Metal-semiconductor contact structure, solar cell and photovoltaic module

Abstract

Metal-semiconductor contact structure, comprising: a doped semiconductor layer (200); a metal electrode (300) in contact with the doped semiconductor layer; and a first conductive region (1a) provided at a contact interface between the doped semiconductor layer and the metal electrode, the first conductive region comprising: a first conductive structure (11), the first conductive structure comprising a plurality of first metal particles (111) distributed in the first conductive region, the first metal particles having a spherical shape and / or an ellipsoidal shape, at least a part of the first conductive structure being in contact with the doped semiconductor layer; a second conductive structure (12), wherein the second conductive structure is radial, at least a part of the second conductive structure is arranged on a surface of the first metal particles, and a radial direction of the second conductive structure is a direction towards the metal electrode, wherein the metal electrode, the first metal particles and the second conductive structure all comprise the same metal element.

Description

Technical FieldThe present invention relates to the field of solar cells and, more particularly, to a metal-semiconductor contact structure, a solar cell and a photovoltaic module.BackgroundIn a solar cell, contact performance between a metal electrode and a doped semiconductor layer has a significant impact on photovoltaic conversion efficiency and other electrical power indicators of the solar cell. The contact position between the metal electrode and the doped semiconductor layer often leads to an apparent carrier recombination phenomenon, a higher current loss, and a limitation of further improvement in photoelectric conversion efficiency and other electrical characteristics of the solar cell.BRIEF DESCRIPTION OF THE INVENTIONTo solve the above-mentioned technical problem, the present invention discloses a metal-semiconductor contact structure comprising:a doped semiconductor layer;a metal electrode in contact with the doped semiconductor layer;a first conductive region provided at a contact surface between the doped semiconductor layer and the metal electrode, the first conductive region comprising:a first conductive structure, the first conductive structure comprising a plurality of first metal particles distributed in the first conductive region, the first metal particles having a spherical shape and / or ellipsoidal shape, at least a portion of the first conductive structure being in contact with the doped semiconductor layer;a second conductive structure, wherein the second conductive structure is radial, at least a part of the second conductive structure is disposed on a surface of the first metal particles, and a radial direction of the second conductive structure is a direction toward the metal electrode,wherein the metal electrode, the first metal particles, and the second conductive structure all have the same metal element.Further, a number ratio between the second conductive structure and the first metal particles is 1:4000 to 1:1.Further, the number ratio between the second conductive structure and the first metal particles is 1:1000 to 1:20.Further, the particle size of the first metal particles is 20 nm to 360 nm.Further, in each 10 μm x 10 μm region of the first conductive region, the number of the first metal particles is 200 to 4000, the number of a part of the first metal particles having a particle size in the range of 100 nm to 360 nm is 100 to 1500, and the number of another part of the first metal particles having a particle size in the range of less than 100 nm is 100 to 2500.Further, the first conductive structure includes second metal particles attached to a surface of the first metal particles, the first metal particles having a particle size of 20 nm to 360 nm, the second metal particles having a particle size of less than 20 nm, the number of the second metal particles on one of the first metal particles is 1 to 50, and the second metal particles have the same metal element as the first metal particles.Further, the size of the second conductive pattern is 0.2 μm to 2 μm.Furthermore, a plurality of second conductive structures are present in each 10 μm×10 μm region of the first conductive region, the number of the second conductive structures being 2 to 450, the number of a part of the second conductive structures having a particle size in the range from 1 μm to 2 μm being 1 to 100, and the number of another part of the second conductive structures having a particle size in the range from less than 1 μm being 1 to 350.Further, the second conductive pattern includes a plurality of strip-shaped first sub-patterns diverging toward the metal electrode, and the number of the first sub-patterns is 2 to 20.Further, each of the first sub-structures is composed of a plurality of second sub-structures, each of the second sub-structures having the shape of wheat grain, and the plurality of second sub-structures are combined with each other to form the first sub-structure in the shape of wheat ears, the second sub-structures having a cross-sectional dimension of 2 nm to 40 nm.Furthermore, a second conductive region is provided at a contact interface between the doped semiconductor layer and the metal electrode, wherein the second conductive region is arranged at an edge of the first conductive region and the second conductive region comprises an unfired passivation layer, and wherein the first conductive structure and / or the second conductive structure is / are provided between the unfired passivation layer and the metal electrode, wherein, when the second conductive region comprises the first conductive structure, a density of the first conductive structure in the second conductive region is less than a density of the first conductive structure in the first conductive region, and wherein, when the second conductive region comprises the second conductive structure, a density of the second conductive structure in the second conductive region is less than a density of the second conductive structure in the first conductive region.Further, the doped semiconductor layer includes a layer among a doped amorphous silicon layer, a doped polycrystalline silicon layer, a doped microcrystalline silicon layer, and a doped crystalline silicon layer; and / or a dopant element in the doped semiconductor layer is an N-type element or a P-type element; and / or the metal element includes a silver element; and / or at least a part of the second conductive structure is disposed on a surface facing the metal electrode of the doped semiconductor layer.According to a second aspect, the present invention provides a solar cell comprising:a silicon substrate;a doped semiconductor layer, the doped semiconductor layer being provided on the silicon substrate;a metal electrode in contact with the doped semiconductor layer;a first conductive region provided at a contact interface between the doped semiconductor layer and the metal electrode, the first conductive region comprising:a first conductive structure, wherein the first conductive structure comprises a plurality of first metal particles distributed in the first conductive region, wherein the first metal particles have a spherical shape and / or ellipsoidal shape, and wherein at least a portion of the first conductive structure is in contact with the doped semiconductor layer;a second conductive structure, wherein the second conductive structure is radial, at least a part of the second conductive structure is disposed on a surface of the first metal particles, and a radial direction of the second conductive structure is a direction toward the metal electrode,wherein the metal electrode, the first metal particles, and the second conductive structure all have the same metal element.Further, a number ratio between the second conductive structure and the first metal particles is 1:4000 to 1:1.Further, the number ratio between the second conductive structure and the first metal particles is 1:1000 to 1:20.Further, the particle size of the first metal particles is 20 nm to 360 nm.Further, in each 10 μm×10 μm region of the first conductive region, the number of the first metal particles is 200 to 4000, the number of a part of the first metal particles having a particle size in the range of 100 nm to 360 nm is 100 to 1500, and the number of another part of the first metal particles having a particle size in the range of less than 100 nm is 100 to 2500.Further, the first conductive structure includes second metal particles attached to a surface of the first metal particles, the first metal particles having a particle size of 20 nm to 360 nm, the second metal particles having a particle size of less than 20 