A transparent conductive passivation contact structure for silicon-based heterojunction solar cells and a method for preparing the same

Abstract

The present invention discloses a transparent conductive passivation contact structure of a silicon-based heterojunction solar cell and a preparation method thereof. The preparation method comprises the following steps: texturing an n-type silicon wafer and then performing standard RCA cleaning; preparing a tunneling passivation layer on one side of the cleaned n-type silicon wafer; the tunneling passivation layer is taken from one or a stack of silicon oxide, aluminum oxide, and titanium oxide; preparing an electron transport layer on the surface of the tunneling passivation layer; the electron transport layer is taken from one or a stack of aluminum-doped zinc oxide, boron-doped zinc oxide, and zinc hydroxide-doped zinc oxide; preparing a sacrificial layer on the surface of the electron transport layer; the sacrificial layer is taken from one or a stack of aluminum oxide and silicon nitride; after annealing, the sacrificial layer is removed by etching to obtain the structure. In the present invention, hydrogen in the hydrogen-containing sacrificial layer diffuses to the interface, compensates for the defects of the passivation layer and the dangling bonds on the silicon surface, and improves the chemical passivation effect of the contact. At the same time, the electron transport layer provides carrier selective transmission and improves the field effect passivation effect.

Description

Technical Field

[0001] The present invention relates to the field of solar cells, and in particular to a transparent conductive passivation contact structure of a silicon-based heterojunction solar cell and a preparation method thereof. Background Art

[0002] The mainstream cell structure in the current silicon-based photovoltaic industry, PERC (Passivated Emitter and Rear SolarCell), replaces the traditional all-aluminum back field by adding a passivation layer on the back of the silicon wafer, thereby reducing the recombination rate on the back side. Since the back passivation layer is an insulating layer, it cannot form an electrode path with the aluminum back field, so it is necessary to use a laser to cut grooves on the back of the silicon wafer to form a local back surface field. Currently, since the metal electrode in the back contact area of ​​this structure is in direct contact with the silicon, the local passivation is poor, and its theoretical efficiency limit is limited to about 24.5%. The industrial conversion efficiency is already close to this limit, which limits the further development of this cell structure.

[0003] The TOPCon cell (Tunnel Oxide Passivated Contact Solar Cell), a technological advancement based on the PERC cell, utilizes a 1-2nm thick tunnel oxide layer on the back of the cell, followed by a doped polysilicon layer to form a passivating contact structure. This provides excellent full-area passivation on the backside of the silicon wafer, improving the cell's conversion efficiency. This structural design bends the energy bands on the silicon wafer's surface, significantly increasing the probability of electron tunneling and reducing contact resistance, thereby increasing the cell's open-circuit voltage and short-circuit current, and thus boosting conversion efficiency. Currently, the HJT cell (Heterojunction with Intrinsic Thin-layer), one of the leading research areas for crystalline silicon solar cells, boasts high conversion efficiency, high bifaciality, virtually no light-induced degradation, and excellent temperature characteristics, thanks to its unique double-sided symmetric structure and the excellent passivation effect of its intrinsic hydrogenated amorphous silicon layer. Its current peak efficiency has reached 26.81%, with a theoretical limit of 29%.

[0004] However, the industrialization of HJT still faces several significant challenges. One major factor limiting its power conversion efficiency is the small bandgap of amorphous silicon in the cell structure. This leads to strong parasitic absorption of short-wavelength sunlight by the front surface (the amorphous silicon layer and the transparent conductive oxide layer), resulting in short-circuit current losses. Furthermore, the transparent conductive oxide layer is typically made of indium tin oxide (ITO), which is expensive, and excessive use can cause environmental problems. Therefore, developing an indium-free transparent conductive oxide material is a current research direction.

