An alkali-antimony compound target material, a method of making the same, and a method of using the same

Abstract

The present application relates to a kind of photoelectric cathode materials for vacuum electron source, vacuum image intensifier tube and other photoelectric conversion devices, especially relates to a kind of alkali antimony compound target material and its preparation method, use method.Solve the problem that the photoelectric performance difference of different samples in batch is big in the preparation technology of existing photoelectric cathode target material based on alkali antimony compound.The alkali antimony compound target material of the present application includes target substrate, alkali antimony compound layer deposited on the surface of target substrate, the material of alkali antimony compound layer is any one, two or three of single alkali antimony compound, double alkali antimony compound and multiple alkali antimony compound;The type of alkali antimony compound includes amorphous state, single crystal or polycrystalline state;The component ratio followed stoichiometric ratio in the synthesis of single alkali antimony compound, double alkali antimony compound and multiple alkali antimony compound, and the component ratio is within ±5% deviation range with stoichiometric ratio as center.

Description

Technical Field

[0001] This invention relates to a photocathode material for vacuum electron sources, vacuum image intensifiers and other photoelectric conversion devices, and particularly to an alkali antimony compound target material and its preparation and application methods. Background Technology

[0002] Photocathode materials used in vacuum electron sources, vacuum image intensifiers, and other photoelectric conversion devices can directly emit photoelectrons based on the external photoelectric effect after absorbing externally radiated photons. A strong electrostatic field is applied between the photocathode and the collecting anode to generate a photocurrent. Photocathode materials are classified according to their corresponding spectral response bands, such as solar-blind ultraviolet photocathodes, visible light photocathodes, and near-infrared extended photocathodes. For vacuum image intensifiers, due to their practical applications at night, their spectral response band should be extended as far into the near-infrared region as possible to >1000 nm.

[0003] Alkali antimony compounds are an extremely important class of photocathode materials. Due to the band structure and surface characteristics of their semiconductor materials, these materials have very high quantum efficiencies, ranging from 1% to 20%. The spectral range of alkali antimony compound photocathodes covers 200 to 1200 nm, and the specific material type can be selected according to the specific application scenario.

[0004] Alkali antimony compound photocathodes can be used in transparent optoelectronic devices in combination with transparent window substrates (such as fused silica substrates, sapphire substrates, CaF2 substrates, etc.), or they can be used in reflective optoelectronic devices in combination with highly conductive metallic substrates (such as Ni, Mo, Cu, Au, Ag, stainless steel, etc.). Reflective optoelectronic devices are mainly used in vacuum electronic source devices.

[0005] Currently, the growth technologies for photocathodes mainly consist of two techniques: in-situ evaporation growth and molecular beam epitaxy (MBE). MBE offers higher precision in controlling the evaporation rate of each metal source and produces films with superior crystallinity, but its low efficiency makes it suitable only for small-batch research and development, not mass production. In-situ evaporation growth uses relatively rudimentary equipment, requiring skilled engineers to monitor real-time photocurrent to determine film formation and control the evaporation rate and time of each metal source. Film formation is achieved through multiple alternating growth cycles. However, in-situ evaporation growth boasts relatively high production efficiency and is suitable for mass production.

[0006] However, existing in-situ evaporation growth processes for alkali antimony photocathodes all employ single metal sources in parallel arrays, with the metal source loading only meeting the needs of a single batch of production. Each loading is time-consuming and labor-intensive, and manual operation after vacuum breaking easily introduces contaminants. Furthermore, the vacuum chamber requires thermal degassing after loading, consuming significant process time, thus resulting in low production efficiency. Because each metal source is loaded only to meet the needs of a single batch of production, the tolerance of the metal sources is small (fluctuations in the installation position and loading amount of each metal source lead to batch-to-batch variations in the prepared alkali antimony photocathodes, resulting in significant performance fluctuations in the samples. Therefore, current methods for preparing alkali antimony photocathodes are insufficient to meet the requirements for high-efficiency, batch, standardized, and continuous production. Summary of the Invention

[0007] The purpose of this invention is to provide an alkali antimony compound target material and its preparation and application methods, in order to solve the problems of low production efficiency, easy introduction of contaminants, and large differences in photoelectric performance between different samples from different batches of existing alkali antimony compound-based photocathode target material preparation technologies.

