Co-sputtering doped zinc telluride film and preparation method and application thereof

Abstract

The invention relates to a co-sputtering doped zinc telluride thin film and a preparation method and application thereof, and relates to the technical field of solar thin film cells, and the preparation method comprises the following steps: installing a ZnTe target material and a doped target material on a magnetron sputtering system; preparing a co-sputtering doped zinc telluride film on the substrate by adopting a double-target magnetron co-sputtering method; doped elements in the co-sputtering doped zinc telluride thin film comprise at least one of Sb and N. The invention solves the technical problems of attenuation and degradation of battery performance caused by diffusion of a copper dopant in the existing zinc telluride doping technology and the technical problems of complex preparation process, non-uniform doping and difficulty in realizing accurate control of low doping concentration in the traditional doping method.

Description

Technical Field

[0001] The present invention relates to the technical field of solar thin-film batteries, and in particular to a co-sputtered doped zinc telluride film and a preparation method and application thereof. Background Art

[0002] Cadmium telluride (CdTe) thin film solar cells have long attracted great attention due to their low-cost manufacturing process and good device performance. As of 2024, the laboratory conversion efficiency of CdTe power generation glass has reached 34%. However, in actual production applications, the formation of a stable ohmic back contact is still a key issue and one of the biggest challenges in the preparation of high-efficiency CdTe photovoltaic cells. ZnTe is used as a transition layer material between CdTe thin film and electrode. Due to its wide energy gap, low electron affinity, high photoelectric conversion efficiency and ability to achieve heavy doping, it has become a very promising optoelectronic functional material. In order to enhance the intrinsic p-type conductivity of ZnTe, doping with acceptor impurities is a good way to improve the ohmic contact. The transition layer formed by ZnTe:Cu can form a heavily doped p+ region in the battery material to allow tunneling transmission at the interface. However, copper is a fast-migrating impurity in cadmium telluride (CdTe) that may cause degradation of cell performance, and further diffusion of dopants during solar cell operation may lead to degradation of cell performance, which limits the use of copper-containing back contact materials. In addition, traditional doping methods make it difficult to achieve uniform distribution of dopants in the material, which may lead to large performance differences in local areas. Excessive or uneven copper doping may form recombination centers, increase the recombination probability of electron-hole pairs, and thus reduce the photoelectric conversion efficiency or luminescence efficiency of the material. In addition, the preparation process of the doped target is complicated and it is easy to introduce unwanted impurities, affecting the performance of the material. For situations where extremely low doping concentrations are required, precise control is difficult to achieve. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a co-sputtering doped zinc telluride film and a preparation method and application thereof.

[0004] In a first aspect, the present invention provides a method for preparing a co-sputtering doped zinc telluride film, the preparation method comprising the following steps:

[0005] Installing the ZnTe target and the doped target on a magnetron sputtering system;

[0006] Co-sputtered doped zinc telluride thin films were prepared on substrates by using a dual-target magnetron co-sputtering method.

[0007] The doping element in the co-sputtered doped zinc telluride film includes at least one of Sb and N.

[0008] Furthermore, the substrate includes at least one of a silicon wafer and glass.

[0009] Further, when the doping element in the co-sputtered doped zinc telluride film is Sb, the general structural formula of the co-sputtered doped zinc telluride film is [ZnTe(a) / Sb(b)], wherein a is the doping ratio of the ZnTe target material in the film, which is 98.5% to 99.99%; b is the doping ratio of the Sb target material in the film, which is 0.2% to 1.5%; the step of preparing the co-sputtered doped zinc telluride film on the substrate by a dual-target magnetron co-sputtering method includes a first preliminary preparation and a first dual-target magnetron co-sputtering coating:

[0010] The first preliminary preparation includes:

[0011] (1) Place the ZnTe target and the Sb target on the No. 1 and No. 2 target positions of the sputtering instrument respectively, fix the substrate on the transmission line, close the external vent valve, and seal the chamber;

[0012] (2) Turn on the vacuum gauge and mechanical pump to evacuate the chamber until the vacuum reaches 2×10 -6 mbar or below, start the molecular pump and evacuate to 4×10 -3 mbar, the chamber temperature rises to 160°C;

[0013] (3) Setting the DC sputtering power of ZnTe and Sb targets to 800 W;

[0014] (4) High-purity Ar gas was used as the sputtering gas, the Ar gas flow rate was set to 430 SCCM, and the sputtering gas pressure was 0.2 Pa;

[0015] The first dual-target magnetron co-sputtering coating comprises:

[0016] The sputtering rate of the ZnTe target is 4.2 s / nm, and the sputtering rate of the Sb target is 14.2 s / nm to 30 min / nm. The proportion of the target in the [ZnTe(a) / Sb(b)] film and the sputtering thickness are controlled by the sputtering rate.

