Contact resistance test method

Abstract

This application relates to the field of solar cell technology, and more particularly to a method for testing contact resistance. The embodiments of this application are used to test the contact resistance generated at the interface between a target metal oxide layer and a TCO layer. This method involves designing a differential comparison between a first device (containing the target metal oxide layer / target TCO interface) and a second device (not containing the target metal oxide layer / target TCO interface), and using a formula to isolate the contributions of the device's resistance (R1, R2) and the material's bulk resistance (i.e., the product of line resistance and thickness), thereby extracting the interface contact resistance value determined by the interface characteristics. This allows for accurate testing of the contact resistance of the target metal oxide layer / target TCO interface.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to a method for testing contact resistance. Background Technology

[0002] With the continuous advancement of photovoltaic technology, the energy conversion efficiency of single-junction silicon cells is gradually approaching its theoretical limit. To further improve the efficiency of photovoltaic cells and overcome the thermal relaxation losses present in single-junction cells, multi-junction cell technology has emerged. Currently, by stacking wide-bandgap perovskite cells on crystalline silicon cells, a conversion efficiency as high as 35% can be achieved, significantly exceeding the 27.8% level of existing single-junction silicon cells, fully demonstrating the significant performance advantages of multi-junction structures.

[0003] In tandem solar cells, perovskite solar cells typically consist of an electron transport layer, a perovskite active layer, a hole transport layer, and electrodes. The electron transport layer uses C0... 60 Composite structure with SnO2: C 60 The primary function of SnO2 is to extract charge carriers and mitigate energy level abrupt changes at the perovskite-SnO2 interface, thereby lowering the charge transport barrier. SnO2, on the other hand, acts to prevent potential damage to the perovskite layer from subsequent magnetron sputtering processes, while simultaneously promoting efficient electron-hole pair separation and enhancing electron transport capabilities. Despite these advantages of SnO2 in the electron transport layer, current methods for measuring the interfacial contact resistance between SnO2 and transparent conductive oxide (TCO) are lacking. The inability to measure this interfacial contact resistance limits in-depth research into the interfacial loss mechanisms in this type of battery.

[0004] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the Invention

[0005] This application provides a method for testing contact resistance to solve or alleviate one or more of the technical problems mentioned above.

[0006] This application provides a method for testing contact resistance, including the following steps:

[0007] Provide a first device and a second device;

[0008] The first device includes a first symmetrical double-sided carrier selective contact structure. The first symmetrical double-sided carrier selective contact structure has a front side and a back side disposed opposite to each other. The front side of the first symmetrical double-sided carrier selective contact structure is provided with a first transparent conductive oxide (TCO) layer, a first metal oxide layer, a second TCO layer and a first electrode stacked in sequence. The back side of the first symmetrical double-sided carrier selective contact structure is provided with a third TCO layer, a second metal oxide layer, a fourth TCO layer and a second electrode stacked in sequence.

[0009] The second device includes a second symmetrical double-sided carrier selective contact structure, a fifth TCO layer directly disposed on the front side of the second symmetrical double-sided carrier selective contact structure, a sixth TCO layer directly disposed on the back side of the second symmetrical double-sided carrier selective contact structure, a third electrode disposed on the fifth TCO layer, and a fourth electrode disposed on the sixth TCO layer.

[0010] The second TCO layer and the fifth TCO layer have the same material and dimensions;

[0011] The fourth TCO layer and the sixth TCO layer have the same material and size;

[0012] The first TCO layer and the third TCO layer have the same material and size;

[0013] The first metal oxide layer and the second metal oxide layer have the same material and size;

[0014] Based on the contact interface to be tested, obtain the target metal oxide layer and the target TCO layer;

[0015] Construct the first device and the second device such that the first metal oxide layer and the target metal oxide layer have the same material and size, and the first TCO layer and the target TCO layer have the same material and size, and obtain the resistance R1 of the first device and the resistance R2 of the second device respectively.

[0016] Obtain the thickness T of the target metal oxide layer 金属氧化物层、 The line resistance R of the target metal oxide layer wire-金属氧化物层、 The thickness T of the target TCO layer TCO层 The line resistance R of the target TCO layer wire-TCO层 And the contact area S between the target metal oxide layer and the target TCO layer;

[0017] The contact resistance R between the target metal oxide layer and the target TCO layer is obtained according to formula (1). contact :

[0018] R contact =(R1-R2-T 金属氧化物层 ×R wire-金属氧化物层 ×2-T TCO层 ×R wire-TCO层 ×2) / 4×S(1).

