown.

[0009] Based on the above prior art, an object of the present invention is to provide a method for growing nanowires, particularly uniformly, particularly with less lateral growth, and particularly stably.

[0010] This object is achieved by the method and apparatus described in the independent claims. Further advantageous configurations are described in the dependent claims. The features detailed in the claims and the description can be combined with each other in any technically significant manner.

Means for Solving the Problems

[0011] According to the present invention, there is provided an apparatus for manufacturing a plurality of nanowires. The apparatus includes a conductive surface, a foil having a plurality of flow paths extending from a first surface of the foil to a second surface opposite to the first surface of the foil, a first electrolyte permeable layer, a second electrolyte permeable layer that is more easily compressed than the first electrolyte permeable layer, and these components are arranged in the above order. The apparatus further has an electrode. The apparatus is configured such that a voltage can be applied between the conductive surface and the electrode to grow nanowires on the conductive surface by electrolytic deposition from an electrolyte in each flow path of the foil.

[0012] According to the above apparatus, a plurality of nanowires can be generated on the conductive surface, particularly by electrolytic deposition growth. The conductive surface may be part of a conductor. When it is intended to manufacture nanowires on a non-conductive object or an object with insufficient conductivity, the surface of the object or a part thereof may be metallized so as to obtain a conductive surface.

[0013] As used herein, the nanowire refers to any object having a shape similar to a wire and a size in the nanometer range. The nanowire may have, for example, a circular, elliptical, or polygonal bottom surface. In particular, the nanowire may have a hexagonal bottom surface. The nanowire is preferably formed from a metal, such as copper. Preferably, all the nanowires are formed from the same material. The nanowire is preferably perpendicular to the surface. In this case, the nanowires are arranged in a lawn-like manner.

[0014] The nanowire preferably has a length in the range of 100 nm [nanometers] to 100 μm [micrometers], particularly in the range of 500 nm to 50 μm. Further, the nanowire preferably has a diameter in the range of 10 to 10,000 nm, particularly in the range of 30 to 4,000 nm. As used herein, the "diameter" refers to the circular base surface, and in the case of a different base surface, a similar definition of the diameter is used. It is particularly preferred that all the nanowires used have the same length and the same diameter.

[0015] Nanowires can be used, in particular, to connect components to each other. For example, nanowires may be grown on the contact surface of a first component and on the contact surface of a second component. In this case, the two contact surfaces are each used as the conductive surface of the device. Subsequently, the two components may be arranged such that the nanowires on the two contact surfaces contact each other. Due to the large surface area of the nanowires, a mechanically stable connection is formed. This results in a connection that is conductive in the case of conductive nanowires, or thermally conductive in the case of thermally conductive nanowires, or both. This connection can be formed at low cost. In particular, the high temperatures required in conventional connection technologies in the electronics industry, such as soldering, are not necessary. This connection can be strengthened by temporarily pressing both components together with high pressure. Alternatively, even when nanowires are grown only on the contact surface of the first of the two components, the components can be connected to each other. When the components are heated together (e.g., at least 90 °C), the nanowires become connected to the contact surface of the second component. In either method, an adhesive may be further used to strengthen the connection.

[0016] The device further comprises a foil having a plurality of flow channels extending from a first surface of the foil to a second surface opposite the first surface of the foil. Each flow channel is continuous and extends within the foil. Each flow channel is arranged and configured in the same way as the nanowires to be grown. By electrodeposition growth, each flow channel can be filled with a material to produce nanowires. After the nanowires are grown, the foil can be removed, for example, by etching. This exposes the nanowires, which may be used, for example, for connecting components to each other.