[0017] Further, when b is 0.2%, the sputtering rate is 30 min / nm.

[0018] Furthermore, controlling the proportion of the target material in the [ZnTe(a) / Sb(b)] film and the sputtering thickness by sputtering speed specifically includes the following processes: (1) turning on the DC sputtering power supply of the ZnTe target, sputtering the ZnTe film for a time corresponding to the set thickness, and turning off the DC sputtering power supply of the ZnTe target after the sputtering is completed; (2) while implementing (1), turning on the DC sputtering power supply of the Sb target, sputtering the Sb film for a time corresponding to the set thickness, and turning off the DC sputtering power supply of the Sb target after the sputtering is completed.

[0019] Further, when the doping element in the co-sputtered doped zinc telluride film is Sb, the general structural formula of the co-sputtered doped zinc telluride film is [ZnTe(a) / Sb(b) / N(c)], wherein a is the doping ratio of the ZnTe target in the film, which is 98.5% to 99.99%; b is the doping ratio of the Sb target in the film, which is 0.2% to 1.5%; c is the doping ratio of N in the film, which is 1% to 4%; the step of preparing the co-sputtered doped zinc telluride film on the substrate by a dual-target magnetron co-sputtering method includes a second preliminary preparation and a second dual-target magnetron co-sputtering coating;

[0020] The second preliminary preparation includes:

[0021] (1) Place the ZnTe target and the Sb target on the No. 1 and No. 2 target positions of the sputtering instrument respectively, fix the substrate on the transmission line, close the external vent valve, and seal the chamber;

[0022] (2) Turn on the vacuum gauge and mechanical pump to evacuate the chamber until the vacuum reaches 2×10 -6 mbar or below, start the molecular pump and evacuate to 4×10 -3 mbar, the chamber temperature rises to 160°C;

[0023] (3) Setting the DC sputtering power of ZnTe and Sb targets to 1000 W;

[0024] (4) Use high-purity Ar gas and N2 as sputtering gas, the Ar gas flow rate is set to 430 SCCM, the N2 gas flow rate is set to 20-43 SCCM, and the sputtering pressure is 0.2 Pa. The N element doping ratio is controlled by the sputtering gas ventilation ratio;

[0025] The second dual-target magnetron co-sputtering coating comprises:

[0026] The sputtering rate of the ZnTe target is 4.2 s / nm, and the sputtering rate of the Sb target is 14.2 s / nm to 30 min / nm. The proportion of the target in the [ZnTe(a) / Sb(b) / N(c)] film and the sputtering thickness are controlled by the sputtering rate.

[0027] Further, when the doping element in the co-sputtered doped zinc telluride film is Sb, the general structural formula of the co-sputtered doped zinc telluride film is [ZnTe(a) / N(c)], wherein a is the doping ratio of the ZnTe target material in the film, which is 98.5% to 99.99%; c is the doping ratio of N in the film, which is 1% to 4%; the step of preparing the co-sputtered doped zinc telluride film on the substrate by a dual-target magnetron co-sputtering method includes a third preliminary preparation and a third dual-target magnetron co-sputtering coating;

[0028] The third preliminary preparation includes:

[0029] (1) Place the ZnTe target on target position 1 of the sputtering instrument, fix the glass chip on the transmission line, close the external vent valve, and seal the cavity;

[0030] (2) Turn on the vacuum gauge and mechanical pump to evacuate the chamber until the vacuum reaches 2×10 -6 mbar or above, start the molecular pump and evacuate to 4×10 -3 mbar, the chamber temperature rises to 160°C;

[0031] (1) Set the DC sputtering power of the ZnTe target to 1000 W;

[0032] (2) High-purity nitrogen was used as the sputtering gas, the N2 gas flow rate was set to 30 SCCM (the nitrogen doping content was the percentage of the introduced gas), and the sputtering pressure was 0.2 Pa;

[0033] The third dual-target magnetron co-sputtering coating comprises:

[0034] The sputtering rate of the ZnTe target is 4.2 s / nm, and the sputtering rate of the Sb target is 14.2 s / nm to 30 min / nm. The proportion of the target in the [ZnTe(a) / N(c)] film and the sputtering thickness are controlled by the sputtering rate.