[0005] In order to solve the problem of optical parasitic absorption, the use of wide-bandgap undoped materials to replace doped amorphous silicon layers as new electron-selective contact materials is currently a generally recognized research and development direction for silicon-based batteries. The wider optical bandgap of the material can effectively reduce parasitic absorption. The principle of achieving good electrical contact is to make the two carrier transmission capabilities asymmetric through the band-step effect when silicon contacts the transport layer, so as to achieve the purpose of selective carrier transmission. However, the general single-layer undoped electron-selective transport layer material has poor passivation performance and requires the introduction of an additional passivation layer, which makes the process complicated and requires consideration of process compatibility in industry. In addition, the introduction of the passivation layer will also cause additional parasitic light absorption. Combined with the above discussion, it is very important to explore a new transparent conductive passivation contact structure (indium-free). Summary of the Invention

[0006] In order to overcome the problems existing in the prior art, the present invention provides a transparent conductive passivation contact structure of a silicon-based heterojunction solar cell and a preparation method thereof.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A first aspect of the present invention provides a method for preparing a transparent conductive passivation contact structure of a silicon-based heterojunction solar cell, comprising the following steps:

[0009] (1) Texturing the n-type silicon wafer followed by standard RCA cleaning;

[0010] (2) preparing a tunnel passivation layer on one side of the cleaned n-type silicon wafer; the tunnel passivation layer is taken from one or a stack of silicon oxide, aluminum oxide, and titanium oxide; the stack is a stack of two or more materials among silicon oxide, aluminum oxide, and titanium oxide, and the specific structure of the stack is not limited; when the tunnel passivation layer is silicon oxide, the preparation method includes oxygen-containing gas plasma surface treatment, ultraviolet / ozone oxidation method, RCA solution method, thermal oxidation method, thermal nitric acid method, and atomic layer deposition; when the tunnel passivation layer is a material other than silicon oxide, the preparation method includes ion-enhanced chemical vapor deposition (PECVD), atmospheric pressure chemical vapor deposition (APCVD), plasma immersion ion implantation method, magnetron sputtering method, atomic layer deposition method, sol-gel method, and pulsed laser deposition method;

[0011] (3) preparing an electron transport layer on the surface of the tunnel passivation layer; the electron transport layer is taken from one or a stack of aluminum-doped zinc oxide, boron-doped zinc oxide, and zinc hydroxide; the stack is a stack of two or more materials among aluminum-doped zinc oxide, boron-doped zinc oxide, and zinc hydroxide, and the specific structure of the stack is not limited; the preparation method includes atomic layer deposition, magnetron sputtering, thermal evaporation, sol-gel method, and pulsed laser deposition method;

[0012] (4) preparing a sacrificial layer on the surface of the electron transport layer; the sacrificial layer is made of one or a stack of aluminum oxide and silicon nitride; the preparation method includes atomic layer deposition, magnetron sputtering, ion enhanced chemical vapor deposition (PECVD), and atmospheric pressure chemical vapor deposition (APCVD);

[0013] (5) Annealing the structure obtained in step (4), and removing the sacrificial layer by etching after annealing to obtain the transparent conductive passivation contact structure of the silicon-based heterojunction solar cell.

[0014] Preferably, the tunnel passivation layer has a thickness of 0.3 nm to 2.5 nm; further preferably, the tunnel passivation layer has a thickness of 1 nm to 2 nm.

[0015] Preferably, when the tunneling passivation layer is silicon oxide, the preparation method comprises the following steps: placing the cleaned n-type silicon wafer into a chamber of an atomic layer deposition device for plasma oxidation to obtain a tunneling passivation layer.

[0016] Preferably, the thickness of the electron transport layer is 2 nm to 200 nm; further preferably, the thickness of the electron transport layer is 2 nm to 80 nm.

[0017] Preferably, when the electron transport layer is aluminum-doped zinc oxide, the preparation method includes the following steps: introducing a zinc source, an oxygen source, and an aluminum source, and different reactants enter the chamber of the atomic layer deposition equipment, chemically adsorb and react on the surface to form an electron transport layer.