[0017] The above-described device further includes a first electrolyte permeable layer and a second electrolyte permeable layer. In order to grow each nanowire uniformly, the two electrolyte permeable layers are used together to uniformly distribute the electrolyte on the foil. Also, in order to limit lateral growth and prevent excessive deposition of material between the foil and the conductive surface, the foil may be pressed onto the conductive surface by the two electrolyte permeable layers. By separating the first electrolyte permeable layer and the second electrolyte permeable layer, which is more easily compressed, these advantages can be achieved to a certain extent simultaneously. The first electrolyte permeable layer is less compressible than the second electrolyte permeable layer. As a result, when a force is applied to the second electrolyte permeable layer in the direction of the conductive surface, especially the second electrolyte permeable layer is compressed. In this case, the foil is pressed onto the conductive surface or the lithography layer or both by the first electrolyte permeable layer. This prevents excessive accumulation of material between the foil and the conductive surface. As a result, lateral growth is limited. When the second electrolyte permeable layer is compressed, the electrolyte may not be uniformly supplied from the second electrolyte permeable layer onto the first electrolyte permeable layer. However, since the first electrolyte permeable layer is less compressible than the second electrolyte permeable layer, the first electrolyte permeable layer is not compressed as strongly as the second electrolyte permeable layer. As a result, the pores of the first electrolyte permeable layer are maintained in a more open state than the pores of the second electrolyte permeable layer. The supply of electrolyte from the second electrolyte permeable layer to the first electrolyte permeable layer, which could potentially be non-uniform, is compensated for thereby. As a result, the electrolyte is uniformly supplied from the first electrolyte permeable layer onto the foil, and each nanowire can be uniformly grown within each flow path of the foil. The above-described device has two electrolyte permeable layers with different properties. The device may also have three or more electrolyte permeable layers. This enables a more detailed functional distribution in each individual electrolyte permeable layer, and accordingly, the above advantages can be more achieved.

[0018] The foil can be pressed against the conductive surface by the first electrolyte permeable layer and the second electrolyte permeable layer. By pressing in this way, the electrolyte can be supplied from the second electrolyte permeable layer to the first electrolyte permeable layer, and the electrolyte can also be supplied from the first electrolyte permeable layer to the foil. When there is only one electrolyte permeable layer, by making it easier to compress, the supply of the electrolyte by pressing may be enabled. In this case, the electrolyte permeable layer as a spring system can fill in the local unevenness on the surface for growing the nanowires, on the foil, or both, and further ensure that the foil is uniformly pressed on the surface for growth over the entire surface for growth. However, in this method, as the applied force increases, the density of the electrolyte permeable layer increases, and as a result, a zone where the electrolyte is difficult to access is formed inside the electrolyte permeable layer. For this reason, there is a possibility that the electrolyte is locally depleted during the growth of the nanowires. Thereby, the nanowires may grow non-uniformly. Furthermore, there is a possibility that the pores of the electrolyte permeable layer are clogged or the flow path of the foil is blocked.

[0019] Alternatively, the electrolyte permeable layer may be one that is easily compressible to the extent that the above-mentioned drawbacks do not occur. In this case, the microvoids of the electrolyte permeable layer can be kept constant even when the applied force increases. Thereby, mixing the electrolyte within the electrolyte permeable layer can be well achieved over a wide range of the applied force. However, the drawback of the electrolyte permeable layer that is difficult to compress is that it cannot sufficiently fill in the unevenness of the surface for growing the nanowires, the foil, or both. Therefore, on the surface for growth, there may exist a zone where the foil is quite firmly pressed on the surface for growth and a zone where a gap still remains between the surface and the foil.

[0020] With the above-described device, the aforementioned drawbacks can be overcome. By combining the two electrolyte permeable layers, on the one hand, a spring effect can be achieved to fill in the unevenness. On the other hand, even when the applied force is large, clogging of the flow path of the foil can be prevented, and good maintenance of the mixing of the electrolyte can be achieved. This is because the electrolyte can first be roughly spread by the second electrolyte permeable layer, and can be supplied by pressing the second electrolyte permeable layer onto the first electrolyte permeable layer. And in the first electrolyte permeable layer, even if there is a slight spread, it can be configured to be able to supply the electrolyte well despite being difficult to compress. In the first electrolyte permeable layer that is difficult to compress, the state where the pores are open can be more easily maintained.