[0035] In a second aspect, the present invention provides a co-sputtered doped zinc telluride film, wherein the co-sputtered doped zinc telluride film is prepared by the preparation method described in any one of the first aspects, and the thickness of the co-sputtered doped zinc telluride film is 7-10 nm.

[0036] In a third aspect, the present invention provides a use of the co-sputtered doped zinc telluride thin film described in any one of the first aspect and any one of the second aspect in the preparation of solar thin-film cells.

[0037] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art:

[0038] The embodiment of the present invention provides a co-sputtering doped zinc telluride film and a preparation method and application thereof. The present invention provides a method for preparing a doped zinc telluride film by a co-sputtering process, and applies it to the field of photoelectric thin film materials. Considering the stability of the transition layer and preventing defects from forming in the absorption layer, a co-sputtering doped zinc telluride film that is completely free of copper is selected for preparation. Antimony, nitrogen, and antimony / nitrogen doped zinc telluride films are prepared respectively by a co-sputtering method with a simple process and precise control of the doping composition and uniformity, in order to prepare a zinc telluride film with excellent photoelectric properties, providing a new process for improving the performance of cadmium telluride solar cells. Specifically:

[0039] 1) The present invention can conveniently change the proportion of different target material components in the plated film layer by controlling the working current of the target material respectively to change its sputtering rate, or obtain zinc telluride films with different doping concentrations and different doping elements by changing the sputtering power of the Sb target material and the nitrogen gas flow rate. In addition, by gradually increasing the sputtering rate of one target and correspondingly reducing the sputtering rate of the other target, a gradient film with a uniform transition ratio of the two target material components can also be prepared. This method for preparing a doped cadmium telluride film can well control the distribution uniformity and controllability of different elemental components in the prepared film layer. Improve the photoelectric conversion efficiency of the zinc telluride transition layer.

[0040] 2) The first aspect of the present invention selects to prepare a completely copper-free co-sputtered doped zinc telluride film out of consideration for the stability of the transition layer and the prevention of defects in the absorption layer. Group V elements (nitrogen, boron, arsenic, antimony) have also been attempted for doping p-type zinc telluride. Studies have shown that doping with metal elements antimony and non-metallic elements such as nitrogen and arsenic can effectively improve the optical and electrical properties of thin film materials. Moreover, nitrogen and antimony can form shallow acceptor energy levels in zinc telluride due to their beneficial low ionization energy, and are used as efficient dopants. Therefore, the present invention selects antimony and nitrogen as doping elements. The doping concentration is controlled by sputtering power, and the doping element is controlled by target material selection. Solve the problems of degradation of battery performance, attenuation of photoelectric conversion efficiency, and carrier recombination caused by dopant diffusion.

[0041] 3) The second aspect of the present invention provides a method for preparing a co-sputtered doped zinc telluride film by co-sputtering, using antimony and zinc telluride as targets. A co-sputtered doped zinc telluride film is prepared on a substrate by a dual-target magnetron co-sputtering method. At the end of the sputtering process, nitrogen doping or nitrogen co-doping in a nitrogen atmosphere can be provided to prepare a zinc telluride film. Doping elements such as antimony and nitrogen can be added to the lattice to reduce the band gap of the zinc telluride film, generate an acceptor level in the band gap, increase the carrier concentration, and reduce the resistivity, thereby increasing the open circuit voltage and short circuit current density of the solar cell.

[0042] 4) The doped zinc telluride has high uniformity. During the co-sputtering process, the target material is sputtered at the same time, and the doping elements can be more evenly distributed in the film or material. More uniform electrical properties can be achieved.

[0043] 5) The co-sputtering process can more accurately control the content and proportion of doping elements, thereby optimizing the performance of the material. The sputtering process is simple and mature. Compared with some complex traditional doping methods, the co-sputtering process is relatively simple and easy to achieve large-scale production.

[0044] 6) By selecting nitrogen and antimony elements of group V for doping, the free carrier concentration of doped zinc telluride is increased. The band gap of zinc telluride film will decrease, and the doping elements can be added to the lattice to produce an acceptor level in the band gap, increase the carrier concentration, and improve the open circuit voltage and short circuit current density of the solar cell.