[0018] More preferably, a zinc source and an oxygen source are introduced once to complete a zinc oxide cycle, and the total number of zinc oxide cycles is 10 to 250; an aluminum oxide cycle is inserted after every 2 to 50 zinc oxide cycles. Taking the preparation of zinc oxide as an example, a small reaction cycle of a complete zinc oxide thin film atomic layer deposition method includes: (1) a pulse precursor diethyl zinc source enters the reaction chamber, and a chemical adsorption reaction occurs on the exposed substrate surface; (2) the remaining precursor is purged with an inert gas; (3) a pulse precursor oxygen source (ultrapure water) enters the reaction chamber and chemically adsorbs on the surface; (4) the remaining unreacted precursor and by-products are purged with an inert gas. The above four steps constitute a small reaction cycle of a complete zinc oxide thin film atomic layer deposition method. At this time, an atomic layer deposition zinc oxide film is deposited. Repeat several small reaction cycles to continuously deposit a zinc oxide film of a certain thickness. After repeating the zinc oxide small reaction cycle n times, a small reaction cycle of aluminum oxide atomic layer deposition with trimethylaluminum as aluminum precursor and ultrapure water as oxygen source is inserted, and the above process is collectively referred to as a large cycle, (the pulse time of zinc source, oxygen source and aluminum source is generally 30ms~300ms, and the purge time is generally 1~60s), and a zinc oxide doped aluminum film with a fixed doping ratio is obtained by continuous deposition of the large cycle. Adjusting the above n value can achieve precise control of the doping ratio. Similarly, changing the inserted aluminum oxide deposition small cycle to a doping step with boron trichloride as a boron precursor can achieve effective and controllable boron doping of zinc oxide. Furthermore, adjusting this step to a plasma treatment of a hydrogen-containing gas can achieve effective and controllable hydrogen doping of zinc oxide. Such a technology is called super-cycle atomic layer deposition technology.

[0019] The atomic layer deposition super cycle achieves precise control of the doping level by adjusting the above-mentioned n value. Taking aluminum-doped zinc oxide as an example, when the aluminum doping level is low, that is, the n value is large, the band matching is poor, and the material body resistance is large, which makes the contact resistance large. At the same time, due to the low aluminum doping level, the field effect passivation is poor, resulting in a low open circuit voltage. Therefore, appropriately increasing the aluminum doping level is beneficial to band matching and improving the field effect passivation level, and can effectively reduce the contact resistance. However, as the aluminum doping amount increases, the carrier concentration increases, which increases parasitic absorption and is not conducive to improving efficiency. If n is too low in the atomic layer deposition super cycle process, we hope to further increase the aluminum doping level in zinc oxide. Since the aluminum oxide atomic layer is introduced in the preparation principle cycle, its insulation will lead to an increase in contact resistance, and the aluminum atoms that are not effectively doped will cause impurity scattering.

[0020] Preferably, the thickness of the sacrificial layer is 5 nm to 150 nm; further preferably, the thickness of the sacrificial layer is 15 nm to 150 nm.

[0021] Preferably, when the sacrificial layer is aluminum oxide, the preparation method comprises the following steps: using atomic layer deposition, introducing an aluminum source and an oxygen source, and depositing aluminum oxide as the sacrificial layer.

[0022] Preferably, the annealing temperature is 350-550° C., and the annealing time is 5-60 min; more preferably, the annealing temperature is 400-450° C., and the annealing time is 5-15 min.

[0023] Preferably, the tunneling passivation layer is silicon oxide; the electron transport layer is aluminum-doped zinc oxide; and the sacrificial layer is aluminum oxide.

[0024] A second aspect of the present invention provides a transparent conductive passivation contact structure for a silicon-based heterojunction solar cell, which is prepared by the method for preparing the transparent conductive passivation contact structure for a silicon-based heterojunction solar cell.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] In the present invention, hydrogen from the hydrogen-containing sacrificial layer diffuses toward the interface, compensating for defects in the passivation layer and dangling bonds on the silicon surface, thereby improving the contact chemical passivation effect. Simultaneously, the electron transport layer provides selective carrier transport and enhances the field-effect passivation effect.