[0019] This application embodiment is used to test the contact resistance generated at the interface between the target metal oxide layer and the TCO layer. The method is to design a differential comparison between a first device (containing the target metal oxide layer / target TCO interface) and a second device (not containing the target metal oxide layer / target TCO interface), and use a formula to remove the contribution of the device resistance (R1, R2) and the bulk resistance of the material itself (i.e., the product of line resistance and thickness), thereby extracting the interface contact resistance value determined by the interface characteristics, which can accurately test the contact resistance of the target metal oxide layer / target TCO interface. Attached Figure Description

[0020] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0021] Figure 1 This is a schematic diagram of the structure of the first device provided in the embodiments of this application;

[0022] Figure 2 This is a schematic diagram of the structure of the second device provided in the embodiments of this application;

[0023] Figure 3 This application describes the effect of the thickness of the first metal oxide layer on the electrical performance of the device, as provided in the embodiments of this application. Figure 3 Figure (a) shows the current versus voltage trend of devices under first metal oxide layers of different thicknesses. Figure 3 (b) is a graph showing the trend of resistance as a function of the thickness of the first metal oxide layer;

[0024] Figure 4 This application describes the effect of the thickness of the second TCO layer provided in the embodiments on the electrical performance of the device. Figure 4 Figure (a) shows the current versus voltage trend of devices under second TCO layers of different thicknesses. Figure 4 (b) is a graph showing the trend of resistance as a function of the thickness of the second TCO layer;

[0025] Figure 5 It is a current-voltage diagram of the device under test and the reference device;

[0026] Figure 6This is the IV curve of the first device in the embodiment;

[0027] Figure 7 This is the IV curve of the second device in the embodiment;

[0028] Figure 8 These are the IV curves of the first device with SnO2 layers of different thicknesses in the embodiment;

[0029] Figure 9 This is a graph showing the trend of resistance versus SnO2 layer thickness in the first device of the embodiment;

[0030] Figure 10 These are the IV curves of the first device with IZO layers of different thicknesses in the embodiment;

[0031] Figure 11 This is a graph showing the trend of resistance versus IZO layer thickness for the second device in the embodiment.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1-Silicon substrate; 2-First intrinsic amorphous silicon layer; 3-First doped layer; 4-Second intrinsic amorphous silicon layer; 5-Second doped layer; 6-First TCO layer; 7-First metal oxide layer; 8-Second TCO layer; 9-Third TCO layer; 10-Second metal oxide layer; 11-Fourth TCO layer; 12-First electrode; 13-Second electrode; 14-Fifth TCO layer; 15-Sixth TCO layer; 16-Third electrode; 17-Fourth electrode. Detailed Implementation

[0034] The embodiments of this application are described in detail below, with examples of the embodiments illustrated in the accompanying drawings. In the drawings, for clarity, the dimensions of layers, regions, and elements, as well as their relative dimensions, may be exaggerated. Throughout, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0035] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And the discussion of a second element, component, area, layer, or portion does not imply that the first element, component, area, layer, or portion necessarily exists in this application.

[0036] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0037] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0038] In this application, when numerical intervals (i.e., numerical ranges) are involved, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, etc.

[0039] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. It should be understood that these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein.

[0040] This application provides a method for testing contact resistance. The method for testing contact resistance may include the following steps:

[0041] S1. Provide the first device and the second device;

[0042] In some embodiments, see Figure 1 The first device includes a first symmetrical double-sided carrier selective contact structure. The first symmetrical double-sided carrier selective contact structure has a front side and a back side arranged opposite to each other. The front side of the first symmetrical double-sided carrier selective contact structure is provided with a first TCO layer 6, a first metal oxide layer 7, a second TCO layer 8 and a first electrode 12 stacked in sequence. The back side of the first symmetrical double-sided carrier selective contact structure is provided with a third TCO layer 9, a second metal oxide layer 10, a fourth TCO layer 11 and a second electrode 13 stacked in sequence. Therefore, due to the presence of the first symmetrical double-sided carrier selective contact structure, the two sides of the first symmetrical double-sided carrier selective contact structure are symmetrically arranged, and it has bidirectional linear conduction electrical characteristics.