[0021] The first electrolyte permeable layer preferably has a negligible compressibility, and may also be referred to as incompressible. Here, it should be understood that this means that the first electrolyte permeable layer is not significantly compressed by the force that usually occurs during the operation of the device.

[0022] The first electrolyte permeable layer and the second electrolyte permeable layer are permeable to the electrolyte. This is not limited to a specific direction. In particular, the electrolyte can not only permeate in a direction perpendicular to the conductive surface through the first electrolyte permeable layer and the second electrolyte permeable layer, but also move parallel to the conductive surface inside the first electrolyte permeable layer or inside the second electrolyte permeable layer. Therefore, the electrolyte can spread parallel to the conductive surface by the first electrolyte permeable layer and the second electrolyte permeable layer. This enables each nanowire to grow particularly uniformly. The first electrolyte permeable layer and the second electrolyte permeable layer are preferably porous, which can also be said that the first electrolyte permeable layer and the second electrolyte permeable layer originally have an open structure.

[0023] The first electrolyte permeable layer and the second electrolyte permeable layer are preferably porous. In that case, these layers may be referred to as the first porous layer and the second porous layer. Here, "porous" means that the first electrolyte permeable layer and the second electrolyte permeable layer are porous and can permeate the electrolyte.

[0024] The first electrolyte permeable layer and / or the second electrolyte permeable layer may each be formed as a fabric.

[0025] The foil is preferably configured to be permeable to the electrolyte only in a direction perpendicular to the foil. Thus, the electrolyte cannot move parallel to the conductive surface through the foil. Thereby, the foil is particularly different from the first electrolyte permeable layer and the second electrolyte permeable layer. Thus, the foil is not porous in the sense of the term used here. To emphasize this, the flow channels of the foil are not referred to as pores here. Each flow channel of the foil is preferably not branched. Each flow channel is preferably separated from each other. Thus, each flow channel does not form a network of flow channels that branch or connect to each other.

[0026] This device further has an electrode. This device preferably further has a voltage source, which is connected on the one hand to the conductive surface and on the other hand to the electrode. By this voltage source, a voltage can be applied between the conductive surface and the electrode to grow each nanowire.

[0027] Each component of this device is arranged in the order of the conductive surface, the foil, the first electrolyte permeable layer, and the second electrolyte permeable layer. The electrode preferably follows the second electrolyte permeable layer in this order.

[0028] The electrode is preferably located on the second electrolyte permeable layer. However, for example, it is also conceivable to provide an intermediate layer between the electrode and the second electrolyte permeable layer, and in this case, it can be provided, for example, in the form of a further electrolyte permeable layer. The second electrolyte permeable layer is preferably located on the first electrolyte permeable layer. However, for example, it is also conceivable to provide an intermediate layer between the second electrolyte permeable layer and the first electrolyte permeable layer, and in this case, it can be provided, for example, in the form of a further electrolyte permeable layer. The first electrolyte permeable layer is preferably located on the foil. However, for example, it is also conceivable to provide an intermediate layer between the first electrolyte permeable layer and the foil, and in this case, it can be provided, for example, in the form of a further electrolyte permeable layer. In any case, "located" means that there is direct contact between the respective components.

[0029] The foil may be located on a conductive surface. However, this is not essential. This particularly applies when the conductive surface is formed in the recess of the lithography layer. In that case, the foil is preferably located on the lithography layer. Depending on the configuration of the lithography layer and the conductive surface, there may be a space formed between the conductive surface and the foil. During the growth of the nanowire, this empty space is filled with the material of the nanowire. The flow channels of the foil are filled with that material later.