nm, and the number of the second metal particles on one of the first metal particles is 1 to 50, and the second metal particles have the same metal element as the first metal particles.Further, the size of the second conductive pattern is 0.2 μm to 2 μm.Furthermore, in each 10 μm×10 μm region of the first conductive region, a plurality of second conductive structures are present, the number of the second conductive structures being 2 to 450, the number of a part of the second conductive structures having a particle size in the range from 1 μm to 2 μm being 1 to 100, and the number of another part of the second conductive structures having a particle size in the range from less than 1 μm being 1 to 350.Further, the second conductive pattern includes a plurality of strip-shaped first sub-patterns diverging toward the metal electrode, and the number of the first sub-patterns is 2 to 20.Further, each of the first sub-structures is composed of a plurality of second sub-structures, each of the second sub-structures having the shape of wheat grain, and a plurality of the second sub-structures are combined with each other to form the first sub-structure in the shape of wheat ears, the second sub-structure having a cross-sectional dimension of 2 nm to 40 nm.Furthermore, a second conductive region is provided at a contact interface between the doped semiconductor layer and the metal electrode, wherein the second conductive region is arranged at an edge of the first conductive region and the second conductive region comprises an unfired passivation layer, wherein the first conductive structure and / or the second conductive structure is / are provided between the unfired passivation layer and the metal electrode, wherein, when the second conductive region comprises the first conductive structure, a density of the first conductive structure in the second conductive region is less than a density of the first conductive structure in the first conductive region, and wherein, when the second conductive region comprises the second conductive structure, a density of the second conductive structure in the second conductive region is less than a density of the second conductive structure in the first conductive region.Furthermore, the solar cell has a dielectric layer provided between the silicon substrate and the doped semiconductor layer.Furthermore, the solar cell has a passivation layer which is provided on a side of the doped semiconductor layer facing away from the silicon substrate.Further, the doped semiconductor layer includes an N-doped semiconductor layer and a P-doped semiconductor layer, the N-doped semiconductor layer and the P-doped semiconductor layer are arranged in an interdigital arrangement on a back surface of the silicon substrate, and an isolation region is provided between the N-doped semiconductor layer and the P-doped semiconductor layer; and the metal electrode includes a first metal electrode and a second metal electrode, the first metal electrode and the N-doped semiconductor layer are in contact with each other, and the second metal electrode and the P-doped semiconductor layer are in contact with each other.According to a third aspect, the present invention provides a photovoltaic module, wherein the photovoltaic module comprises:the solar cell according to the second aspect, wherein a plurality of the solar cells are connected in series and / or in parallel to obtain a string of solar cells; anda package structure wherein the solar cell string is packaged in the package structure.As compared with the prior art, the present invention has at least the following advantageous effects:The metal-semiconductor contact structure provided in the embodiments of the present invention has an advantage of having a variety of kinds of carrier transport structures and a large number of carrier transport paths, and therefore can improve the carrier transport capability of the metal-semiconductor contact structure, improve contact performance between the doped semiconductor layer and the metal electrode, and improve the photoelectric conversion efficiency of the solar cell.Brief Description of the DrawingsIn order to more clearly describe the technical solutions in embodiments of the present invention, the accompanying drawings for the embodiments will be briefly described below. It is to be understood that the accompanying drawings in the following description show only some embodiments of the present invention, and that other drawings may be derived from these accompanying drawings by a person skilled in the art without any creative efforts. FIG. 1 is a schematic structural diagram of a first solar cell according to an embodiment of the present invention; FIG. 2 is an enlarged schematic view of a structure at A in FIG. 1 ; FIG. 3 is a schematic view illustrating a method for size measurement of first metal particles according to an embodiment of the present invention; FIG. 4 is a schematic view illustrating a method for size measurement of second metal particles according to an embodiment of the present invention; FIG. 5 is a schematic structural diagram of a second conductive structure according to an embodiment of the present invention; FIG. 6 is an enlarged schematic view of a structure at B in FIG. 2 ; FIG. 7 is a schematic structural diagram of a second solar cell according to an embodiment of the present invention; and FIG. 8 shows an SEM diagram on the metal-semiconductor contact structure in a solar cell according to an embodiment of the present invention.Description of the Reference Numerals:100, A silicon substrate; 200, doped semiconductor layer; 201, first doped semiconductor layer; 202, second doped semiconductor layer; 300, metal electrode; 301, first metal electrode; 302, second metal electrode; 400, passivation layer; 401, first passivation layer; 402, second passivation layer; 403, third passivation layer; 500, dielectric layer; 501, first dielectric layer; 502, second dielectric layer; 600, p-type diffusion layer; 700, passivating antireflection layer; 800, light receiving surface metal electrode; 1, metal-semiconductor contact structure; 1a, first conductive region; 111, first metal particles; 112, second metal particles; 12, second conductive region; 121, first substructure; 1211, second substructure; 1b, second conductive region.DETAILED DESCRIPTIONHereinafter, the technical solutions in embodiments of the present invention will be described in more detail with reference to the accompanying drawings of embodiments of the invention. It is to be understood that the described embodiments represent some, but not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on embodiments of the present invention without any creative efforts fall within the scope of the present invention.In the present invention, the orientation and positional relationship indicated by the terms "on", "under", "left", "right", "front", "rear", "upper", "lower", "inner", "outer", "center", "vertical", "horizontal", "transverse", "longitudinal", and the like refer to the orientation or positional relationship illustrated in the drawings. These terms are intended primarily to better describe the present invention and its embodiments, and are not intended to limit the invention to the fact that the stated devices, elements, or components have a particular orientation or must be constructed and operated in a particular orientation.In addition, some of the above-mentioned terms may be used not only to represent an orientation or positional relationship but also have other meanings. For example, the term "on" may also be used in some cases to refer to a particular attachment or connection. The specific meanings of these terms in the present invention can be understood by those skilled in the art depending on the case.Moreover, the terms "installation", "adjustment", "provided with", "connecting", "connected", "enclosing" should be broadly understood. For example, the connection may be a fixed connection, a releasable connection or an integrated construction, or it may be a mechanical connection or an electrical connection, or it may be a direct connection, or it may be an indirect connection via an intermediate element, or it may be an internal communication between two devices, elements or components. The specific meanings of these terms in the present invention can be understood by those skilled in the art depending on the case.Moreover, the terms "first," "second," etc. are used primarily to distinguish various devices, elements, or components (the specific type and construction may be the same or different), rather than to indicate or imply the relative importance or amount of the device, element, or component indicated. Unless otherwise stated, "a plurality" means two or more.In a solar cell, carriers must be transported to a metal electrode