[0045] 7) The preparation and synthesis method of the embodiment of the present invention is simple, the raw materials are abundant, and it has the advantage of low cost and can be widely used. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0048] Figure 1 It is a schematic structural diagram of a co-sputtering device when a co-sputtered doped zinc telluride film is prepared on a substrate by a dual-target magnetron co-sputtering method in the present invention.

[0049] Figure 2 The diagram is a schematic structural diagram of the introduction of doping gas when preparing a co-sputtered doped zinc telluride film on a substrate by a dual-target magnetron co-sputtering method in the present invention.

[0050] Figure 3 It is a schematic diagram of preparing antimony-doped zinc telluride thin film on a substrate by using a dual-target magnetron co-sputtering method in the present invention.

[0051] Figure 4 Schematic diagram of the preparation of antimony / nitrogen-doped zinc telluride thin film on a substrate using a dual-target magnetron co-sputtering method in the present invention.

[0052] Figure 1 In the middle: 1 is the top plate; 2 is the target material; 3 is the substrate; 4 is the heater; 5 is the bottom plate; 6 is the cooling water; 7 is the vacuum pump.

[0053] Figure 2 Middle: 8 is a gas pipeline; 9 is a diaphragm valve; 10 is a pressure switch. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0056] In a first aspect, the present invention provides a method for preparing a co-sputtering doped zinc telluride film, the preparation method comprising the following steps:

[0057] Installing the ZnTe target and the doped target on a magnetron sputtering system;

[0058] Co-sputtered doped zinc telluride thin films were prepared on substrates by using a dual-target magnetron co-sputtering method.

[0059] The doping element in the co-sputtered doped zinc telluride film includes at least one of Sb and N.

[0060] The present invention provides a method for preparing a doped zinc telluride film by a co-sputtering process, and applies the method to the field of photoelectric thin film materials. Considering the stability of the transition layer and preventing defects from forming in the absorption layer, a co-sputtering doped zinc telluride film completely free of copper is selected for preparation. Antimony, nitrogen, and antimony / nitrogen doped zinc telluride films are prepared respectively by a co-sputtering method with a simple process and accurate control of doping components and uniformity, so as to prepare a zinc telluride film with excellent photoelectric properties, and provide a new process for improving the performance of cadmium telluride solar cells.

[0061] In some specific embodiments, the preparation method includes the following steps: (1) installing the main ZnTe and the doped target material Sb on a magnetron sputtering system. (2) placing a substrate (such as a silicon wafer, glass, etc.) on the anode and ensuring that the substrate surface is clean and the substrate temperature is (25°C-350°C) (3) introducing gases such as argon and nitrogen after evacuation. For the preparation of zinc telluride films that require N doping, the nitrogen-argon ratio is 1:10, and the gas flow rate (10-50sccm) and working pressure (0.5-5Pa) are adjusted to control the atmosphere during the sputtering process. (4) applying electric and magnetic fields to control the trajectory of electrons and improve sputtering efficiency. The sputtered atoms are deposited on the surface of the substrate to form a thin film. The film growth during the sputtering process can be adjusted by controlling parameters such as sputtering time, power, and gas pressure to adjust the thickness and quality of the film. Pure antimony doping, pure nitrogen doping, or nitrogen / antimony co-doping can be selected to prepare co-sputtered doped zinc telluride films.

[0062] In a second aspect, the present invention provides a co-sputtered doped zinc telluride film, wherein the co-sputtered doped zinc telluride film is prepared by the preparation method described in any one of the first aspects, and the thickness of the co-sputtered doped zinc telluride film is 7-10 nm.

[0063] In a third aspect, the present invention provides a use of the co-sputtered doped zinc telluride thin film described in any one of the first aspect and any one of the second aspect in the preparation of solar thin-film cells.

[0064] It should be noted that the components and raw materials involved in the co-sputtering doped zinc telluride film and its preparation method and application provided in the embodiments of the present invention, unless otherwise specified or specified, can be directly commercially available products or homemade using existing public preparation methods; at the same time, the steps and parameters involved, unless otherwise specified or specified, can be carried out according to the existing co-sputtering doped zinc telluride film processing technology or directly adopt the following methods: Figure 1 and Figure 2 The present invention is not described in detail in the document.

[0065] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0066] Example 1

[0067] The ZnTe doped Sb film prepared in this embodiment has a total thickness of about 7-10 nm and a general structural formula of [ZnTe(a) / Sb(b)], where a is the doping ratio of the ZnTe target in the film, and b is the doping ratio of the Sb target in the film. Figure 3 As shown, the preparation method thereof adopts the following steps:

[0068] 1. Clean the surface and back of the glass chip to remove dust particles, organic and inorganic impurities:

[0069] (1) Ultrasonic cleaning of the glass chip with deionized water for 20 minutes;

[0070] (2) Take out the glass chip, blow dry the surface and back with high-purity N2, and place it in a drying oven for later use.