[0030] The conductive surface, the foil, the first electrolyte permeable layer, and the second electrolyte permeable layer preferably form a layer structure. The direction perpendicular to the conductive surface may be referred to as the stacking direction. The foil, the first electrolyte permeable layer, and the second electrolyte permeable layer are preferably formed perpendicular to the stacking direction respectively. This particularly applies to a suitable case where the foil is layered. Also, the electrode is preferably part of the layer structure. Also, the electrode is preferably configured as a layer and particularly formed perpendicular to the stacking direction.

[0031] The above-described apparatus is configured to grow nanowires on a conductive surface by applying a voltage between the conductive surface and an electrode to electrochemically deposit an electrolyte within each flow path of the foil. By supplying an electrolyte, nanowires can be grown. This electrolyte is preferably a liquid capable of electrochemically depositing the material of the nanowires. During the growth of the nanowires, the electrolyte is arranged such that both the electrode and the conductive surface are in contact with the electrolyte and are connected to each other through the electrolyte. This is made possible, in particular, by filling each flow path of the foil, each pore of the first electrolyte permeable layer, and each pore of the second electrolyte permeable layer with the electrolyte. For example, the electrolyte may be introduced into the second electrolyte permeable layer and spread over each flow path of the foil by the second electrolyte permeable layer and the first electrolyte permeable layer. The above-described apparatus may, for example, include a chamber for the electrolyte. This chamber is filled with the electrolyte while the nanowires are growing.

[0032] According to the above-described apparatus, nanowires can be provided over a large area of the substrate. However, the above-described apparatus is also particularly suitable for growing nanowires on a structured substrate. For example, the surface of the substrate can be structured by lithography means such that nanowires grow only within the recesses of the lithography layer. In the above-described apparatus, since the lateral growth can be particularly significantly restricted, a plurality of regions having nanowires can be arranged particularly closely to each other without causing electrical contact between adjacent regions having nanowires. For example, each conductive pad has a small distance from each other and is electrically insulated from each other, but it is possible to grow nanowires on these conductive pads without causing lateral growth that shorts between the conductive pads. Therefore, it is possible to grow nanowires for the purpose of connecting components having a plurality of electrical contacts to each other by the above-described apparatus. A large number of conductive connections separated from each other can be formed between two components by each conductive pad on which nanowires have been grown, and these conductive connections simultaneously connect the components to each other mechanically strongly or thermally conductively or both.

[0033] In one preferred embodiment of the present device, the first electrolyte permeable layer and the second electrolyte permeable layer are configured to be porous, and the second electrolyte permeable layer has a larger average pore diameter than the first electrolyte permeable layer.

[0034] In this embodiment, the second electrolyte permeable layer is a coarser porous than the first electrolyte permeable layer. As a result, the second electrolyte permeable layer has a relatively large average pore diameter. Therefore, the second electrolyte permeable layer has high permeability to the electrolyte, and thus the electrolyte can spread particularly well. However, when the second electrolyte permeable layer is directly located on the foil, a large pore diameter is disadvantageous. When the second electrolyte permeable layer is pressed onto the foil, some of the plurality of flow paths of the foil may be blocked by the material of the second electrolyte permeable layer. To prevent this, the first electrolyte permeable layer is provided. Since its pores are smaller, it is more likely that the electrolyte is actually supplied to each flow path through one of the pores of the first electrolyte permeable layer. This also contributes to the fact that the first electrolyte permeable layer is less likely to be compressed than the second electrolyte permeable layer. Therefore, even when a relatively large pressing force is applied, the pores of the first electrolyte permeable layer remain open.

[0035] In the uncompressed state, it is preferable that the first electrolyte permeable layer has a large number of pore openings on its surface such that, on average, a plurality of pore openings exist within a region having the size of the cross-sectional area of one flow path of the foil. Therefore, each flow path may be supplied with the electrolyte through a plurality of pore openings.

[0036] The second electrolyte permeable layer preferably has an average pore diameter 1 to 20 times larger than that of the first electrolyte permeable layer. The second electrolyte permeable layer preferably has 1 to 20 times more pores than the first electrolyte permeable layer.