[0008] The technical solution of the present invention is as follows:

[0009] This invention discloses an alkali antimony compound target material for fabricating photocathode devices, comprising a target substrate and an alkali antimony compound layer deposited on the surface of the target substrate. The key feature is that the material of the alkali antimony compound layer is any one, two, or three of mono-alkali antimony compounds, di-alkali antimony compounds, and poly-alkali antimony compounds.

[0010] The morphology of the alkali antimony compound includes amorphous, single crystal, or polycrystalline states;

[0011] When synthesizing the single-base antimony compound, the double-base antimony compound, and the multi-base antimony compound, the composition ratio used follows the stoichiometric ratio, with the composition ratio centered on the stoichiometric ratio and deviating within ±5%.

[0012] Furthermore, the monobasic antimony compound is any one of Cs3Sb, K3Sb, Na3Sb, and Rb3Sb; the dibasic antimony compound is any one of KCs2Sb, K2CsSb, Na2KSb, and NaK2Sb; and the polybasic antimony compound is Na2KSb:Cs3Sb.

[0013] Meanwhile, the present invention also provides a method for preparing the above-mentioned alkali antimony compound target material, which is characterized by including the following steps:

[0014] 1) Based on the pre-defined target material's alkali-antimony compound layer material, analyze the chemical composition and stoichiometry to determine the deposition sequence and thickness;

[0015] 2) Based on the chemical composition and stoichiometric ratio, prepare the constituent materials for synthesizing the required alkali antimony compound;

[0016] The constituent materials include an alkali metal source and an antimony metal source; the alkali metal source and the antimony metal source are compounds or elements;

[0017] 3) Prepare a clean target substrate with an atomically flat surface;

[0018] The target substrate is a stainless steel target substrate or a composite target substrate;

[0019] The composite target substrate is a stainless steel target substrate with a transition layer covering the deposition surface; the transition layer is an Sb layer; or the transition layer is a combination of an Sb layer and a Ni layer or a Mo layer, with the Sb layer covering the outermost layer; the thickness of the transition layer is 10 to 1000 nm.

[0020] 4) In 10 -7 ~10 -9 Under vacuum conditions, an alkali antimony compound layer of a predetermined thickness is deposited on the target substrate using the original material co-deposition growth method in the deposition sequence of step 1).

[0021] During the deposition process, the composition of the alkali antimony compound was controlled within ±5% of its stoichiometry by controlling the thermal evaporation rate and monitoring its chemical composition, crystal type and surface chemical state by XRD and XPS.

[0022] 5) The surface of the alkali antimony compound layer is flattened by mechanical pressing and plasma surface treatment, and then the shell is encapsulated to complete the preparation of the target material.

[0023] Furthermore, in step 3), a composite target substrate is selected;

[0024] Step 4) specifically involves:

[0025] Step 4.1) at 10 -7 ~10 -9 Under Pa vacuum conditions, a composite target substrate covered with an Sb layer is installed in an ultra-high vacuum cavity where the original material is co-deposited, and the target substrate is cleaned by plasma and heated to 50-200°C.

[0026] Step 4.2) Following the preset deposition sequence, the alkali metal source is thermally evaporated to react with the Sb layer on the surface of the target substrate to obtain the first deposition layer.

[0027] Step 4.3) Following the preset deposition sequence, the alkali metal source and antimony metal source are thermally evaporated to allow them to co-deposit with the first deposition layer to grow an alkali-antimony compound layer. The thermal evaporation rate of the alkali metal source and antimony metal source is kept stable, and the preset alkali-antimony compound layer is continuously deposited and grown at a growth rate of 5-10 nm / s until the thickness of the alkali-antimony compound layer reaches the preset thickness, at which point the metal source evaporation is stopped.

[0028] The preset thickness is controlled within 1 to 2 mm;

[0029] During the deposition process, by controlling the evaporation rate and monitoring its chemical composition, crystal type and surface chemical state through XRD and XPS, the evaporation rate of the metal source is adjusted in a timely manner so that the composition of the alkali antimony compound fluctuates within ±5% around its stoichiometry.

[0030] Step 4.4) Anneal the deposited target substrate and the deposited layer at 50-400℃ for 2-5 hours to obtain an alkali antimony compound layer of the preset thickness.