through a doped semiconductor layer, so that the contact performance between the doped semiconductor layer and the metal electrode has a very important influence on the photoelectric conversion efficiency and other characteristics of the solar cell.However, the contact position between the doped semiconductor layer and the metal electrode often leads to large-area interfacial damage due to deep ablation of the metal electrode paste, which in turn leads to a substantial recombination loss between the doped semiconductor layer and the metal electrode, which is finally reflected in that it is difficult to further improve the photoelectric conversion efficiency and other characteristics of the solar cell. It is understood that it is necessary to continuously optimize the contact performance between the doped semiconductor layer and the metal electrode in order to improve the contact performance therebetween and promote the further improvement of the photoelectric conversion efficiency of the solar cell.In order to solve the above-mentioned technical problems, embodiments of the present invention provide a metal semiconductor contact structure, a solar cell, and a photovoltaic module, and solve the above-mentioned problems by optimizing a contact performance of the metal semiconductor contact structure and improving its conductivity. Since the metal-semiconductor contact structure of the embodiments of the present invention is applied to a solar cell (in particular, a crystalline silicon solar cell), the metal-semiconductor contact structure therefor will be presented below in the illustration of the solar cell of the embodiments of the present invention, and the metal-semiconductor contact structure therefor will not be described separately.The embodiments of the present invention provide a solar cell with a metal-semiconductor contact structure 1. Reference is now made to FIGS. 1 and 2. FIG. 1 is a schematic structural diagram of a first solar cell according to an embodiment of the present invention, and FIG. 2 is an enlarged schematic view of a structure at A in FIG. 1, the solar cell including:a silicon substrate 100;a doped semiconductor layer 200, the doped semiconductor layer 200 being provided on the silicon substrate 100;a metal electrode 300 in contact with the doped semiconductor layer 200;That is, the mutual contact between the doped semiconductor layer 200 and the metal electrode 300 forms the metal-semiconductor contact structure 1, and the mutual contact between the doped semiconductor layer 200 and the metal electrode 300 is a physical contact, i.e., the doped semiconductor layer 200 and the metal electrode 300 are in direct contact.As illustrated in FIG. 2, in this metal-semiconductor contact structure 1, a first conductive region is provided at a contact interface between the doped semiconductor layer 200 and the metal electrode 300, the first conductive region 1 acomprising:a first conductive structure 11, wherein the first conductive structure 11 comprises a plurality of first metal particles 111 dispersed in the first conductive region 1 a, wherein the first metal particles 111 have a spherical shape and / or ellipsoidal shape, and wherein at least a part of the first conductive structure 11 is in contact with the doped semiconductor layer 200;a second conductive structure 12, wherein the second conductive structure 12 is radial, at least a part of the second conductive structure 12 is disposed on a surface of the first metal particles 111, and a radial direction of the second conductive structure 12 is a direction toward the metal electrode 300,wherein the metal electrode 300, the first metal particles 111, and the second conductive pattern 12 all have the same metal element.For example, when the metal electrode 300 is a silver electrode, the first metal particles 111 are silver particles, and the second conductive structure 12 having a radial shape also contains a silver element, and in particular, the second conductive structure 12 having a radial shape may be formed by crystallization of silver ions after an electrochemical oxidation-reduction reaction.The metal-semiconductor contact structure 1 provided in the embodiments of the present invention has an advantage of having a variety of kinds of carrier transport structures and a large number of carrier transport paths, whereby the carrier transport capability of the metal-semiconductor contact structure 1 can be improved, contact performance between the doped semiconductor layer 200 and the metal electrode 300 can be improved, and photoelectric conversion efficiency of the solar cell can be improved.In the embodiments of the present invention, both the radial second conductive structure 12 and the spherical and / or ellipsoidal first metal particles 111 have a charge transport capability, and more importantly, since at least a part of the second conductive structure 12 is located on the surface of the first metal particles 111, the combination of the second conductive structure 12 and the first metal particles 111 can also be considered as another charge transport structure. Therefore, in the embodiments of the present invention, there are many kinds of structures capable of transporting carriers, which is advantageous for improving the carrier transportability.On the basis of this, the structures described above may provide a plurality of different carrier transport paths and may help to transport carriers from the doped semiconductor layer 200 to the metal electrode 300 more easily and with fewer obstacles.The first carrier transport path includes the silicon substrate 100, the doped semiconductor layer 200, the first metal particles 111, the radial second conductive structure 12, and the metal electrode 300. The photogenerated charge carriers generated in the silicon substrate 100 are transported into the doped semiconductor layer 200, then transported by the first metal particles 111 that are in direct contact with the doped semiconductor layer 200, and subsequently transported to the metal electrode 300 through the radial second conductive structure 12 that is in direct contact with the first metal particles 111. Among them, the first metal particles 111 and the second conductive pattern 12 are both formed of metal and thus have good conductivity. In particular, since the second conductive pattern 12 extends radially and the radial divergence direction faces toward the metal electrode 300, this divergence pattern causes the carrier transport paths to be longer and more numerous and the resistance is lower, so that the carrier transport capacity can be improved more effectively.Here, a second carrier transport path includes the silicon substrate 100, the doped semiconductor layer 200, the radial second conductive structure 12, and the metal electrode 300. With the exception of the portion of the radial second conductive structure 12 which is located on the surface of the first metal particles 111, another portion of the radial second conductive structure 12 is grown directly on the surface of the doped semiconductor layer 200 which faces the metal electrode 300, wherein this portion of the second conductive structure 12 can transport charge carriers directly from the doped semiconductor layer 200 to the metal electrode 300. Moreover, the metal-semiconductor contact structure 1 according to the embodiments of the present invention further includes a third carrier transport path including the silicon substrate 100, the first metal particles 111 dispersed in the first conductive region 1 a, and the metal electrode 300. Although at least some of the first metal particles 111 are not in direct contact with each other, the carriers can pass current through these first metal particles 111 by utilizing an electron tunnel effect.In summary, it can be stated that the metal-semiconductor contact structure 1 of the embodiments of the present invention comprises not only charge carrier transport structures having a wide variety of structure types, but also a multiplicity of charge carrier transport paths. The above-mentioned structural features can improve contact performance between the doped semiconductor layer 200 and the metal electrode 300, reduce transport loss of carriers, and further improve photoelectric conversion efficiency of the solar cell.The conductive structure in the first conductive region 1 ais described in more detail below.The number ratio between the second conductive structure 12 and the first metal particles 111 is 1:4000 to 1:1. for example, the number ratio between the second conductive structure 12 and the first metal particles 111 is 1:4000, 1:3000, 1:2000, 1:1000, 1:800, 1:500, 1:200, 1:100, 1:80, 1:50, 1:20, 1:10 or 1:1.When the number ratio between these two conductive structures is controlled within the above-mentioned range, the