[0043] In some embodiments, see Figure 2The second device includes a second symmetrical double-sided carrier selective contact structure, a fifth TCO layer 14 directly disposed on its front side, a sixth TCO layer 15 directly disposed on its back side, a third electrode 16 disposed on the fifth TCO layer 14, and a fourth electrode 17 disposed on the sixth TCO layer 15. Simultaneously, the first and second devices satisfy the following conditions: the second symmetrical double-sided carrier selective contact structure and the first symmetrical double-sided carrier selective contact structure have the same material and size; the second TCO layer 8 and the fifth TCO layer 14 have the same material and size; the fourth TCO layer 11 and the sixth TCO layer 15 have the same material and size. Therefore, compared to the first device, the second device does not have the first TCO layer 6 and the first metal oxide layer 7 disposed on its front side, and it does not have the third TCO layer 9 and the second metal oxide layer 10 disposed on its back side. The resistance of the first device, compared to the resistance of the second device, is increased by the bulk resistance of the metal oxide layer, the bulk resistance of the TCO (first TCO layer 6 and third TCO layer 9), and the contact resistance generated by the contact between the metal oxide layer and the TCO.

[0044] It should be noted that in the embodiments of this application, "same size" means that the size is the same in all directions.

[0045] In some embodiments, see Figure 1 The first symmetrical bifacial carrier-selective contact structure includes a silicon substrate 1. A first intrinsic amorphous silicon layer 2 and a first doped layer 3 are sequentially stacked on the front side of the silicon substrate 1, and a second intrinsic amorphous silicon layer 4 and a second doped layer 5 are sequentially stacked on the back side of the silicon substrate. It should be noted that the first doped layer 3 and the second doped layer 5 are of the same type, that is, both the first doped layer 3 and the second doped layer 5 are either p-type doped or both n-type doped. When the silicon substrate 1 is n-type, both the first doped layer 3 and the second doped layer 5 are n-type doped.

[0046] Optionally, the first doped layer 3 can be doped amorphous silicon or doped microcrystalline silicon.

[0047] Optionally, the second doped layer 5 can be doped amorphous silicon or doped microcrystalline silicon.

[0048] Optionally, the first TCO layer, the second TCO layer, the third TCO layer, and the fourth TCO layer can all be fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), indium tin oxide (ITO), indium-doped zinc oxide (IZO), etc.

[0049] In some embodiments, the first metal oxide layer and the second metal oxide layer have the same material and size; the first TCO layer and the third TCO layer have the same material and size; thus, the same contact interface can be formed on both sides of the first device, which can reduce variable factors and facilitate the determination of the contact resistance of the target TCO layer and the target metal oxide layer.

[0050] Optionally, the first metal oxide layer and the second metal oxide layer are simultaneously at least one of ZnO, SnO2, TiO2, In2O3, CeO2, WO3, and MoO3. For example, they can both be SnO2, in which case the contact interface is a TCO / SnO2 interface.

[0051] S2. Based on the contact interface to be tested, obtain the target metal oxide layer and the target TCO layer;

[0052] A first device and a second device are constructed such that the first metal oxide layer 7 and the target metal oxide layer have the same material and size, and the first TCO layer 6 and the target TCO layer have the same material and size. The resistance R1 of the first device and the resistance R2 of the second device are obtained respectively. In this case, the first TCO layer 6 and the first metal oxide layer 7 in the first device are used to simulate the contact interface to be tested. For example, see Figure 5 The corresponding resistance can be obtained through the VI curve.

[0053] S3. Obtain the thickness T of the target metal oxide layer. 金属氧化物层 Line resistance R of the target metal oxide layer wire-金属氧化物层 Thickness T of the target TCO layer TCO层 Line resistance R of the target TCO layer wire-TCO层 And the contact area S between the two;

[0054] The contact resistance Rcontact of the target metal oxide layer and the target TCO layer is obtained according to equation (1);

[0055] R contact =(R1-R2-T) 金属氧化物层 ×R wire-金属氧化物层 ×2-T TCO层 ×R wire-TCO层 ×2) / 4×S(1).

[0056] Therefore, by subtracting the resistances of the first and second devices, and also subtracting the resistances of the two metal oxide layers and the two TCO layers, the remaining value is the resistance value generated by the contact of the four interfaces. Dividing this value by 4 and then multiplying it by the contact area gives the contact resistance.