[0031] Meanwhile, the present invention also provides a method for using the above-mentioned alkali antimony compound target material, which is characterized by including the following steps:

[0032] S1) The target material is installed on the target material position inside the magnetron sputtering coating reaction chamber; the vacuum degree inside the magnetron sputtering coating reaction chamber is greater than 10. -7 Pa, the partial pressures of water and oxygen in the chamber are both <5×10. -8 Pa;

[0033] S2) Inert gas is introduced into the magnetron sputtering coating reaction chamber, and the gas flow rate is controlled to stabilize the vacuum level at 1-2 Pa.

[0034] S3) The target material is bombarded with plasma in the form of inert gas from step S2), and the surface of the target material is cleaned by plasma cleaning for 0.5 to 1 hour.

[0035] S4) Sputtering the target material to deposit a film until the film thickness reaches the specified thickness, then stopping to obtain a transmissive optoelectronic device, an alkaline antimony photocathode, or a reflective optoelectronic device, an alkaline antimony photocathode.

[0036] During sputtering, the RF power supply is maintained at 10–20W, and the growth rate is 0.01–0.05 nm / s. The film thickness of the alkaline antimony photocathode for transmissive optoelectronic devices is between 50 and 300 nm, and the film thickness of the alkaline antimony photocathode for reflective optoelectronic devices is between 50 and 1,000 nm.

[0037] Further, in step S1), the number of targets is two different targets; the two different targets are installed on two different target positions; the two different targets are the first target and the second target, respectively.

[0038] Step S4) specifically involves: sequentially sputtering the first target and the second target until the film thickness of the two targets reaches the specified thickness; while the first target is being sputtered, a shielding plate is used to shield the second target until the film thickness reaches the specified requirement; the first target is shielded with a shielding plate, and the second target is sputtered until the film thickness reaches the specified requirement, thus obtaining a composite transmissive optoelectronic device alkali antimony photocathode and / or a reflective optoelectronic device alkali antimony photocathode.

[0039] The beneficial effects of this invention are:

[0040] 1. This invention provides an alkali antimony compound target material, which uses an alkali antimony compound to replace the conventional discrete metal source, making the target material preparation method simple and efficient. It divides the original process of photocathode film growth and crystallization into two steps in time and space: alkali antimony compound target material preparation and photocathode film growth. This enables the alkali antimony compound photocathode to meet the requirements of high-efficiency, batch, standardized and continuous production.

[0041] 2. The present invention provides a method for preparing an alkali antimony compound target material. The method uses an alkali antimony compound to replace the conventional discrete metal source, making the target material preparation method simple and efficient. The original process of photocathode film growth and crystallization is divided into two steps in time and space: alkali antimony compound target material preparation and photocathode film growth. This enables the alkali antimony compound photocathode to meet the requirements of high-efficiency, batch, standardized and continuous production.

[0042] 3. The present invention provides an alkali antimony compound target material and its preparation and usage methods. The target material is mounted on an alkali antimony compound photocathode thin film preparation system, which can improve the preparation efficiency of the photocathode, reduce the single growth time of the alkali antimony photocathode, and meet the requirements for continuous production of photocathodes; it also improves the problems of the film layer stoichiometry deviating from the center value and the large fluctuation of photoelectric performance between batches of photocathode preparation. Attached Figure Description

[0043] Figure 1 This is a flowchart of an alkali antimony compound target and its preparation method according to the present invention;

[0044] Figure 2 This is a front view of a disc-shaped target substrate in an embodiment of a method for preparing an alkali antimony compound target according to the present invention;

[0045] Figure 3 This is a back view of a disc-shaped target substrate in an embodiment of a method for preparing an alkali antimony compound target according to the present invention.

[0046] Figure 4 This is a front view of a long strip target substrate in an embodiment of a method for preparing an alkali antimony compound target according to the present invention;

[0047] Figure 5 This is a back view of the elongated target substrate in an embodiment of the preparation method of an alkali antimony compound target of the present invention. Detailed Implementation

[0048] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings.