[0037] Each pore of the second electrolyte permeable layer is preferably in the range of 30 to 400 nm, particularly in the range of 100 to 220 nm.

[0038] In another preferred embodiment of the present device, in the uncompressed state, the second electrolyte permeable layer extends longer than the first electrolyte permeable layer in a direction perpendicular to the conductive surface.

[0039] Thereby, in the stacking direction, the uncompressed second electrolyte permeable layer has a larger spread than the uncompressed first electrolyte permeable layer. This can also mean that the second electrolyte permeable layer is thicker than the first electrolyte permeable layer when both are uncompressed. The second electrolyte permeable layer extends 2 to 20 times longer than the first electrolyte permeable layer in a direction perpendicular to the conductive surface in the uncompressed state.

[0040] It has been found that by dividing between the first electrolyte permeable layer and the second electrolyte permeable layer as described above, the best results are obtained regarding the growth uniformity of each nanowire and the limitation of lateral growth. Since the second electrolyte permeable layer is relatively large, it can be sufficiently compressed. The first electrolyte permeable layer, which is difficult to compress, does not need to be made larger to fulfill its function. This is because, particularly in the first electrolyte permeable layer, it is sufficient for the electrolyte to spread finely.

[0041] In another preferred embodiment of the present device, the first electrolyte permeable layer is formed of cellulose.

[0042] It has been found that cellulose is a particularly suitable material for the first electrolyte permeable layer. Therefore, it is preferable that the first electrolyte permeable layer is formed only of cellulose. However, the above advantages have already been achieved by the first electrolyte permeable layer having a certain proportion of cellulose. Preferably, at least 50% of the first electrolyte permeable layer is formed of cellulose.

[0043] In another preferred embodiment of the present device, the second electrolyte permeable layer is a sponge.

[0044] In another preferred embodiment, the device further comprises a pressing device for generating a force in the direction of the conductive surface in the second electrolyte permeable layer.

[0045] The pressing device preferably includes a plunger. By using this pressing device, the layer of the above-described layer structure can be compressed. Thereby, in particular, it becomes possible to press the foil onto a conductive surface or, for example, onto a lithography layer. Therefore, it is possible to prevent lateral growth. When the electrode is located on the second electrolyte permeable layer, the plunger preferably engages with the electrode. The electrode may be part of the plunger.

[0046] Instead of the pressing device, the second electrolyte permeable layer can also be pressed manually, for example, in the direction of the conductive surface.

[0047] In another preferred embodiment, the device further includes a substrate having a lithography layer, the lithography layer has one or more recesses, and the conductive surface is formed within one recess or a plurality of recesses.

[0048] This lithography layer is preferably located on the substrate. The foil is preferably located on the lithography layer. The conductive surface for growing the nanowires is formed in one recess or a plurality of recesses of the lithography layer. The substrate is preferably a semiconductor substrate made of, for example, silicon. This substrate may be configured as a wafer. In order to obtain a conductive surface, the substrate may be metallized in one recess or a plurality of recesses of the lithography layer. Thereby, the growth of the nanowires can be locally restricted. When the substrate itself already has conductivity, the substrate surface of one recess or a plurality of recesses of the lithography layer itself can be regarded as the conductive surface for growing the nanowires. The lithography layer preferably has a size in the range of 0.1 to 10 μm [micrometer] in a direction perpendicular to the conductive surface.

[0049] In particular, in this embodiment, a space may be formed between the conductive surface and the foil. During the growth of the nanowires, this empty space is filled with the material of the nanowires, and then the nanowires also grow into each flow path of the foil.

[0050] The lithography layer preferably has a plurality of recesses. The recesses are preferably arranged regularly. In this case, the pitch is preferably within the range of 1 to 10 μm [micrometers]. The pitch referred to here means the center-to-center distance between adjacent recesses.

[0051] As a further aspect of the present invention, a method for manufacturing a plurality of nanowires using the apparatus configured as described above has been proposed. In this method, a voltage is applied between the conductive surface and the electrode, and electrolytic deposition is carried out from the electrolyte in each flow path of the foil, whereby the nanowires are grown on the conductive surface.