open circuit voltage and the contact performance of the solar cell can be more balanced, and occurrence of phenomena such as increasing damage to the doped semiconductor layer 200 or the silicon substrate 100 or increasing contact resistance can be reduced.It is understood that the number ratio between the second conductive structure 12 and the first metal particles 111 can be calculated by measuring the number of the second conductive structure 12 and the number of the first metal particles 111 in any 10 μm×10 μm range. Specifically, 10 μm×10 μm areas may be selected at five different positions, the second conductive structure 12 and the first metal particles 111 may be counted, and the number ratio between the second conductive structure 12 and the first metal particles 111 may be calculated, and the range between the minimum value and the maximum value of the number ratio at these different positions may reflect the number ratio range of the second conductive structure 12 and the first metal particles 111, and the average value of the number ratios at these different positions may reflect the average value of the number ratio between the second conductive structure 12 and the first metal particles 111.Preferably, the number ratio between the second conductive structure 12 and the first metal particles 111 is 1:1000 to 1:20.In the first conductive structure 11, the particle size of the first metal particles 111 is 20 nm to 360 nm. For example, the particle size of the first metal particles 111 is 20 nm, 50 nm, 80 nm, 100 nm, 150 nm, 180 nm, 200 nm, 250 nm, 280 nm, 300 nm, 320 nm or 360 nm.By controlling the particle size of the first metal particles 111 within the above-mentioned range, it is possible to provide an appropriate growth space for the radial second conductive structure 12 and cause the second conductive structure 12 to have a good emission morphology, thereby improving the carrier transport capacity. The disadvantage of the growth of the second conductive structure 12 on the surface of the first metal particles 111 due to too small a particle size, thereby making it difficult for the second conductive structure 12 to grow into a metal structure having apparent emission morphology properties, can be avoided, and the occurrence of a situation in which the second conductive structure 12 is obstructed by too large a particle size can be reduced.Note that the first metal particles 111 may have a spherical shape and / or an ellipsoidal shape, and when the first metal particles 111 have a spherical shape, the size of the first metal particles 111 refers to the diameter of the spherical shape. When the first metal particles 111 have an ellipsoidal shape, the particle size of the first metal particles 111 refers to the longest dimension of the ellipsoid. For example, as shown in FIG. 3, considering an irregular ellipsoid as an example, the ellipsoid has two points furthest from each other along the first direction, and the linear distance d1between these two points is the longest dimension of the ellipsoid, which is also the particle size of the ellipsoid.Further, in each 10 μm×10 μm region of the first conductive region 1 a, the number of the first metal particles 111 is 200 to 4000, the number of the first metal particles 111 having a particle size in the range of 100 nm to 360 nm is 100 to 1500, and the number of the first metal particles 111 having a particle size in the range of less than 100 nm is 100 to 2500.Returning to FIG. 2, the first conductive structure 11 includes, in addition to the above-described first metal particles 111, second metal particles 112 fixed to the surface of the first metal particles 111. The particle size of the second metal particles 112 is less than 20 nm, the number of the second metal particles 112 on one of the first metal particles 111 is 1 to 50, and the second metal particles 112 and the first metal particles 111 have the same metal element.The adhesion of the second metal particles 112 having the aforementioned number and particle size to the first metal particles 111 may further increase the surface area of the first conductive structure 11 and then allow further optimization of the contact performance between the doped semiconductor layer 200 and the metal electrode 300 and a decrease in contact resistance between the doped semiconductor layer 200 and the metal electrode 300.Further, the size of the second conductive pattern 12 is 0.2 μm to 2 μm. For example, the size of the second conductive pattern 12 is 0.2 μm, 0.5 μm, 0.8 μm, 1.0 μm, 1.2 μm, 1.5 μm, 1.8 μm, or 2 μm.As illustrated in FIG. 4, the second conductive pattern 12 is a radial pattern, and the size of the second conductive pattern 12 refers to the width d 2 between the two farthest points from each other where the second conductive pattern 12 diverges and expands outward.When the size of the second conductive pattern 12 is within the above-mentioned range, it is possible to achieve good charge transport capability, reduce the damage area of the contact interface between the doped semiconductor layer 200 and the metal electrode 300, reduce the occurrence of contact recombination, and better optimize the contact performance between the doped semiconductor layer 200 and the metal electrode 300.Further, in each 10 μm×10 μm region of the first conductive region 1 a, the number of the second conductive structures 12 is 1 to 450, the number of the second conductive structures 12 having a particle size in the range of 1 μm to 2 μm is 1 to 100, and the number of the second conductive structures 12 having a particle size in the range of less than 1 μm is 1 to 350.As illustrated in FIG. 5, the second conductive structure 12 includes a plurality of strip-shaped first sub-structures 121 diverging toward the metal electrode 300, and the number of the first sub-structures 121 is 2 to 20.Each of the first sub-structures 121 is composed of a plurality of second sub-structures 1211, each of the second sub-structures 1211 has the shape of a wheat grain, and a plurality of the second sub-structures 1211 are combined with each other to form the first sub-structure 121 in the shape of wheat ears; the second sub-structure 1211 having a cross-sectional dimension of 2 nm to 40 nm.That is, in an embodiment of the present invention, the second conductive structure 12 is formed by a plurality of first sub-structures 121 in the form of wheat ears diverging toward the metal electrode 300, and each of the first sub-structures 121 in the form of wheat ears is formed by a combination of a plurality of second sub-structures 1211 in the form of wheat grains. This particular divergent structural feature enables the second substructure 1211 to have a higher degree of divergence, thereby providing a larger contact area with the metal electrode 300, which is advantageous for further improving charge carrier transport capability.The cross-sectional dimension of the second substructure 1211 is 2 nm to 40 nm, including all point values in this numerical range, for example the cross-sectional dimension of the second substructure 1211 is 2 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm or 40 nm. Moreover, the cross-sectional dimension of the second substructure 1211 refers to the corresponding cross-sectional width of the second substructure 1211 projected onto a horizontal plane of the silicon substrate 100.In addition to the first conductive region 1 a, the metal-semiconductor contact structure 1 of the embodiments of the present invention has a second conductive region 1 bat the contact interface between the doped semiconductor layer 200 and the metal electrode 300, wherein the second conductive region 1 bis arranged at the edge of the first conductive region 1 a. As illustrated in conjunction with FIGS. 2 and 6, the second conductive region 1 bhas an unfired passivation layer 400, and the aforementioned first conductive pattern 11 and the second conductive pattern 12 are provided between the unfired passivation layer 400 and the metal electrode 300. Here, the density of the first conductive pattern 11 in the second conductive region 1 bis lower than the density of the first conductive pattern 11 in the first conductive region 1 a, and the density of the second conductive pattern 12 in the second conductive region 1 bis lower than the density of the second conductive pattern 12 in the first conductive region 1 a.In the metal-semiconductor contact structure 1 according to an embodiment of the present invention, in addition to the first conductive region 1 athat has stronger carrier transport capability in the central region of the contact interface between the doped semiconductor layer 200 and the metal electrode 300, there is a second conductive region 1 bat the edge of the first conductive region 1 a. The second conductive region 1 bis