[0057] This application embodiment is used to test the contact resistance generated at the interface between the target metal oxide layer and the TCO layer. The method is to design a differential comparison between a first device (containing the target metal oxide layer / target TCO interface) and a second device (not containing the target metal oxide layer / target TCO interface), and use a formula to remove the contribution of the device resistance (R1, R2) and the bulk resistance of the material itself (i.e., the product of line resistance and thickness), thereby extracting the interface contact resistance value determined by the interface characteristics, which can accurately test the contact resistance of the target metal oxide layer / target TCO interface.

[0058] It should be noted that the contact resistance in this application refers to an additional, localized resistance generated by the characteristics of the interface itself when current flows through the contact interface of two different physical phases (such as metal and semiconductor, two different thin film materials, etc.).

[0059] In some embodiments, the line resistance R of the target metal oxide layer wire-金属氧化物层 The methods for obtaining it may include:

[0060] S301. Construct several first devices, each with a different thickness of the first metal oxide layer, while the rest are the same; that is, change the thickness of the first metal oxide layer (and the second metal oxide layer) in the first device to obtain a series of first devices with different thicknesses of the first metal oxide layer (and the second metal oxide layer); and the first metal oxide layer has the same material as the target metal oxide layer.

[0061] Optionally, the thickness of the first metal oxide layer can be 1 nm to 500 nm. This allows the metal oxide layer to be closer to the contact interface, resulting in more accurate electrical properties. For example, the thickness of the first metal oxide layer can be 1 nm, 10 nm, 30 nm, 50 nm, 150 nm, 250 nm, 350 nm, 500 nm, etc.

[0062] S302. Obtain the resistance of the first device respectively, and establish a functional relationship between the resistance and the thickness of the first metal oxide layer.

[0063] Optionally, the number of the first device can be six or more. This allows for the acquisition of six or more sets of data (resistance, thickness of the first metal oxide layer), enabling a more accurate establishment of the corresponding functional relationship.

[0064] Optionally, obtaining the resistance of the first device includes the following steps: testing the current of the first device under a voltage of -10V to 10V, and obtaining the resistance based on the voltage and current.

[0065] This application does not impose any limitations on the method for establishing a corresponding functional relationship based on a limited set of data points (resistance, thickness of the first metal oxide layer). Any data fitting algorithm known in the art can be used, including but not limited to least squares, nonlinear regression, or machine learning algorithms. For example, the least squares method can be used to fit a linear relationship to the discrete data set of resistance and the thickness of the first metal oxide layer. Preferably, the established functional relationship is linear. This facilitates the determination of the line resistance of the first metal oxide layer.

[0066] For example, to obtain the resistance of each first device, see... Figure 3 As shown in (a). The functional relationship between resistance and the thickness of the first metal oxide layer is established as shown in [reference]. Figure 3 As shown in (b).

[0067] S303. Obtain the slope of the functional relationship, which is the line resistance R of the target metal oxide layer. wire-金属氧化物层 .

[0068] In some embodiments, the line resistance R of the target TCO layer wire-TCO层 The methods for obtaining it include:

[0069] S310. Construct several first devices, each with a different thickness of the first TCO layer, while the remaining thicknesses are the same; that is, by changing the thickness of the first TCO layer (including the third TCO layer) in the first device, a series of first devices with different first TCO layer thicknesses are obtained. Furthermore, the first TCO layer has the same material as the target TCO layer.

[0070] Optionally, the thickness of the first TCO layer can be 1 nm to 1000 nm. This allows the TCO layer to be closer to the contact interface, resulting in more accurate electrical properties. For example, the thickness of the first TCO layer can be 1 nm, 100 nm, 200 nm, 500 nm, 800 nm, 1000 nm, etc.

[0071] S320. Obtain the resistance of the first device respectively, and establish a functional relationship between the resistance and the thickness of the first TCO layer;

[0072] Optionally, the number of the first device can be six or more. This allows for the acquisition of more than six sets of data (resistance, thickness of the first TCO layer), enabling a more accurate establishment of the corresponding functional relationship.

[0073] Optionally, obtaining the resistance of the first device includes the following steps: testing the current of the first device under a voltage of -10V to 10V, and obtaining the resistance based on the voltage and current.