[0049] This invention discloses an alkali antimony compound target material for fabricating photocathode devices, comprising a target substrate and an alkali antimony compound layer deposited on the surface of the target substrate. The alkali antimony compound layer is made of any one, two, or three of mono-alkali antimony compounds, di-alkali antimony compounds, and poly-alkali antimony compounds. The morphology of the alkali antimony compound includes amorphous, single-crystal, or polycrystalline states. When synthesizing mono-alkali antimony compounds, di-alkali antimony compounds, and poly-alkali antimony compounds, the component ratios used follow stoichiometry, with deviations from the stoichiometry within ±5%. Specifically, the mono-alkali antimony compound is any one of Cs3Sb, K3Sb, Na3Sb, and Rb3Sb; the di-alkali antimony compound is any one of KCs2Sb, K2CsSb, Na2KSb, and NaK2Sb; and the poly-alkali antimony compound is Na2KSb:Cs3Sb. When synthesizing mono-alkali antimony compounds, di-alkali antimony compounds, and poly-alkali antimony compounds, the component ratios used do not strictly adhere to their stoichiometric ratios; deviations from the stoichiometric ratios within ≤±5% are acceptable. The chemical composition of the alkali antimony compound layer material should be designed based on its stoichiometric ratio (e.g., Cs3Sb 3:1, K2NaSb 2:1:1) to configure the thermal evaporation rates and fluxes of each metal source. However, due to the special characteristics of alkali antimony compounds, the prepared materials are polycrystalline and contain many defects; therefore, deviations from the stoichiometric ratios within ≤±5% are acceptable.

[0050] In the design of the aforementioned alkali-antimony compound targets, the stoichiometric ratio of the compounds in the alkali-antimony compound layer is the basis for setting the metal source heat evaporation rate and evaporation flux of the target. The stoichiometric ratio is the central value of the compounds in the synthesized alkali-antimony compound layer. Through analysis of the composition of the deposited alkali-antimony compound layer, the actual composition ratio of the compounds should fluctuate around the stoichiometric ratio value. For example, for the Cs3Sb target, its stoichiometric ratio is 3:1, and its fluctuation is Cs 2.71 Sb~Cs 3.31The Sb range is acceptable; design and analysis of other alkali antimony compound targets are omitted. Alkali antimony compound targets have many metastable phases, which continuously change with the chemical composition of the target. Heating the target substrate allows for sufficient crystallization and stabilization in the required stable phase. Specific installation and use of the alkali antimony compound target substrate: Install the stainless steel target substrate in an ultra-high vacuum chamber and complete thermal cleaning; the stainless steel target substrate has strong versatility, and a Ni or Mo layer can be further deposited on its surface to improve the adhesion between the target substrate and the target; alternatively, an Sb layer can be pre-deposited on the surface of the stainless steel target substrate, allowing the thermally evaporated alkali metal source to skip the adsorption step and react directly with the Sb layer surface to obtain the first deposited layer.

[0051] Meanwhile, the present invention provides a method for preparing the above-mentioned alkali antimony compound target material, which is described in detail below through two examples.

[0052] Example 1

[0053] The fabrication steps for growing single-alkali antimony compound targets in an ultra-high vacuum environment using a co-deposition method are as follows:

[0054] 1) Based on the pre-defined target material's alkali-antimony compound layer material, analyze the chemical composition and stoichiometry to determine the deposition sequence and thickness.

[0055] 2) Based on the chemical composition and stoichiometric ratio, prepare the constituent materials for synthesizing the required alkali antimony compound; the constituent materials include alkali metal source and antimony metal source; the alkali metal source and antimony metal source can be compounds or elements, such as compounds or elements of Li, Na, K, Cs, Rb, and Sb.

[0056] 3) Prepare a clean, atomically flat target substrate. This preparation involves shaping, surface polishing, and coating to create the alkali-antimony compound target substrate. The target substrate can be a stainless steel substrate or a composite target substrate. A composite target substrate is a stainless steel substrate with a transition layer deposited on its surface. The transition layer is an Sb layer; or a combination of an Sb layer and a Ni or Mo layer, with the Sb layer on the outermost layer. The thickness of the transition layer is 10–1000 nm. Coating the upper surface of the stainless steel target substrate with a Ni, Mo, or Sb layer improves the adhesion between the target substrate and the target. In this embodiment, a composite target substrate is selected.

[0057] The shape of the target substrate depends on the specifications and form of the target to be deposited, such as... Figure 2 and Figure 3 The front and back views of the disc-shaped target substrate shown are examples. Figure 4 and Figure 5 The front and back views of the elongated target substrate are shown below for illustration. In this embodiment, the inner diameter of the disc-shaped target substrate is 75 mm, and the thickness is 0.25 mm. Figure 2The shaded area represents the actual target location. Figure 3 The back view shows two mounting positions (the side thickness portion is not shown); the front is nanoscale flat for depositing an alkali antimony compound layer, while the back of the target substrate should be designed with the mounting structure based on subsequent mounting conditions. Figure 4 and Figure 5 The medium-length strip target substrate has a total length of 100mm and a height of 10mm. The front side is nanoscale flat and is used for depositing an alkali antimony compound layer. The length of the deposition area is 95mm. The back side is designed with two mounting positions.