located at a position corresponding to the unfired passivation layer 400, and the first conductive region 1 ais located at a position mainly corresponding to the position at which the passivation layer 400 is blown, so that the doped semiconductor layer 200 is in direct contact with the metal electrode 300. For example, considering the case where the metal electrode 300 is a subgate having a width of 20 μm to 35 μm, the first conductive region 1 ais located in a width range of 18 μm to 33 μm at the center of the gate line, and the second conductive region 1 bis located in a width range of 1 μm to 5 μm at the edge of the gate line.In the second conductive region 1 b, the passivation layer 400 that is not blown may protect the doped semiconductor layer 200 on its inner side and thus serve as passivation protection, thereby further reducing the damage area of the surface of the doped semiconductor layer 200 and reducing contact recombination losses of charge carriers due to damage to the surface structure of the doped semiconductor layer 200. That is, the conductive structure in the first conductive region 1 aarranged in the center has a larger density, its distribution is more concentrated, and thus plays a dominant role in the carrier transport process. At the same time, the passivation layer 400 not burned through in this region can take the role of passivation protection despite the relatively low density of the conductive structure in the second conductive region 1 b, thereby enabling the metal-semiconductor contact structure 1 of the present invention to not only improve the carrier transport capacity by optimizing the conductive structure but also reduce the carrier recombination loss by decreasing the area of the interface where the doped semiconductor layer 200 is damaged by ablation, so as to promote the improvement of the contact performance between the doped semiconductor layer 200 and the metal electrode 300 in two respects, which is finally reflected in an effective improvement of the photoelectric conversion efficiency of the solar cell.Further details of the metal-semiconductor contact structure 1 are described further below.In an embodiment of the present invention, the doped semiconductor layer 200 includes a doped polycrystalline silicon layer, a doped microcrystalline silicon layer, or a doped crystalline silicon layer. For example, when the doped semiconductor layer 200 includes a doped crystalline silicon layer, the doped crystalline silicon layer may be formed by thermal diffusion of a dopant on crystalline silicon. As another example, when the doped semiconductor layer 200 includes a doped polysilicon layer, the doped semiconductor layer 200 may be a doped polysilicon layer doped with a dopant by an LPCVD or PECVD method.The dopant in the doped semiconductor layer 200 is an N-type dopant or a P-type dopant. The N-type dopant includes at least one of phosphorus, antimony, or arsenic, and the P-type dopant includes at least one of boron, indium, or gallium. For example, the doped semiconductor layer 200 is a phosphorus doped semiconductor layer 200, which means that when the main component is a polycrystalline silicon layer, a phosphorus element may be doped therein to improve carrier transport capability, and on this basis, a certain concentration of other kinds of doping elements may also be doped into the phosphorus doped semiconductor layer 200, which is not limited in the present invention.In an embodiment of the present invention, the metal electrode 300 is made of a material corresponding to the metal element as a main component, and may also contain an appropriate amount of impurities. The metal electrode 300, the first metal particles 111, and the second conductive pattern 12 all have the same metal element. For example, the metal electrode 300 is a silver electrode, and the main component of the silver electrode is elemental silver, but the silver electrode may also contain a small amount of aluminum metal impurities (for example, the content of aluminum metal impurities is less than or equal to 0.1 wt %).Moreover, the semiconductor layer 200 may be provided on a light receiving surface and / or a back surface of the silicon substrate 100, and accordingly, the metal semiconductor contact structure 1 may also be provided on the light receiving surface and / or the back surface of the silicon substrate 100. Moreover, the metal-semiconductor contact structure 1 is preferably formed on a relatively planar surface, such as the surface of a polished silicon substrate 100.According to the solar cell illustrated in FIG. 1, the metal-semiconductor contact structure 1 is provided on the back surface of the silicon substrate 100 as an example for further explanation. In an alternative embodiment, the silicon substrate 100 is an N-type silicon substrate 100, wherein a doped semiconductor layer 200, particularly an N-doped polycrystalline silicon layer formed by a method such as LPCVD or PECVD, is provided on the back surface of the silicon substrate 100, and a metal electrode 300 is provided on the N-doped polycrystalline silicon layer in contact therewith. The N-doped polycrystalline silicon layer and the metal electrode 300 constitute the above-mentioned metal-semiconductor contact structure 1, it is understood that the silicon substrate 100 may also be a P-type silicon substrate 100, and the conductivity type of the doped semiconductor layer 200 may be the same as or different from that of the silicon substrate 100, and the present invention does not limit the above-mentioned conductivity type.In addition to the above-described metal-semiconductor contact structure 1, the solar cell can also have other functional layers. For example, the rear surface of the solar cell can also have:a dielectric layer 500 provided on the back surface of the silicon substrate 100 and disposed between the silicon substrate 100 and the doped semiconductor layer 200, wherein the dielectric layer 500 and the doped semiconductor layer 200 form a passivation contact structure to improve carrier transport capability while optimizing passivation performance;a passivation layer 400 provided on the side of the doped semiconductor layer 200 facing away from the silicon substrate 100 for improving the passivation performance.In the metal-semiconductor contact structure 1, after penetrating the passivation layer 400, the metal electrode 300 is in contact with the doped semiconductor layer 200 and forms the first conductive structure 11 and the second conductive structure 12 in the first conductive region 1 a. However, a small portion of the passivation layer 400 is not completely burned through at the edge of the metal electrode 300, and this portion of the passivation layer 400 and the metal electrode 300 form the second conductive region 1 bas described above.The light receiving surface of the solar cell may further include: a P-type diffusion layer 600 provided on the light receiving surface of the silicon substrate 100 and capable of being formed by a thermal diffusion process and used for forming a PN junction with the silicon substrate 100; a passivating antireflection layer 700 provided on the side of the P-type diffusion layer 600 opposite to the silicon substrate 100 and used for passivation and antireflection; a light receiving surface metal electrode 800 penetrating the passivating antireflection layer 700 and in ohmic contact with the P-type diffusion layer 600.Next, the manufacturing process of the above-mentioned solar cell will be explained.With respect to the layers such as the silicon substrate 100 and the doped semiconductor layer 200 and the passivation layer 400, a semi-finished product of the above-mentioned solar cell can be obtained by conventional methods such as texturing, thermal diffusion, chain cleaning, polishing, PECVD, RCA cleaning, and ALD coating. For example, a P-type diffusion layer 600 is formed on the light receiving surface of the silicon substrate 100 by thermal diffusion (specifically, a method such as boron diffusion), unnecessary layers such as a winding plating layer and an oxide layer are removed by methods such as chain cleaning and polishing, and the back surface of the silicon substrate 100 is smoothed; then, a dielectric layer 500 and an N-doped polycrystalline silicon layer are sequentially formed on the back surface of the silicon substrate 100 by a PECVD process; after the unnecessary layers such as a winding plating layer are removed by RCA cleaning, a passivation layer 400 is formed on the N-doped polycrystalline silicon layer by an ALD process; And on the P-type diffusion layer 600, a passivating antireflection layer 700 is formed, thereby obtaining a semi-finished product of the solar cell. Here, the N-doped polysilicon layer is the doped semiconductor layer 200.An electrode paste is