[0027] In the present invention, due to the extremely thin thickness of the tunneling passivation layer (approximately 1-2 nm), carrier transport is achieved through the tunneling effect. The presence of a certain amount of fixed positive charge in the silicon oxide produces a certain degree of field-effect passivation. Simultaneously, the silicon oxide reduces the density of dangling bonds at the interface, providing excellent chemical passivation. Furthermore, hydrogen diffusion during annealing of the hydrogen-containing sacrificial layer compensates for interface defects or passivation layer defects, thereby improving the chemical passivation level of the tunneling passivation layer.

[0028] In the present invention, the electron transport layer material of the transparent conductive passivation contact structure is taken from wide bandgap undoped oxide materials such as aluminum-doped zinc oxide, boron-doped zinc oxide, and zinc hydroxide-doped zinc oxide, which is characterized by having a wide optical bandgap (E g >3.2eV), with relatively reduced parasitic absorption and high transparency. Selective transport materials are deposited on the n-type silicon surface to induce band bending. The band gap effect of the contact creates an asymmetric carrier transport capability, achieving selective carrier transport while also providing field-effect passivation.

[0029] In the present invention, the sacrificial layer of the transparent conductive passivation contact structure is made of a hydrogen-containing material such as aluminum oxide or silicon nitride. A thermal annealing process allows hydrogen to diffuse toward the interface, filling tunneling defects in the passivation layer and enhancing passivation. Furthermore, the sacrificial layer effectively prevents hydrogen from escaping from the contact, which could weaken passivation.

[0030] The electron transport layer and sacrificial layer in the transparent conductive passivation contact structure require a uniform, high-quality film with low impurity concentration and precisely controlled thickness and composition. Therefore, the simple, low-temperature atomic layer deposition (ALD) method is considered for thin film preparation.

[0031] In a plasma atomic layer deposition device, a complete new stack can be prepared conveniently, simply and quickly: (1) a passivating tunneling layer of silicon oxide is prepared by thermal oxidation of the silicon surface or oxygen plasma treatment by introducing oxygen or ozone into the cavity; (2) an electron transport layer of doped zinc oxide with controllable thickness and composition is prepared by the above-mentioned super-cycle method; and (3) a sufficiently thick aluminum oxide sacrificial layer is prepared by conventional atomic layer deposition cycle steps.

[0032] For the electron transport layer, atomic layer deposition (ALD) cycles control film thickness by adjusting the maximum number of deposition cycles. Thickness generally affects both passivation and contact resistance. Increasing thickness promotes more complete film formation, increases open-circuit voltage, and enhances passivation performance, but this comes with the trade-off of increased contact resistance. Conversely, decreasing thickness generally reduces contact resistance but also compromises passivation performance.

[0033] Furthermore, based on the self-limiting reaction, the film performance can be improved in the widest range and in many aspects through process adjustment. Due to the use of super-cycle process, different film state levels can be made in the same film layer to meet the design and application of the film in the device. For example, doped zinc oxide can be used as both an electron transport layer and a transparent conductive oxide layer to provide a certain carrier lateral transport capability. Among them, the former requires a good band-step matching relationship with silicon. At this time, the doping level can be adjusted to achieve the band shift of the doped zinc oxide film to achieve the best matching relationship. The latter focuses on the lateral transport square resistance of the film, specifically the carrier mobility and carrier concentration of the film. The method of increasing the carrier concentration to reduce the square resistance will lead to an increase in the parasitic absorption of the film. Therefore, more attention should be paid to the improvement of the mobility of the film, including the effective doping of impurities (reducing impurity scattering) and grain boundary problems (reducing grain boundary scattering).