[0058] In other embodiments, the length of the elongated target substrate can be between 50 and 100 mm, and the width can be between 10 and 40 mm, with a typical value of 100 mm in length and 10 mm in width; the inner diameter of the disc-shaped target substrate is between 10 and 100 mm, with typical inner diameter values ​​of 20 mm, 40 mm, 50 mm, and 80 mm; and the thickness of both is between 5 and 20 mm.

[0059] 4) Using the original material co-deposition growth method, deposit an alkali antimony compound layer of a predetermined thickness on the target substrate in the deposition sequence of step 1).

[0060] 4.1) In 10 -7 ~10 -9 Under ultra-high vacuum conditions, a composite target substrate covered with an Sb layer was installed in an ultra-high vacuum cavity for co-deposition of the original material. The target substrate was then cleaned using plasma and heated to 50–200°C. The partial pressures of water and oxygen were both brought to stable preset values ​​(<5 × 10⁻⁶). -8 Pa).

[0061] 4.2) Following a preset deposition sequence, an alkali metal source (such as metal Cs) is thermally evaporated to allow the alkali metal to react directly with the Sb layer on the target substrate surface to obtain a first deposition layer (such as a Cs3Sb layer). The first deposition layer is then irradiated with a preset light source, as the Cs3Sb layer itself is a photocathode, and its photocurrent changes can be measured.

[0062] 4.3) Following a preset deposition sequence, the alkali metal source and antimony metal source are thermally evaporated to allow them to co-deposit with the first deposition layer to grow an alkali-antimony compound layer. The thermal evaporation rate of the alkali metal source and antimony metal source is kept stable, and the preset alkali-antimony compound layer is continuously deposited and grown at a growth rate of 5-10 nm / s until the thickness of the alkali-antimony compound layer reaches the preset thickness (1.5 mm). At this point, the metal source evaporation is stopped. In other embodiments, the preset thickness can be controlled within 1-2 mm.

[0063] During the deposition process, by controlling the evaporation rate and monitoring its chemical composition, crystal type and surface chemical state through XRD and XPS, the evaporation rate of the metal source is adjusted in a timely manner so that the composition of the alkali antimony compound fluctuates within ±5% around its stoichiometry. For example, the optimal composition ratio for the Cs3Sb layer is 3:1.

[0064] 4.4) Anneal the deposited target substrate and the deposited layer at 50–400°C for 2–5 hours to obtain an alkali antimony compound layer of a predetermined thickness.

[0065] 5) The surface of the alkali antimony compound layer is flattened by mechanical pressing and plasma surface treatment, and then the shell is encapsulated to complete the preparation of the target material.

[0066] Example 2

[0067] The growth of dual-alkali antimony compound targets using a co-deposition method in an ultra-high vacuum environment includes the following steps:

[0068] The composite target substrate (as described above) and target encapsulation shell are used; other required alkali antimony compound target preparation conditions are the same as in Example 1.

[0069] The difference lies in the co-deposition growth of the alkali-antimony target. By heating and thermally evaporating the Na and K sources of the alkali metal compound, the alkali metal reacts directly with the Sb layer on the target surface to obtain the first deposited layer, Na2KSb. Further thermal evaporation of the Na, K, and Sb sources causes a co-deposition reaction on the first deposited layer, continuing the growth of the Na2KSb alkali-antimony compound layer. This process continues until the target thickness reaches a predetermined thickness (1.5 mm), although in other embodiments it can be 1–2 mm. After annealing at a target substrate temperature of 50–400°C for 2–5 hours, the predetermined thickness of the alkali-antimony compound layer is obtained. Following plasma cleaning of the alkali-antimony compound layer, it is then planarized and packaged.

[0070] During the co-deposition growth of the dual-alkali antimony compound layer, its chemical composition was analyzed and monitored by XRD and XPS. The evaporation rate of each metal source was adjusted in a timely manner to make the composition of the alkali antimony compound fluctuate within ±5% around its stoichiometric ratio (e.g., the optimal composition ratio for the Na2KSb layer is 2:1:1).