[0052] The aforementioned advantages and features of the present apparatus are applicable and transferable to the present method, and vice versa. The present apparatus is preferably configured to operate according to the present method.

[0053] In one preferred embodiment of the present method, the second electrolyte permeable layer is at least temporarily pressed in the direction of the conductive surface.

[0054] Hereinafter, the present invention will be described in more detail with reference to the drawings. The drawings show preferred exemplary embodiments, but the present invention is not limited thereto. The drawings and the ratios of the illustrated sizes are only schematic.

Brief Description of the Drawings

[0055]

Figure 1

Modes for Carrying Out the Invention

[0056] FIG. 1 shows an apparatus 1 for manufacturing a plurality of nanowires 2. This device 1 includes a substrate 12 having a lithography layer 13. The lithography layer 13 has recesses 14 in which a metallization layer 15 is formed. By the lithography layer 13, the metallization layer 15 is limited to the recesses 14 and does not extend over the entire substrate 12. On the side of the metallization layer 15 which is the upper side in FIG. 1, a conductive surface marked with reference numeral 3 is formed. Nanowires 2 can be grown on this conductive surface 3. By the lithography layer 13, the growth of the nanowires 2 is limited to the region of the recesses 14.

[0057] This device 1 further includes a foil 4 having a plurality of flow channels 5. Each flow channel 5 extends from a first surface 6 of the foil 4 to a second surface 7 opposite to the first surface 6 of the foil 4. The foil 4 is located on the lithography layer 13. The foil 4 may be located on the metallization layer 15 in the recesses 14, but this is not essential. In the example of FIG. 1, the foil 4 is shown spaced from the metallization layer 15. This spacing is schematically shown relatively large for the purpose of illustration. In reality, it is in principle possible for the foil 4 and the metallization layer 15 to overlap each other. However, they do not overlap very precisely, and during the growth of each nanowire 2 between the foil 4 and the metallization layer 15, material can actually be locally electrodeposited between the foil 4 and the conductive surface 3.

[0058] The above device 1 further includes a first electrolyte permeable layer 8 located on the foil 4 and a second electrolyte permeable layer 9 located on the first electrolyte permeable layer 8. The first electrolyte permeable layer 8 and the second electrolyte permeable layer 9 are configured to be porous. The second electrolyte permeable layer 9 is more easily compressed than the first electrolyte permeable layer 8, has a larger average pore diameter than the first electrolyte permeable layer 8, and extends longer than the first electrolyte permeable layer 8 in a direction perpendicular to the conductive surface. The first electrolyte permeable layer 8 is formed from cellulose. The second electrolyte permeable layer 9 is a sponge.

[0059] The above-described device 1 further includes an electrode 10 located on the second electrolyte permeable layer 9. The device 1 further has a plunger as a pressing device 11 for generating a force in the direction of the conductive surface 3 on the second electrolyte permeable layer 9. In the illustrated embodiment, the pressing device 11 is located on the electrode 10 and can apply a force in the direction of the conductive surface 3 to the second electrolyte permeable layer 9 through the electrode 10. Due to this force, the foil 4, the first electrolyte permeable layer 8, and the second electrolyte permeable layer 9 are compressed between the lithography layer 13 or the conductive surface 3 and the electrode 10.

[0060] The above-described device 1 is configured such that a voltage can be applied between the conductive surface 3 and the electrode 10 to cause electrolytic deposition of an electrolyte in each flow path 5 of the foil 4, thereby growing the nanowires 2 on the conductive surface 3. This is made possible by the fact that as a result of the electrode 10 and the conductive surface 3 coming into contact with the electrolyte, the electrode 10 and the conductive surface 3 are connected to each other by the electrolyte. For this reason, in particular, each flow path 5 of the foil 4, each pore of the first electrolyte permeable layer 8, and each pore of the second electrolyte permeable layer 9 may be filled with the electrolyte. Then, in the region of the recess 14, the material is electrolytically deposited from the electrolyte onto the conductive surface 3. As shown in the figure, as long as there is a gap between the conductive surface 3 and the foil 4, the filler 16 is first formed, and then each flow path 5 of the foil 4 is filled with the deposited material. The nanowires 2 are composed of this material.