[0071] 2. Preliminary preparation of [ZnTe(a) / Sb(b)] doped thin films by magnetron sputtering:

[0072] (1) Place the ZnTe target and the Sb target on the No. 1 and No. 2 target positions of the sputtering instrument respectively, fix the glass chip on the transmission line, close the external vent valve, and seal the cavity;

[0073] (2) Turn on the vacuum gauge and mechanical pump to evacuate the chamber until the vacuum reaches 2×10 -6 mbar or below, start the molecular pump and evacuate to 4×10 -3 mbar, the chamber temperature rises to 160°C;

[0074] (3) Setting the DC sputtering power of ZnTe and Sb targets to 800 W;

[0075] (4) High-purity Ar gas was used as the sputtering gas, the Ar gas flow rate was set to 430 SCCM, and the sputtering gas pressure was set to 0.2 Pa.

[0076] 3. Use the coating monitoring program to coat the film. The required sputtering thickness can be achieved by the sputtering time. The sputtering speed of the ZnTe target is 4.2s / nm, and the sputtering speed of the Sb target is 14.2s / nm~30min / nm.

[0077] The ratio of the target material in the [ZnTe(a) / Sb(b)] film is controlled by the sputtering rate. When b is 0.2%, the sputtering rate is 30min / nm.

[0078] (1) Turn on the DC sputtering power supply of the ZnTe target (target No. 1), sputter the ZnTe film according to the set thickness and sputtering time. After the sputtering is completed, turn off the DC sputtering power supply of the ZnTe target.

[0079] (2) While implementing (1), turn on the DC sputtering power supply of the Sb target (target No. 2), sputter the Sb film according to the set thickness and sputtering time. After sputtering, turn off the DC sputtering power supply of the Sb target.

[0080] 4. End of sputtering:

[0081] (1) When the film reaches the desired thickness or quality, stop the sputtering process.

[0082] (2) Turn off the electric and magnetic fields and stop the flow of gas.

[0083] (3) Remove the substrate from the magnetron sputtering system.

[0084] Example 2

[0085] The doping elements of the ZnTe doped film prepared in this embodiment are Sb and N, and the film thickness is 7-10nm. Figure 4 shown.

[0086] The preparation method comprises the following steps:

[0087] 1. Clean the surface and back of the glass chip to remove dust particles, organic and inorganic impurities:

[0088] (1) Ultrasonic cleaning of the glass chip with deionized water for 20 minutes;

[0089] (2) Take out the glass chip, blow dry the surface and back with high-purity N2, and place it in a drying oven for later use.

[0090] 2. Preliminary preparation of [ZnTe(c) / Sb(d) / N(e)] doped thin films by magnetron sputtering:

[0091] (1) Place the ZnTe target and the Sb target on the No. 1 and No. 2 target positions of the sputtering instrument respectively, fix the glass chip on the transmission line, close the external vent valve, and seal the cavity;

[0092] (2) Turn on the vacuum gauge and mechanical pump to evacuate the chamber until the vacuum reaches 2×10 -6 mbar or below, start the molecular pump and evacuate to 4×10 -3 mbar, the chamber temperature rises to 160°C;

[0093] (3) Setting the DC sputtering power of ZnTe and Sb targets to 1000 W;

[0094] (4) High-purity Ar gas and N2 are used as sputtering gases, the Ar gas flow rate is set to 430 SCCM, the N2 gas flow rate is set to 20-43 SCCM, and the sputtering pressure is 0.2 Pa. The N element doping ratio is controlled by the sputtering gas ventilation ratio (the nitrogen doping content is the percentage of the gas).

[0095] 3. Use the coating monitoring program to coat the film. The required sputtering thickness can be achieved by the sputtering time. The sputtering speed of the ZnTe target is 4.2s / nm, and the sputtering speed of the Sb target is 14.2s / nm-30min / nm. The proportion of the target in the [ZnTe(a) / Sb(b)] film is controlled by the sputtering speed. When b is 0.2%, the sputtering speed is 30min / nm.