printed and sintered on the semi-finished product of the solar cell, and then a laser-induced contact treatment is performed so that the doped semiconductor layer 200 and the metal electrode 300 form the above-described metal-semiconductor contact structure 1. The specific method is as follows:printing an electrode paste on the passivation layer 400 on the doped semiconductor layer 200, the electrode paste including a glass phase material, a metal material, and an organic carrier, and the metal material including the above-mentioned metal element;pre-sintering the electrode paste to form an electrode precursor;performing laser-induced contact treatment from the side of the silicon substrate 100 facing away from the electrode precursor (i.e., the light receiving surface of the silicon substrate 100), so that the electrode precursor constitutes a metal electrode 300 and the metal electrode 300 and the doped semiconductor layer 200 constitute a metal-semiconductor contact structure 1.By printing and sintering the electrode paste on the passivation layer 400 on the back surface of the silicon substrate 100 and in cooperation with the laser-induced contact treatment with respect to the light receiving surface of the silicon substrate 100, after the laser energy has passed through the silicon substrate 100 to the back surface side, the metal-semiconductor contact structure 1 having the above-mentioned structural features can be formed.Further, in the electrode paste pre-sintering step, the total sintering time is 40 s to 100 s, and the sintering time corresponding to the condition of a sintering temperature of 700° C. to 800° C. is 0.5 s to 8 s. In comparison with the conventional high-temperature pre-sintering process, the embodiments of the present invention do not cause large-area corrosion on the surface of the silicon-based doped semiconductor layer despite such a high-temperature pre-sintering condition.Further, in the step of performing the laser-induced contact treatment from the side of the silicon substrate 100 opposite to the electrode precursor, a voltage value of the blocking voltage is 8 V to 14 V. The heat generated by the carriers generated by the laser-induced contact treatment when passing through the contact interface between the first silicon-based doped semiconductor layer and the electrode precursor is closely related to the above-mentioned range of the blocking voltage. When the blocking voltage is within the above-mentioned range, this promotes generation of a higher heat when the carriers pass the contact interface, and this higher heat is used to decompose the glass phase material at the respective positions, so as to provide a space for the growth and formation of the first conductive structure 11 and the second conductive structure 12.Further, the conditions of the laser-induced contact treatment in the step of performing the laser-induced contact treatment include a single wavelength spectrum having a wavelength of 500 nm to 1100 nm, a current density of 800 A / cm 2 to 1300 A / cm 2 and a scan rate of 32 m / s to 50 m / s.For the aforementioned conditions of laser-induced contact treatment, a laser having a single wavelength is used to excite photogenerated charge carriers in the doped semiconductor layer 200. For example, the wavelength of the injected laser light in the process of laser-induced contact treatment is 532 nm, 635 nm, 650 nm, 808 nm, 980 nm or 1064 nm. When the semiconductor element of the doped semiconductor layer 200 is silicon and a laser is used for the laser-induced contact treatment, it is advantageous to use a laser having a wavelength of 1064 nm or 808 nm.Preferably, the manufacturing method of the metal-semiconductor contact structure 1 further comprises: performing a light injection after the step of pre-sintering the electrode paste and before the step of performing the laser-induced contact treatment with respect to the side of the silicon substrate 100 facing away from the electrode precursor. The light injection process mainly serves to improve the passivation performance. The process steps of the light injection annealing furnace include: a first heating step in which H atoms in the silicon nitride passivation layer are activated by the heating; a second step of controlling the valence state of H atoms by light irradiation so that the H atoms combine with recombination centers (defects) at the P+emitter and the N-type substrate to form non-recombination centers. Finally, a good passivation effect is achieved and the aim of improving the open circuit voltage and the fill factor is achieved.Moreover, as compared with a method in which the light injection is performed after the step of performing the laser-induced contact treatment, a method in which first the electrode paste is pre-sintered at a high temperature, then the light injection is performed, and then the laser-induced contact treatment is performed with respect to the electrode precursor is more advantageous in optimizing the performance of the solar cell. This is because the process of light injection also generates a certain amount of heat, and when light injection is performed before laser-induced contact treatment, grain boundaries and defect states can be passivated.Moreover, the light injection process adjusts the Fermi level change by temperature and light intensity and controls the total amount of hydrogen and the valence state to improve passivation performance. Further, the light injection step includes: primarily heating the electrode precursor, wherein a peak temperature of the primary heating is between 180° C. and 620° C.; secondarily heating the electrode precursor and light irradiation, wherein a peak temperature of the secondary heating is 80° C. to 320° C., an energy density of the light irradiation is 12 kW / m 2 to 120 kW / m 2 and the wavelength of the light irradiation is a continuous spectral band of 500 nm to 1100 nm. By controlling the heating conditions and the light irradiation conditions within the above-mentioned range in the light injection step, not only can a good passivation effect be obtained, but also the glass phase material that corrodes the first doped silicon-based semiconductor layer due to too high a heating temperature can be prevented. Note that in the light injection step of the embodiment of the present invention, a continuous spectral band having a wavelength of 500 nm to 1100 nm is injected, which is different from the single wavelength laser used in the laser-induced contact treatment step.It is to be noted that the above-mentioned solar cell manufacturing method is merely an alternative implementation and the metal-semiconductor contact structure 1 in the embodiments of the present invention may also be obtained by other conventional processing techniques and is not limited in the present invention.The above-described metal-semiconductor contact structure 1 is also suitable for use in other types of solar cells. According to FIG. 7, a solar cell of a second type is therefore provided by the embodiments of the present invention, wherein the solar cell is an IBC solar cell and the solar cell comprises:a silicon substrate 100;a first dielectric layer 501, a first doped semiconductor layer 201 and a first passivation layer 401 provided sequentially in an N-type conductive region of a back surface of the silicon substrate 100, and a second dielectric layer 502, a second doped semiconductor layer 202 and a second passivation layer 402 provided sequentially in a P-type conductive region of the back surface of the silicon substrate 100, wherein the first doped semiconductor layer 201 is doped with an N-type dopant and the second doped semiconductor layer 202 is doped with a P-type dopant;a first metal electrode 301 penetrating the first N-type conductive region passivation layer 401 and forming ohmic contact with the first doped semiconductor layer 201, so that the first metal electrode 301 and the first doped semiconductor layer 201 form a first metal-semiconductor contact structure 1;a second metal electrode 302 penetrating the second P-type conductive region passivation layer 402 and forming an ohmic contact with the second doped semiconductor layer 202, so that the second metal electrode 302 and the second doped semiconductor layer 202 form a second metal-semiconductor contact structure 1.That is, in the second type solar cell, the doped semiconductor layer 200 includes a first doped semiconductor layer 201 and a second doped semiconductor layer 202 having different conductivity types, and the metal electrode 300 includes a first metal electrode 301 and a second metal electrode 302 that are in contact with the first doped semiconductor layer 201 and the second doped semiconductor layer 202, respectively, to form the above-described metal-semiconductor contact structure 