[0034] In summary, the use of a simple, low-temperature atomic layer deposition (ALD) super-cycle process to prepare new stacked contacts has the following benefits: (1) The stacked structure can be completely prepared in a single process step, reducing the process difficulty and being compatible with the production line; (2) The thickness and composition of the film can be precisely controlled based on the self-limiting reaction; (3) The impurity concentration of the film is low and the quality is high; (4) It is carried out at a low temperature, with low energy consumption and avoiding thermal failure of the material device.

[0035] The structure is thermally annealed in a certain environment, and the sacrificial layer prevents hydrogen from escaping. Furthermore, during the annealing process, the contact realizes hydrogen diffusion, compensating for tunneling passivation layer defects and silicon surface dangling bonds, and improving the chemical passivation effect of the contact.

[0036] By using a chemical selective etching method, the passivation effect on the remaining structure is small after the sacrificial layer is removed.

[0037] Finally, a transparent conductive passivation contact structure consisting of an electron transport layer, a tunneling passivation layer, and an n-type silicon wafer stacked in sequence was successfully prepared. The minority carrier lifetime test showed that the structure had excellent passivation performance, and the TLM contact resistance test proved that its electrical contact performance was excellent. It is a transparent conductive passivation contact structure that can be used in high-efficiency silicon-based heterojunction solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of the transparent conductive passivation stacked structure of the silicon-based heterojunction solar cell of Example 1;

[0039] Figure 2 Schematic diagram of the transparent conductive passivation contact structure of the silicon-based heterojunction solar cell of Example 2;

[0040] Figure 3 The open circuit voltage and minority carrier lifetime test results in Example 1;

[0041] Figure 4 The TLM test results in Example 2;

[0042] Reference numerals: Figure 1 In the figure, 1-substrate, 2-tunneling passivation layer, 3-electron transport layer, 4-sacrificial layer; Figure 2 In the figure, 1-substrate, 2-tunneling passivation layer, 3-electron transport layer, 4-sacrificial layer, 5-electrode. DETAILED DESCRIPTION

[0043] The following is a further description of specific embodiments of the present invention. It should be noted that the description of these embodiments is intended to facilitate understanding of the present invention and does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0044] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are commercially available unless otherwise specified.

[0045] Example 1

[0046] This embodiment provides a method for preparing a transparent conductive passivation contact structure of a silicon-based heterojunction solar cell, which specifically includes the following steps:

[0047] As attached Figure 1 In this embodiment, an n-type silicon wafer is used as substrate 1 and texturing treatment is performed on the n-type silicon wafer. The wafer is then cleaned with standard RCA1 cleaning, i.e., cleaning with a mixed solution of ammonia water: hydrogen peroxide: deionized water = 1:1:6 (volume ratio) in a water bath at 80°C for 10 minutes to remove organic matter. The wafer is then cleaned with standard RCA2 cleaning, i.e., cleaning with a mixed solution of hydrogen chloride: hydrogen peroxide: deionized water = 1:1:6 in a water bath at 80°C for 10 minutes to remove metal ion contamination on the surface of the wafer. The wafer is finally rinsed with deionized water and blown dry with nitrogen. Deionized water cleaning steps are included in each step between the RCA cleaning steps. A silicon wafer was placed in an atomic layer deposition (ALD) chamber for plasma oxidation, with oxygen introduced for 4 seconds at a power of 80 W to obtain a silicon oxide film with a thickness of approximately 1 nm as a tunneling passivation layer 2. Atomic layer deposition was performed on the tunneling passivation layer 2 using diethylzinc as a zinc source, water as an oxygen source, and trimethylaluminum as an aluminum source. The zinc source pulse time was 80 ms, and the purge time was 12 s; the oxygen source pulse time was 80 ms, and the purge time was 12 s; and the aluminum source pulse time was 100 ms. Different reactants were alternately introduced into the reaction chamber, chemically adsorbed on the surface, and reacted to form a deposited electron transport layer film 3. The ratio of the number of times different reactants alternately enter the reaction chamber in one reaction cycle is changed, that is, the total number of reaction cycles is controlled to remain unchanged (30 cycles, one zinc source and one oxygen source for one zinc oxide cycle, here referring to 30 zinc oxide cycles, approximately 4.8nm). Aluminum-doped zinc oxide is used as the electron transport layer, and the different ratios (n) of aluminum doping of zinc oxide are changed; 250 cycles of aluminum oxide (approximately 28nm) are deposited as a sacrificial layer 4 on the electron transport layer 3 by atomic layer deposition using trimethylaluminum as the aluminum source and ultrapure water as the oxygen source; the sample is removed and placed in an annealing furnace, heated to 500°C in a forming gas environment (nitrogen:hydrogen = 95%:5%), and annealed for 30 minutes.