[0096] (1) Turn on the DC sputtering power supply of the ZnTe target (target No. 1), sputter the ZnTe film according to the set thickness and sputtering time. After the sputtering is completed, turn off the DC sputtering power supply of the ZnTe target.

[0097] (2) While implementing (1), turn on the DC sputtering power supply of the Sb target (target No. 2), sputter the Sb film according to the set sputtering thickness and the corresponding sputtering time. After the sputtering is completed, turn off the DC sputtering power supply of the ZnTe target and the DC sputtering power supply of the Sb target at the same time.

[0098] 4. End of sputtering:

[0099] (1) When the film reaches the desired thickness or quality, stop the sputtering process.

[0100] (2) Turn off the electric and magnetic fields and stop the flow of gas.

[0101] (3) Remove the substrate from the magnetron sputtering system.

[0102] Example 3

[0103] The ZnTe film prepared in this embodiment is doped with nitrogen and has a total thickness of 7-10 nm.

[0104] 1. Clean the surface and back of the glass chip to remove dust particles, organic and inorganic impurities:

[0105] (1) Ultrasonic cleaning of the glass chip with deionized water for 20 minutes;

[0106] (2) Take out the glass chip, blow dry the surface and back with high-purity N2, and place it in a drying oven for later use.

[0107] 2. Preliminary preparation for preparing ZnTe doped thin films by magnetron sputtering:

[0108] (1) Place the ZnTe target on target position 1 of the sputtering instrument, fix the glass chip on the transmission line, close the external vent valve, and seal the cavity;

[0109] (2) Turn on the vacuum gauge and mechanical pump to evacuate the chamber until the vacuum reaches 2×10 -6 mbar or above, start the molecular pump and evacuate to 4×10 -3mbar, the chamber temperature rises to 160°C;

[0110] (1) Set the DC sputtering power of the ZnTe target to 1000 W;

[0111] (2) High-purity nitrogen was used as the sputtering gas, the N2 gas flow rate was set to 20-43 SCCM, and the sputtering pressure was 0.2 Pa.

[0112] 2. Use the coating monitoring program for coating. The required sputtering thickness can be achieved by the sputtering time. The sputtering speed of the ZnTe target is 4.2s / nm. After sputtering, turn off the DC sputtering power supply of the target.

[0113] Comparative Example 1

[0114] The ZnTe film prepared in this comparative example has no element doping and has a total thickness of 7-10 nm.

[0115] 1. Clean the surface and back of the glass chip to remove dust particles, organic and inorganic impurities:

[0116] (1) Ultrasonic cleaning of the glass chip with deionized water for 20 minutes;

[0117] (2) Take out the glass chip, blow dry the surface and back with high-purity N2, and place it in a drying oven for later use.

[0118] 2. Preliminary preparation for preparing ZnTe doped thin films by magnetron sputtering:

[0119] (1) Place the ZnTe target on target position 1 of the sputtering instrument, fix the glass chip on the transmission line, close the external vent valve, and seal the cavity;

[0120] (2 Turn on the vacuum gauge and mechanical pump to evacuate the chamber until the vacuum reaches 2×10 -6 mbar or above, start the molecular pump and evacuate to 4×10 -3 Below mbar;

[0121] (3) Setting the DC sputtering power of the ZnTe target to 1000 W;

[0122] (4) High-purity argon was used as the sputtering gas, the Ar gas flow rate was set to 30 SCCM, and the sputtering gas pressure was set to 0.2 Pa.

[0123] 3. Use the coating monitoring program for coating. The required sputtering thickness can be achieved by the sputtering time. The sputtering speed of the ZnTe target is 4.2s / nm. After sputtering, turn off the DC sputtering power supply of the target.

[0124] 4. End of sputtering:

[0125] (1) When the film reaches the desired thickness or quality, stop the sputtering process.

[0126] (2) Turn off the electric and magnetic fields and stop the flow of gas.

[0127] (3) Remove the substrate from the magnetron sputtering system.

[0128] Test Case

[0129] The films obtained in the above examples and comparative examples were subjected to performance tests.

[0130] The test results are shown in Table 1-3.