1.The silicon substrate 100 has an N-type conductivity or a P-type conductivity, for example, the silicon substrate 100 is an N-type silicon substrate 100. A light receiving surface of the silicon substrate 100 has a textured surface structure, for example, a pyramidal textured surface structure. By providing the textured surface structure, the reflectivity of the surface of the silicon substrate 100 is advantageously reduced and the light trapping effect of the light within the silicon substrate 100 is increased. In addition, other pattern layers may be provided on the light receiving surface of the silicon substrate 100 according to actual requirements. For example, a third passivation layer 403 is provided on the light receiving surface of the silicon substrate 100.Further, embodiments of the present invention provide a photovoltaic module including the solar cell according to the first aspect and a packaging structure, wherein a plurality of solar cells are connected in n series and / or in parallel to obtain a solar cell string, and wherein the solar cell string is packaged in the packaging structure to form the above-mentioned photovoltaic module.The present invention will be explained below in more detail with reference to specific examples.Embodiment 1The present embodiment provides a solar cell including:an N-type silicon substrate;a P-type diffusion layer, a passivating antireflection layer and a light receiving surface metal electrode provided sequentially on the light receiving surface of the N-type silicon substrate, the light receiving surface metal electrode penetrating the passivating antireflection layer and being in ohmic contact with the P-type diffusion layer;a dielectric layer, an N-doped polysilicon layer, a passivation layer and a back surface metal electrode sequentially provided on the back surface of the N-type silicon substrate, the back surface metal electrode penetrating the passivation layer and being in contact with the N-doped polysilicon layer.A first conductive region is provided at the contact interface between the N-doped polycrystalline silicon layer and the metal electrode of the back surface, the first conductive region comprising:a first conductive structure, the first conductive structure comprising a plurality of first metal particles distributed in the first conductive region, the first metal particles having a spherical shape and / or ellipsoidal shape, at least a portion of the first conductive structure being in contact with the doped semiconductor layer;a second conductive structure 12, wherein the second conductive structure 12 is radial, at least a part of the second conductive structure 12 is disposed on a surface of the first metal particles, and a radial direction of the second conductive structure 12 is a direction toward the metal electrode,wherein the metal electrode, the first metal particles, and the second conductive structure all have the same silver element.The particle size of the first metal particles is 20 nm to 360 nm, the particle size of the second metal particles is less than 20 nm, the size of the second conductive structure is 0.2 μm to 2 μm, and the number ratio between the second conductive structure and the first metal particles is 1:4000. In this embodiment, the relationship between the number of second conductive structures and the number of first metal particles can be obtained by measuring the number of corresponding structures in the first conductive region at different positions of any 10 μm×10 μm region and calculating the number of corresponding structures and then averaging them.With respect to the above-described metal-semiconductor contact structure, a scanning electron microscopy (SEM) test was carried out (see:. FIG. 8 for an SEM image). The scanning electron microscopy test method for the metal-semiconductor contact structure is described below:Using a chemical etching apparatus, first, a nitric acid solution having a mass ratio of 50% to 80% is heated to 60° C. to 85° C., then the solar cell is immersed in the above-mentioned nitric acid solution for 3 to 10 minutes, and the metal electrode is removed; the residual liquid is rinsed out using deionized water or distilled water; then the purified solar cell is immersed in a hydrofluoric acid solution having a mass ratio of 1% to 10% to remove the residual glass phase material for 2 to 5 minutes; finally, the residual liquid is rinsed out using deionized water or distilled water, and corrosion is completed. The conductive patterns of the first conductive region and the second conductive region in the metal-semiconductor contact structure were exposed and photographed by a scanning electron microscope to obtain respective SEM charts. It is understood that the concentration of the acid, the etching temperature and the etching time used in the aforementioned etching apparatus can be adjusted according to the removal efficiency as long as the metal electrode and the glass phase material can be removed. For example, as the concentration of the acid and / or temperature increases, the etch time may be shortened as necessary to achieve better removal of the metal electrode and glass phase material.Embodiments 2 to 7These embodiments were identical to Embodiment 1 except that the number ratio between the second conductive structure and the first metal particles is as shown in Table 1.Description of the Performance Test:Testing of open circuit voltage, fill factor and photoelectric conversion efficiency:The tests for open circuit voltage, fill factor, photoelectric conversion efficiency and other performance tests were carried out using a Halm test and a separator. The Halm machine was a solar simulator equipped with an electronic load, data acquisition and computing devices to test the electrical performance of photovoltaic devices (including solar cells). The silicon wafer of the solar cell tested was set to size 182 and the calibrated light intensity was 1000±5 W / m 2.Contact resistance test: For the contact resistance performance test, a contact resistance tester (e.g., TLM-STD of American Photovoltaic) was used, and the characteristic impedance of the transmission line was determined by measuring the current and the voltage, and then the value of the contact resistance was derived from a calculation formula according to the characteristic impedance. The width of the test piece was 6 mm. Table 1 Number ratio of the conductive structures and results of the battery performance tests of the embodiments Table 1 Number ratio of the conductive structures and results of the battery performance tests of the embodimentsEmbodiment 11:400024,9390,729382,401,12Embodiment 21:50025,1140,729082,911,07Embodiment 31:10025,0950,728982,961,08Embodiment 41:2525,1140,729682,951,05Embodiment 51:125,0610,728782,881,05Embodiment 61:1000024,8940,730682,111,22Embodiment 72:124,8090,720882,931,01From the test results in Table 1, it can be seen that in the solar cells of Embodiments 1 to 5 of the present invention, the series resistance decreases to about 1.00 mΩ·cm 2 and the photoelectric conversion efficiency reaches about 25.1%. It is understood that the solar cells of Embodiments 1 to 5 of the present invention all have excellent open-circuit voltage and series resistance performance, and have relatively high photoelectric conversion efficiency. From this, it can be seen that 1:4000 to 1:1 is a preferable range for the number ratio between the second conductive structure and the first metal particles.Further comparison between Embodiment 6 and Embodiment 7 shows that, when the number ratio between the second conductive structure and the first metal particles is out of the range of 1:4000 to 1:1, the cell performance is slightly inferior to that of the preferred embodiment; when the number ratio is below the optimum range, the series resistance increases and the fill factor decreases, resulting in a slight decrease in the photoelectric conversion efficiency. When the number ratio is larger than the optimum range, the open circuit voltage decreases and the photoelectric conversion efficiency decreases due to the stronger corrosion of the metal electrode with respect to the substrate.The technical solutions disclosed in the embodiments of the present invention have been described above in detail. Specific examples are used herein to illustrate the principle and implementations of the present invention. The descriptions of the above embodiments are only for explaining the technical solution of the present invention and its gist. Moreover, modifications of the specific implementations and the scope of application will be apparent to those skilled in the art in accordance with the ideas of the present invention. In summary, the content of this patent application is not to be understood as limiting the present invention.