[0074] This application does not impose any limitations on the method for establishing a corresponding functional relationship based on a limited number of data points (resistance, thickness of the first metal oxide layer). Any data fitting algorithm known in the art can be used, including but not limited to least squares, nonlinear regression, or machine learning algorithms.

[0075] Preferably, the established functional relationship is linear. This makes it easier to obtain the line resistance of the first TCO layer.

[0076] For example, to obtain the resistance of each first device, see... Figure 4 As shown in (a). The functional relationship between resistance and the thickness of the first TCO layer is established in [reference needed]. Figure 4 As shown in (b).

[0077] The contact resistance testing method of this application can be used to test the interface contact resistance of solar cells. For example, the interface of a solar cell can be the contact interface between a metal oxide layer and a TCO layer.

[0078] The following describes a method for testing contact resistance based on embodiments of this application.

[0079]

Example

[0080] A method for testing the interfacial contact resistance of SnO2 and IZO

[0081] This embodiment provides a specific contact resistance testing method for accurately measuring the interfacial contact resistance between the SnO2 electron transport layer and the IZO (indium-doped zinc oxide) transparent conductive layer in a tandem solar cell.

[0082] A method for testing contact resistance includes the following steps:

[0083] Step 1: Device fabrication and structure

[0084] Fabrication of the first device (device under test):

[0085] A silicon substrate is provided, on the front side of which an i-type amorphous silicon layer and an n-type doped amorphous silicon layer are sequentially deposited, and on the back side of which an i-type amorphous silicon layer and an n-type doped amorphous silicon layer are sequentially deposited. On the n-type doped amorphous silicon layer on the front side, the following functional layers are sequentially deposited: a first IZO layer (i.e., a first TCO layer) with a thickness of 80 nm; a first SnO2 layer with a thickness of 30 nm; a second IZO layer (i.e., a second TCO layer) with a thickness of 80 nm; and a first silver electrode (first electrode). On the n-type doped amorphous silicon layer on the back side, the following functional layers are sequentially deposited: a third IZO layer (i.e., a third TCO layer) with a thickness of 80 nm; a second SnO2 layer with a thickness of 30 nm; a fourth IZO layer (i.e., a fourth TCO layer) with a thickness of 80 nm; and a second silver electrode (second electrode).

[0086] All IZO layers (first, second, third, and fourth) are identical in material and area. The two SnO2 layers (first and second) are also identical in material and area.

[0087] Fabrication of the second device (reference device):

[0088] The same silicon substrate as the first device is provided. An i-type amorphous silicon layer and an n-type doped amorphous silicon layer are deposited sequentially on the front side of the silicon substrate, and an i-type amorphous silicon layer and an n-type doped amorphous silicon layer are deposited sequentially on the back side of the silicon substrate. A fifth IZO layer (80 nm thick) and a third silver electrode are deposited on the front side. A sixth IZO layer (80 nm thick) and a fourth silver electrode are deposited on the back side.

[0089] The second device does not contain any SnO2 layer or the adjacent first IZO layer and third IZO layer.

[0090] 2. Obtaining key parameters

[0091] (1) Measuring resistance

[0092] Using a semiconductor parameter analyzer, the current-voltage (IV) characteristic curves of the first and second devices were measured at a scan voltage ranging from -10 V to +10 V. The IV curve of the first device is shown in [Figure number missing]. Figure 6 The IV curve of the second device is shown in [reference needed]. Figure 7 As can be seen, both IV curves show a good linear relationship, indicating that the device has ohmic characteristics.

[0093] The resistance of the first device was calculated to be R1 = 0.07604068 Ω and the resistance of the second device was calculated to be R2 = 0.0760106 Ω by linear fitting.

[0094] (2) Obtain the line resistance (R) of the SnO2 layer _wire-SnO2 )

[0095] Six first devices were fabricated, with structures identical to the first devices described above. The only difference was the thickness of the first SnO2 layer (and the second SnO2 layer), which were 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, and 60 nm, respectively.

[0096] Perform IV testing on each device under the same conditions (-10V to +10V), see [link to documentation]. Figure 8 .

[0097] based on Figure 8 The IV curves were obtained, and the resistances at each level were plotted with the SnO2 layer thickness on the x-axis and the resistance on the y-axis. For example... Figure 9As shown, the data points exhibit a good linear distribution.