[0131] Table 1 Comparative data of doping with different antimony contents in Example 1

[0132]

[0133] Table 2 Comparative data of different nitrogen content doping in Example 2

[0134]

[0135] Table 3 Comparative data of different embodiments

[0136]

[0137] It can be seen from Table 1 that from sample 1 to sample 4, as the Sb element doping content increases from 0.50% to 1.50%, the maximum power P, short-circuit current Isc, and conversion efficiency generally show an upward trend, and the short-circuit resistance is relatively reduced. When the Sb element doping content is 1.5%, the maximum power reaches 280W, which is 6.1W higher than the photovoltaic module made of undoped zinc telluride, and the conversion efficiency increases by 0.21%. It is speculated that due to the differences in radius and valence between antimony ions and zinc ions, the doping of antimony elements may affect the crystal structure of zinc telluride and increase the conductivity of the material. By improving the generation and transport of carriers, the electrical parameters such as resistance and conductivity of the material are affected. It should be noted that when the doping content increases to a certain extent, the performance improvement is no longer obvious, and even a slight decrease occurs. This may be because as the antimony doping content increases, the zinc telluride lattice will form severe lattice distortion, affecting the electrochemical performance.

[0138] It can be seen from Table 2 that the maximum power P of the solar cell module gradually increases from 274.02W at 1% doping to 279.86W at 3% doping, which shows that the doping of N element helps to improve the power output to a certain extent. However, the power slightly decreases to 279.18W at 4% doping. This shows that increasing the N doping content within a certain range can improve the maximum power, short-circuit current, conversion efficiency, and reduce the series resistance. However, when the doping content is too high (4%), the excessively high doping concentration may lead to adverse effects such as increased crystal structure defects and intensified carrier recombination.

[0139] It can be seen from Table 3 that when the Sb doping content of the ZnTe target is 1.5% and the N doping content is 3%, the maximum power of the cadmium telluride component increases by 7.7W. ZnTe doped with antimony and nitrogen elements exhibits enhanced p-type conductivity. In addition, after doping with antimony, the conductivity of the zinc telluride target, which originally had poor conductivity, is improved to a certain extent. The electron transmission path inside the doped zinc telluride target is improved, and electrons are more likely to move in the material, which reduces the resistivity of the target and improves the component power. The reduction in resistivity and component power indicate that element-doped zinc telluride is effective doping.

[0140] Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0141] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a co-sputtering doped zinc telluride film, characterized in that: The preparation method comprises the following steps: Installing the ZnTe target and the doped target on a magnetron sputtering system; Co-sputtered doped zinc telluride thin films were prepared on substrates by using a dual-target magnetron co-sputtering method. The doping element in the co-sputtered doped zinc telluride film includes at least one of Sb and N.

2. The method for preparing a co-sputtering doped zinc telluride thin film according to claim 1, characterized in that: The substrate includes at least one of a silicon wafer and glass.

3. The method for preparing a co-sputtering doped zinc telluride thin film according to claim 1, characterized in that: When the doping element in the co-sputtered doped zinc telluride film is Sb, the structural formula of the co-sputtered doped zinc telluride film is [ZnTe(a) / Sb(b)], wherein a is the doping ratio of the ZnTe target material in the film, which is 98.50% to 99.99%; b is the doping ratio of the Sb target material in the film, which is 0.2% to 1.5%. The step of preparing the co-sputtered doped zinc telluride film on a substrate by a dual-target magnetron co-sputtering method includes a first preliminary preparation and a first dual-target magnetron co-sputtering coating: The first preliminary preparation includes: (1) Place the ZnTe target and the Sb target on the No. 1 and No. 2 target positions of the sputtering instrument respectively, fix the substrate on the transmission line, close the external vent valve, and seal the chamber; (2) Turn on the vacuum gauge and mechanical pump to evacuate the chamber until the vacuum reaches 2×10 -6 mbar or below, start the molecular pump and evacuate to 4×10 -3 mbar, the chamber temperature rises to 160°C; (3) Setting the DC sputtering power of ZnTe and Sb targets to 800 W; (4) High-purity Ar gas was used as the sputtering gas, the Ar gas flow rate was set to 430 SCCM, and the sputtering gas pressure was 0.2 Pa; The first dual-target magnetron co-sputtering coating comprises: The sputtering rate of the ZnTe target is 4.2 s / nm, and the sputtering rate of the Sb target is 14.2 s / nm to 30 min / nm. The proportion of the target in the [ZnTe(a) / Sb(b)] film and the sputtering thickness are controlled by the sputtering rate.

4. The method for preparing a co-sputtering doped zinc telluride thin film according to claim 3, characterized in that: When b is 0.2%, the sputtering rate is 30 min / nm.