Claims

A metal-semiconductor contact structure, comprising: a doped semiconductor layer (200); a metal electrode (300) in contact with the doped semiconductor layer; and a first conductive region (1a) provided at a contact interface between the doped semiconductor layer and the metal electrode, the first conductive region comprising: a first conductive structure (11), the first conductive structure comprising a plurality of first metal particles (111) distributed in the first conductive region, the first metal particles having a spherical shape and / or an ellipsoidal shape, at least a part of the first conductive structure being in contact with the doped semiconductor layer; a second conductive structure (12), wherein the second conductive structure is radial, at least a part of the second conductive structure is disposed on a surface of the first metal particles, and a radial direction of the second conductive structure is a direction toward the metal electrode, wherein the metal electrode, the first metal particles, and the second conductive structure all have the same metal element.The metal-semiconductor contact structure according to claim 1, wherein the number ratio between the second conductive structure and the first metal particles is 1:4000 to 1:1.The metal-semiconductor contact structure according to claim 2, wherein the number ratio between the second conductive structure and the first metal particles is 1:1000 to 1:20.The metal-semiconductor contact structure according to claim 1, wherein the particle size of the first metal particles is 20 nm to 360 nm.The metal-semiconductor contact structure according to claim 1, wherein in each 10 μm × 10 μm region of the first conductive region, the number of the first metal particles is 200 to 4000, the number of a part of the first metal particles having a particle size in the range of 100 nm to 360 nm is 100 to 1500, and the number of another part of the first metal particles having a particle size in the range of less than 100 nm is 100 to 2500.The metal-semiconductor contact structure according to claim 1, wherein the first conductive structure further comprises second metal particles (112) attached to a surface of the first metal particles, the first metal particles having a particle size of 20 nm to 360 nm, the second metal particles having a particle size of less than 20 nm, the number of the second metal particles on one of the first metal particles is 1 to 50, and the second metal particles have the same metal element as the first metal particles.The metal-semiconductor contact structure of claim 1, wherein a size of the second conductive structure is 0.2 μm to 2 μm.The metal-semiconductor contact structure according to claim 1, wherein a plurality of second conductive structures are present in each 10 μm×10 μm region of the first conductive region, the number of the second conductive structures being 2 to 450, the number of a part of the second conductive structures having a particle size in the range of 1 μm to 2 μm being 1 to 100, and the number of another part of the second conductive structures having a particle size in the range of less than 1 μm being 1 to 350.The metal-semiconductor contact structure according to claim 1, wherein the second conductive structure comprises a plurality of stripe-shaped first sub-structures (121) diverging toward the metal electrode, and wherein the number of the first sub-structures is 2 to 20.The metal-semiconductor contact structure according to claim 9, wherein each of the first sub-structures is composed of a plurality of second sub-structures, each of the second sub-structures has the shape of a wheat grain, and the plurality of second sub-structures (1211) are combined with each other to form the first sub-structure in the shape of wheat ears, the second sub-structures having a cross-sectional dimension of 2 nm to 40 nm.The metal-semiconductor contact structure according to any one of claims 1 to 10, wherein a second conductive region (1b) is further provided at a contact interface between the doped semiconductor layer and the metal electrode, wherein the second conductive region is arranged at an edge of the first conductive region and the second conductive region comprises an unfired passivation layer, wherein the first conductive structure and / or the second conductive structure is provided between the unfired passivation layer (400) and the metal electrode, when the second conductive region comprises the first conductive structure, a density of the first conductive structure in the second conductive region is less than a density of the first conductive structure in the first conductive region, and when the second conductive region comprises the second conductive structure, a density of the second conductive structure in the second conductive region is less than a density of the second conductive structure in the first conductive region.The metal-semiconductor contact structure according to any one of claims 1 to 10, wherein the doped semiconductor layer comprises a doped amorphous silicon layer, a doped polycrystalline silicon layer, a doped microcrystalline silicon layer or a doped crystalline silicon layer, and / or a doping element in the doped semiconductor layer is an N-type element or a P-type element, and / or the metal element comprises a silver element, and / or at least a part of the second conductive structure is arranged on a surface facing the metal electrode of the doped semiconductor layer.A solar cell, the solar cell comprising: a silicon substrate (100); a doped semiconductor layer (200), the doped semiconductor layer being provided on the silicon substrate; a metal electrode (300) in contact with the doped semiconductor layer; and a first conductive region (1a) provided at a contact interface between the doped semiconductor layer and the metal electrode, the first conductive region comprising: a first conductive structure (11), the first conductive structure comprising a plurality of first metal particles (111) distributed in the first conductive region, the first metal particles having a spherical shape and / or an ellipsoidal shape, at least a part of the first conductive structure being in contact with the doped semiconductor layer; a second conductive structure (12), wherein the second conductive structure is radial, at least a part of the second conductive structure is disposed on a surface of the first metal particles, and a radial direction of the second conductive structure is a direction toward the metal electrode, wherein the metal electrode, the first metal particles, and the second conductive structure all have the same metal element.The solar cell according to claim 13, wherein the number ratio between the second conductive structure and the first metal particles is 1:4000 to 1:1.The solar cell of claim 13, wherein the number ratio between the second conductive structure and the first metal particles is 1:1000 to 1:20, and / or a particle size of the first metal particles is 20 nm to 360 nm; and / or in any 10 μm×10 μm range of the first conductive region, the number of the first metal particles is 200 to 4000, wherein the number of a part of the first metal particles having a particle size in the range of 100 nm to 360 nm is 100 to 1500, and the number of another part of the first metal particles having a particle size in the range of less than 100 nm is 100 to 2500, and / or the first conductive structure further comprises second metal particles attached to a surface of the first metal particles, wherein the first metal particles have a particle size of 20 nm to 360 nm, the second metal particles have a particle size of less than 20 nm, the number of second metal particles on one of the first metal particles is 1 to 50, and the second metal particles have the same metal element as the first metal particles, and / or a size of the second conductive structure is 0.2 μm to 2 μm, and / or a plurality of second conductive structures are present in each 10 μm×10 μm region of the first conductive region, the number of the second conductive structures is 2 to 450, wherein the number of a part of the second conductive structures having a particle size in a range of 1 μm to 2 μm is 1 to 100, and the number of another part of the second conductive structures having a particle size in a range of less than 1 μm is 1 to 350, and / or the second conductive structure has a plurality of strip-shaped first sub-structures diverging toward the metal electrode, and wherein the number of the first sub-structures is 2 to 20, and / or each of the first sub-structures consists of a plurality of second sub-structures, each of the second sub-structures has the shape of a wheat grain, and a plurality of the second sub-structures are combined with each other to form the first sub-structure in the shape of wheat ears, the second sub-structure having a cross-sectional dimension of 2 nm to 40 nm, and / or a second conductive region is further provided at a contact interface between the doped semiconductor layer and the metal electrode, the second conductive region being arranged at an edge of the first conductive region and the second conductive region having an unfired passivation layer, the first conductive structure and / or the second conductive structure being provided between the unfired passivation layer and the metal electrode, wherein, when the second conductive region includes the first conductive structure, a density of the first conductive structure in the second conductive region is less than a density of the first conductive structure in the first conductive region, and when the second conductive region includes the second conductive structure, a density of the second conductive structure in the second conductive region is less than a density of the second conductive structure in the first conductive region.The solar cell of claim 13, wherein the solar cell further comprises: a dielectric layer (500) provided between the silicon substrate and the doped semiconductor layer; and / or the solar cell further comprises a passivation layer (400) provided on a side of the doped semiconductor layer facing away from the silicon substrate.The solar cell of claim 13, wherein the doped semiconductor layer includes an N-doped semiconductor layer (201) and a P-doped semiconductor layer (202), the N-doped semiconductor layer and the P-doped semiconductor layer are arranged in an interdigital arrangement on a back surface of the silicon substrate, and an isolation region is provided between the N-doped semiconductor layer and the P-doped semiconductor layer, and the metal electrode includes a first metal electrode (301) and a second metal electrode (302), wherein the first metal electrode and the N-doped semiconductor layer are in contact with each other, and the second metal electrode and the P-doped semiconductor layer are in contact with each other.A photovoltaic module, wherein the photovoltaic module comprises the solar cell according to any one of claims 13 to 17, wherein a plurality of the solar cells are connected in series and / or in parallel to obtain a solar cell string; and a packaging structure, wherein the solar cell string is packaged in the packaging structure.

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