[0098] Linear regression fitting is performed using the least squares method to obtain the reciprocal k of the slope of the fitted line. _SnO2 = 10 -6 Ω / nm. According to the definition of resistance (R = ρ×L / A, where thickness T corresponds to length L), this slope is physically the line resistance R of SnO2 material. _wire-SnO2 = 10 -6 Ω / nm.

[0099] (3) Obtain the line resistance (R) of the IZO layer _wire-TCO )

[0100] Six first devices were fabricated in the same manner, with the same structure as the first devices described above. The only difference was the thickness of the first IZO layer (and the corresponding other IZO layers), which were 40 nm, 60 nm, 80 nm, 100 nm, 120 nm, and 140 nm, respectively.

[0101] IV testing was performed under the same conditions, and the results are shown below. Figure 10 Plot a graph with IZO layer thickness on the x-axis and resistance on the y-axis, as shown below. Figure 11 As shown.

[0102] Linear regression fitting is performed using the least squares method to obtain the reciprocal k of the slope of the fitted line. _IZO =10 -9 Ω / nm. This slope is the line resistance R of the IZO material. _wire-TCO = 10 -9 Ω / nm.

[0103] (4) Other parameters

[0104] Target SnO2 layer thickness T _SnO2 In this embodiment, the designed thickness of the SnO2 layer at the interface to be tested is 30 nm.

[0105] Target TCO layer thickness T _TCO In this embodiment, the designed thickness of the IZO layer at the interface to be tested is 80 nm.

[0106] Contact area S: The effective contact area between SnO2 and IZO is 1 cm². 2 .

[0107] 3. Calculation of contact resistance

[0108] Substituting all the parameters obtained above into equation (1) for calculation, the contact resistance is found to be 5 mΩ·cm. 2 .

[0109] Results Analysis: The calculated contact resistance value is 5 mΩ·cm 2 The results show that the SnO2 / IZO interface contact resistance measured by this method is a very small value (close to zero), which proves that the interface has excellent ohmic contact characteristics and the charge carrier transport barrier at this interface is extremely low, which is crucial for the fabrication of high-performance tandem solar cells.

[0110] It should be noted that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. The directional terms "inner" and "outer" refer to the inside or outside relative to the outline of the component itself. For example, if a device in the drawings is inverted, a device described as "above" or "on top of" other devices or structures will subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0111] It should also be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this application refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0112] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0113] It should also be noted that the above are merely preferred embodiments of this application and do not limit the scope of patent protection of this application. Any equivalent structural or procedural changes made using the content of this application’s specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A method of testing contact resistance, characterized by, The method comprises the following steps: providing a first device and a second device; wherein the first device comprises a first symmetrical double-sided carrier-selective contact structure, the first symmetrical double-sided carrier-selective contact structure has oppositely arranged front and back surfaces, the front surface of the first symmetrical double-sided carrier-selective contact structure is provided with a first transparent conductive oxide layer, a first metal oxide layer, a second transparent conductive oxide layer and a first electrode which are sequentially stacked, and the back surface of the first symmetrical double-sided carrier-selective contact structure is provided with a third transparent conductive oxide layer, a second metal oxide layer, a fourth transparent conductive oxide layer and a second electrode which are sequentially stacked; the second device comprises a second symmetrical double-sided carrier-selective contact structure, a fifth transparent conductive oxide layer directly arranged on the front surface of the second symmetrical double-sided carrier-selective contact structure, a sixth transparent conductive oxide layer directly arranged on the back surface of the second symmetrical double-sided carrier-selective contact structure, a third electrode arranged on the fifth transparent conductive oxide layer, and a fourth electrode arranged on the sixth transparent conductive oxide layer; the second symmetrical double-sided carrier-selective contact structure and the first symmetrical double-sided carrier-selective contact structure have the same material and size; the second transparent conductive oxide layer and the fifth transparent conductive oxide layer have the same material and size; the fourth transparent conductive oxide layer and the sixth transparent conductive oxide layer have the same material and size; the first transparent conductive oxide layer and the third transparent conductive oxide layer have the same material and size; the first metal oxide layer and the second metal oxide layer have the same material and size; according to the contact interface to be detected, a target metal oxide layer and a target transparent conductive oxide layer are obtained; the first device and the second device are constructed so that the first metal oxide layer has the same material and size as the target metal oxide layer, and the first transparent conductive oxide layer has the same material and size as the target transparent conductive oxide layer, and the resistance R1 of the first device and the resistance R2 of the second device are obtained respectively; acquiring a thickness T of the target metal oxide layer 金属氧化物层、 a line resistance R of the target metal oxide layer wire-金属氧化物层、 a thickness T of the target transparent conductive oxide layer 透明导电氧化物层 a line resistance R of the target transparent conductive oxide layer wire-透明导电氧化物层 and a contact area S between the target metal oxide layer and the target transparent conductive oxide layer The contact resistance R between the target metal oxide layer and the target transparent conductive oxide layer is obtained according to formula (1) contact : R contact = (R1-R2-T 金属氧化物层 ×R wire-金属氧化物层 ×2-T 透明导电氧化物层 ×R wire-透明导电氧化物层 ×2) / 4 x S(1); The line resistance R of the target metal oxide layer wire-金属氧化物层 The acquisition method comprises: a plurality of the first devices are constructed so that the thicknesses of the first metal oxide layers in the respective first devices are different from each other and the remaining parts are the same, and the first metal oxide layer has the same material as the target metal oxide layer; the resistances of the first devices are obtained respectively, and a functional relationship between the resistances and the thicknesses of the first metal oxide layers is established; Obtaining the slope of the function relationship is the linear resistance R of the target metal oxide layer wire-金属氧化物层 ; The line resistance R of the target transparent conductive oxide layer wire-透明导电氧化物层 The acquisition method comprises: a plurality of the first devices are constructed so that the thicknesses of the first transparent conductive oxide layers in the respective first devices are different from each other and the remaining parts are the same, and the first transparent conductive oxide layer has the same material as the target transparent conductive oxide layer; the resistances of the first devices are obtained respectively, and a functional relationship between the resistances and the thicknesses of the first transparent conductive oxide layers is established; The slope of the function relationship is obtained, that is, the line resistance R of the target transparent conductive oxide layer wire-透明导电氧化物层 .