[0061] After the nanowires 2 have grown, the pressing device 11, the electrode 10, the second electrolyte permeable layer 9, and the first electrolyte permeable layer 8 can be removed. For example, the foil 4 may be dissolved by etching to expose the nanowires 2. Similarly, the lithography layer 13 can also be chemically removed. As a result, the nanowires 2 will remain on the conductive pads on the substrate 12. These conductive pads are formed by the metallization layer 15 and the filler 16.

[0062] The project of this application has received funding (Grant Agreement No. 830061) from the European Union's research and innovation program "Horizon 2020".

Explanation of Reference Signs

[0063] 1 Device 2 Nanowire 3 Conductive Surface 4 Foil 5 Flow Path 6 First Surface of the Foil 7 Second Surface of the Foil 8 First Electrolyte Permeable Layer 9 Second Electrolyte Permeable Layer 10 Electrode 11 Pressing Device 12 Substrate 13 Lithography Layer 14 Recess 15 Metallized Layer 16 Filler

Claims

1. An apparatus (1) for manufacturing a plurality of nanowires (2), comprising: a conductive surface (3); a foil (4), the foil (4) having a plurality of flow channels (5) extending from a first surface (6) of the foil (4) to a second surface (7) opposite to the first surface (6) of the foil (4); a foil (4); a first electrolyte permeable layer (8); a second electrolyte permeable layer (9) that is more compressible than the first electrolyte permeable layer (8); wherein these components are arranged in the above order, the apparatus (1) further comprising an electrode (10), and the apparatus (1) is configured such that by applying a voltage between the conductive surface (3) and the electrode (10) to cause electrolytic deposition from an electrolyte within each of the flow channels (5) of the foil (4), nanowires (2) can be grown on the conductive surface (3). Apparatus (1).

2. The apparatus (1) according to Claim 1, wherein the first electrolyte permeable layer (8) and the second electrolyte permeable layer (9) are porous, and the second electrolyte permeable layer (9) has a larger average pore diameter than the first electrolyte permeable layer (8). Apparatus (1).

3. The apparatus (1) according to Claim 1 or 2, wherein in an uncompressed state, the second electrolyte permeable layer (9) extends longer than the first electrolyte permeable layer (8) in a direction perpendicular to the conductive surface (3). Apparatus (1).

4. The apparatus (1) according to Claim 1 or 2, wherein the first electrolyte permeable layer (8) is formed of cellulose. Apparatus (1).

5. The apparatus (1) according to Claim 1 or 2, wherein the second electrolyte permeable layer (9) is a sponge. Apparatus (1).

6. The apparatus (1) according to Claim 1 or 2, wherein the apparatus (1) further comprises a pressing device (11) for generating a force in a direction of the conductive surface (3) in the second electrolyte permeable layer (9). Apparatus (1).

7. The apparatus (1) according to Claim 1 or 2, wherein the apparatus (1) further comprises a substrate (12) having a lithography layer (13), the lithography layer (13) having one or more recesses (14), and the conductive surface (3) is formed within the one recess (14) or the plurality of recesses (14). Apparatus (1). ​ A method for manufacturing a plurality of nanowires (2) using the apparatus (1) according to claim 1 or 2, wherein a voltage is applied between the conductive surface (3) and the electrode (10) to electrochemically deposit from an electrolyte in each flow path (5) of the foil (4), thereby growing the nanowires (2) on the conductive surface (3). Method. **Claim 9** A method according to claim 8, wherein the second electrolyte permeable layer (9) is at least temporarily pressed in the direction of the conductive surface (3). Method.

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