5. The method for preparing a co-sputtering doped zinc telluride thin film according to claim 3, characterized in that: Controlling the proportion of target material in the [ZnTe(a) / Sb(b)] film and the sputtering thickness by sputtering speed specifically includes the following processes: (1) turning on a DC sputtering power supply of a ZnTe target, sputtering a ZnTe film according to a set sputtering time of a corresponding thickness, and turning off the DC sputtering power supply of the ZnTe target after the sputtering is completed; (2) While implementing (1), turn on the DC sputtering power supply of the Sb target, sputter the Sb film according to the set thickness and sputtering time. After the sputtering is completed, turn off the DC sputtering power supply of the Sb target.

6. The method for preparing a co-sputtering doped zinc telluride thin film according to claim 1, characterized in that: When the doping elements in the co-sputtered doped zinc telluride film are Sb and N, the general structural formula of the co-sputtered doped zinc telluride film is [ZnTe(a) / Sb(b) / N(c)], wherein a is the doping ratio of the ZnTe target material in the film, which is 98.50% to 99.99%; b is the doping ratio of the Sb target material in the film, which is 0.2% to 1.5%; c is the doping ratio of N in the film, which is 1% to 4%. The step of preparing the co-sputtered doped zinc telluride film on the substrate by a dual-target magnetron co-sputtering method includes a second preliminary preparation and a second dual-target magnetron co-sputtering coating; The second preliminary preparation includes: (1) Place the ZnTe target and the Sb target on the No. 1 and No. 2 target positions of the sputtering instrument respectively, fix the substrate on the transmission line, close the external vent valve, and seal the chamber; (2) Turn on the vacuum gauge and mechanical pump to evacuate the chamber until the vacuum reaches 2×10 -6 mbar or below, start the molecular pump and evacuate to 4×10 -3 mbar, the chamber temperature rises to 160°C; (3) Setting the DC sputtering power of ZnTe and Sb targets to 1000 W; (4) High-purity Ar gas and N2 were used as sputtering gases, the Ar gas flow rate was set to 430 SCCM, the N2 gas flow rate was set to 20-43 SCCM, and the sputtering pressure was 0.2 Pa; the N element doping ratio was controlled by the sputtering gas ventilation ratio; The second dual-target magnetron co-sputtering coating comprises: The sputtering rate of the ZnTe target is 4.2 s / nm, and the sputtering rate of the Sb target is 14.2 s / nm to 30 min / nm. The proportion of the target in the [ZnTe(a) / Sb(b) / N(c)] film and the sputtering thickness are controlled by the sputtering rate.

7. The method for preparing a co-sputtering doped zinc telluride thin film according to claim 1, characterized in that: When the doping element in the co-sputtered doped zinc telluride film is N, the structural formula of the co-sputtered doped zinc telluride film is [ZnTe(a) / N(c)], wherein a is the doping ratio of the ZnTe target material in the film, which is 98.50% to 99.99%; b is the doping ratio of N in the film, which is 1% to 4%. The step of preparing the co-sputtered doped zinc telluride film on a substrate by a dual-target magnetron co-sputtering method includes a third preliminary preparation and a third dual-target magnetron co-sputtering coating; The third preliminary preparation includes: (1) Place the ZnTe target on target position 1 of the sputtering instrument, fix the glass chip on the transmission line, close the external vent valve, and seal the cavity; (2) Turn on the vacuum gauge and mechanical pump to evacuate the chamber until the vacuum reaches 2×10 -6 When the pressure reaches 4×10 mbar or above, start the molecular pump and evacuate to 4×10 -3 mbar, the chamber temperature rises to 160°C; (1) Set the DC sputtering power of the ZnTe target to 1000 W; (2) High-purity nitrogen was used as the sputtering gas, the N2 gas flow rate was set to 20-43 SCCM (the nitrogen doping content was the percentage of the introduced gas), and the sputtering pressure was 0.2 Pa; The third dual-target magnetron co-sputtering coating comprises: The sputtering rate of the ZnTe target is 4.2 s / nm, and the sputtering rate of the Sb target is 14.2 s / nm to 30 min / nm. The proportion of the target in the [ZnTe(a) / N(c] film and the sputtering thickness are controlled by the sputtering rate.

8. A co-sputtered doped zinc telluride film, characterized in that: The co-sputtered doped zinc telluride film is prepared by the preparation method according to any one of claims 1 to 7, and the thickness of the co-sputtered doped zinc telluride film is 7-10 nm.

9. Use of the co-sputtered doped zinc telluride film according to any one of claims 1 to 8 in the preparation of solar thin-film cells.

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