2. The method of testing contact resistance according to claim 1, wherein the thickness of the first metal oxide layer is 1 nm to 500 nm; and / or the functional relationship is a linear relationship.

3. The method of testing contact resistance according to claim 1, wherein The number of the first devices is more than 6.

4. The method of testing contact resistance according to claim 1, wherein The resistance of the first device is obtained by testing the current of the first device under a voltage of -10 V to 10 V, and obtaining the resistance based on the voltage and the current; and / or The function relationship between the resistance and the thickness of the first metal oxide layer is established by fitting the discrete data set of the resistance and the thickness of the first metal oxide layer into a linear relationship using a linear fitting method.

5. The method of testing contact resistance according to claim 1, wherein The thickness of the first transparent conductive oxide layer is 1 nm to 1000 nm; and / or The function relationship is a linear relationship; and / or The material of the first transparent conductive oxide layer includes at least one of fluorine-doped tin oxide, aluminum-doped zinc oxide, indium tin oxide, and indium-doped zinc oxide.

6. The method of testing contact resistance according to claim 1, wherein The resistance of the first device is obtained by testing the current of the first device under a voltage of -10 V to 10 V, and obtaining the resistance based on the voltage and the current; and / or The function relationship between the resistance and the thickness of the first transparent conductive oxide layer is established by fitting the discrete data set of the resistance and the thickness of the first transparent conductive oxide layer into a linear relationship using a linear fitting method.

7. The method of testing contact resistance according to claim 1, wherein The first symmetric double-sided carrier selective contact structure and the second symmetric double-sided carrier selective contact structure each independently include a silicon substrate, the front surface of the silicon substrate is sequentially stacked with a first intrinsic amorphous silicon layer and a first doped layer, and the back surface of the silicon substrate is sequentially stacked with a second intrinsic amorphous silicon layer and a second doped layer. The first doped layer and the second doped layer are of the same type; and the first doped layer and the second doped layer are independently doped amorphous silicon or doped microcrystalline silicon.

8. The method of testing contact resistance according to claim 1, wherein, The first metal oxide layer and the second metal oxide layer are at least one of ZnO, SnO2, TiO2, In2O3, CeO2, WO3, and MoO3.

9. The method of testing contact resistance according to any one of claims 1 to 8, wherein The interface contact resistance of a solar cell is tested, and the interface includes a contact interface of a metal oxide layer and a transparent conductive oxide layer.

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