[0048] The open circuit voltage and minority carrier lifetime of the above structure were measured using a minority carrier lifetime tester. Figure 3 When the total number of cycles is controlled to be 100, n=5, that is, one aluminum oxide cycle is inserted after every five zinc oxide cycles, the passivation effect is the best, with a minority carrier lifetime of 683μs and an open circuit voltage of 727.2mV.

[0049] Example 2

[0050] This embodiment provides a method for preparing a transparent conductive passivation contact structure of a silicon-based heterojunction solar cell, which specifically includes the following steps:

[0051] In this embodiment, an n-type silicon wafer 1 is used as substrate 1 and texturing treatment is performed on the n-type silicon wafer. The wafer is sequentially cleaned with standard RCA1 cleaning, i.e., cleaning with a mixed solution of ammonia water: hydrogen peroxide: deionized water = 1:1:6 (volume ratio) in a water bath at 80°C for 10 minutes to remove organic matter; treated with 2% hydrofluoric acid solution for 1 minute to remove surface silicon oxide; then cleaned with standard RCA2 cleaning of the silicon wafer, i.e., cleaning with a mixed solution of hydrogen chloride: hydrogen peroxide: deionized water = 1:1:6 in a water bath at 80°C for 10 minutes to remove metal ion contamination on the silicon wafer surface; treated with 2% hydrofluoric acid solution for 1 minute to remove surface silicon oxide; finally, rinsed with deionized water and blown dry with nitrogen; deionized water cleaning steps are included in each step between the RCA cleaning steps. The silicon wafer was placed in the atomic layer deposition equipment chamber for plasma oxidation, oxygen was introduced for 4 seconds, and the power was 80W to obtain a silicon oxide film with a thickness of about 1nm as the tunneling passivation layer 2; on the tunneling passivation layer 2, diethyl zinc was used as the zinc source, water was used as the oxygen source, and trimethyl aluminum was used as the aluminum source by atomic layer deposition. The zinc source pulse time was 80ms and the purge time was 12s; the oxygen source pulse time was 80ms and the purge time was 12s; the aluminum source pulse time was 100ms; different reactants alternately entered the reaction chamber and chemically adsorbed and reacted on the surface to form a deposited electron transport layer film 3. According to Example 1, the passivation effect is best when n=5. The ratio of zinc oxide doped with aluminum was controlled to n=5, and 4 large cycles, i.e., a total of 20 zinc oxide cycles of doped zinc oxide were prepared as the electron transport layer 3 as shown in the attached figure. Figure 1 , the sample was deposited on the electron transport layer by atomic layer deposition using trimethylaluminum as the aluminum source and ultrapure water as the oxygen source, and 250 cycles of aluminum oxide (about 28nm) were deposited as a sacrificial layer 4; the four samples were placed in an annealing furnace and heated to 500℃ in a forming gas (nitrogen:hydrogen = 95%:5%) environment and annealed for 30 minutes.

[0052] The open circuit voltage and minority carrier lifetime of the above structure were measured using a minority carrier lifetime tester. The sacrificial layer 4 was selectively removed by chemical etching, and 1.2nm lithium fluoride / 300nm aluminum was thermally evaporated on the sample using a TLM mask as an electrode 5, as shown in the attached figure. Figure 2 , tested the contact resistance. The open circuit voltage of the passivated contact sample with a sacrificial layer was 679.7mV and the minority carrier lifetime was 212.53μs; the contact resistance of the electrical contact test sample was 89.3mΩ·cm -2 , TLM test results are as attached Figure 4 .

[0053] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. It is apparent to those skilled in the art that various changes, modifications, substitutions, and variations of these embodiments may be made without departing from the principles and spirit of the present invention, and the changes still fall within the scope of protection of the present invention.

Claims

1. A method for preparing a transparent conductive passivation contact structure for a silicon-based heterojunction solar cell, characterized in that: The following steps are involved: (1) Texturing the n-type silicon wafer followed by standard RCA cleaning; (2) preparing a tunnel passivation layer on one side of the cleaned n-type silicon wafer; The tunnel passivation layer is made of one or a stack of silicon oxide, aluminum oxide, and titanium oxide; (3) preparing an electron transport layer on the surface of the tunnel passivation layer; the electron transport layer is selected from one or a stack of aluminum-doped zinc oxide, boron-doped zinc oxide, and zinc hydroxide; (4) preparing a sacrificial layer on the surface of the electron transport layer; the sacrificial layer is made of aluminum oxide, silicon nitride or a stack of layers; (5) Annealing the structure obtained in step (4), and removing the sacrificial layer by etching after annealing to obtain the transparent conductive passivation contact structure of the silicon-based heterojunction solar cell.

2. The method for preparing a transparent conductive passivation contact structure for a silicon-based heterojunction solar cell according to claim 1, characterized in that: The thickness of the tunnel passivation layer is 0.3 nm to 2.5 nm.

3. The method for preparing a transparent conductive passivation contact structure for a silicon-based heterojunction solar cell according to claim 2, characterized in that: When the tunneling passivation layer is silicon oxide, the preparation method includes the following steps: placing the cleaned n-type silicon wafer into the chamber of an atomic layer deposition device for plasma oxidation to obtain the tunneling passivation layer.

4. The method for preparing a transparent conductive passivation contact structure for a silicon-based heterojunction solar cell according to claim 1, wherein: The thickness of the electron transport layer is 2nm to 200nm.

5. The method for preparing a transparent conductive passivation contact structure for a silicon-based heterojunction solar cell according to claim 4, characterized in that: When the electron transport layer is aluminum-doped zinc oxide, the preparation method includes the following steps: introducing a zinc source, an oxygen source, and an aluminum source, and different reactants enter the atomic layer deposition equipment chamber, chemically adsorb and react on the surface to form an electron transport layer.

6. The method for preparing a transparent conductive passivation contact structure for a silicon-based heterojunction solar cell according to claim 5, characterized in that: A zinc source and an oxygen source are introduced once to complete a zinc oxide cycle, and the total number of zinc oxide cycles is 10 to 250; and an aluminum oxide cycle is inserted after each 2 to 50 zinc oxide cycles are introduced.

7. The method for preparing a transparent conductive passivation contact structure for a silicon-based heterojunction solar cell according to claim 1, characterized in that: The thickness of the sacrificial layer is 5nm to 150nm.

8. The method for preparing a transparent conductive passivation contact structure for a silicon-based heterojunction solar cell according to claim 7, characterized in that: When the sacrificial layer is aluminum oxide, the preparation method includes the following steps: using an atomic layer deposition method, introducing an aluminum source and an oxygen source, and depositing aluminum oxide as the sacrificial layer.

9. The method for preparing a transparent conductive passivation contact structure for a silicon-based heterojunction solar cell according to claim 1, characterized in that: The annealing temperature is 350-550° C., and the annealing time is 5-60 minutes.

10. A transparent conductive passivation contact structure for a silicon-based heterojunction solar cell, characterized in that: The transparent conductive passivation contact structure of the silicon-based heterojunction solar cell is prepared by the preparation method of any one of claims 1 to 9.

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