[0071] Furthermore, this invention also provides a method for using the aforementioned alkali antimony compound target. The alkali antimony compound target proposed in this invention can be used to fabricate both reflective and transmissive photocathode devices. These are described in detail below through Examples 3 and 4.

[0072] Example 3

[0073] S1) The target material is installed on the target material position inside the magnetron sputtering coating reaction chamber; the vacuum degree inside the magnetron sputtering coating reaction chamber is less than 10. -7Pa, the partial pressures of water and oxygen in the chamber are both <5×10. -8 Pa.

[0074] There are two methods for mounting alkali antimony compound targets in the magnetron sputtering coating reaction chamber: fixed mounting and rotary mounting. Fixed mounting means that the disc target is fixed during the film formation process, which is suitable for experimental samples and small-batch production. Rotary mounting means that the strip target rotates at a certain angular rate during the film formation process, which is suitable for large-scale production.

[0075] S2) Inert gas (such as Ar) is introduced into the magnetron sputtering coating reaction chamber, and the gas flow rate is controlled to stabilize the vacuum at 1-2 Pa.

[0076] S3) The target material is bombarded with plasma in the form of inert gas from step S2), and the surface of the target material is cleaned by plasma for 0.5 to 1 hour before use.

[0077] S4) Sputtering the target material to deposit a film until the film thickness reaches the specified thickness, then stopping to obtain a transmissive optoelectronic device, an alkaline antimony photocathode, or a reflective optoelectronic device, an alkaline antimony photocathode.

[0078] During sputtering, the RF power supply is maintained at 10–20 W, and the growth rate is 0.01–0.05 nm / s. The film thickness of the alkali antimony photocathode for transmissive optoelectronic devices is between 50 and 300 nm, while the film thickness of the alkali antimony photocathode for reflective optoelectronic devices is between 50 and 1000 nm. After magnetron sputtering, the alkali antimony compound target is packaged for later use.

[0079] Example 4

[0080] In a magnetron sputtering coating system, two types of alkali-antimony compound targets can be used in combination, namely the first target and the second target. The installation of the alkali-antimony compound target and the magnetron sputtering coating conditions are the same as in Example 3. A shielding plate is placed between the photocathode substrate and the alkali-antimony compound target, and then the magnetron sputtering coating RF power supply is turned on, and the plasma bombards the surface of the alkali-antimony compound target. When the first target is sputtered (such as the Na2KSb target in the example above), the second target (such as the Cs3Sb target in the example above) is shielded by a shielding plate. When the first target deposits a film thickness of about 150-300 nm on the photocathode substrate, the shielding plate shields the first target. At this time, the second target begins to be sputtered and deposited. The deposition of the second target film thickness is stopped after 1-10 nm. After the magnetron sputtering of the two alkali antimony compound targets is completed, they are packaged for use. This process can produce composite alkali antimony photocathode films (such as the second-generation Na2KSb:Cs3Sb photocathode). During the evaporation process of the second alkali antimony compound target, a Cs source can be appropriately introduced to further activate the surface of the composite photocathode and reduce the surface affinity.

[0081] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure.

Claims

1. A method for preparing an alkali antimony compound target, wherein the alkali antimony compound target is used to prepare a photocathode device, comprising a target substrate and an alkali antimony compound layer deposited on the surface of the target substrate, wherein the material of the alkali antimony compound layer is any one, two, or three of mono-alkali antimony compounds, di-alkali antimony compounds, and poly-alkali antimony compounds; The morphology of the alkali antimony compound includes amorphous, single crystal, or polycrystalline states; When synthesizing the mono-base antimony compound, di-base antimony compound, and poly-base antimony compound, the composition ratio used follows the stoichiometric ratio, with the deviation from the stoichiometric ratio within ±5%. The monobasic antimony compound is any one of Cs3Sb, K3Sb, Na3Sb, and Rb3Sb; The dual-base antimony compound is any one of KCs2Sb, K2CsSb, Na2KSb, and NaK2Sb; The polyalkali antimony compound is Na2KSb:Cs3Sb; Its features are, Includes the following steps: 1) Based on the pre-defined target material's alkali-antimony compound layer material, analyze the chemical composition and stoichiometry to determine the deposition sequence and thickness; 2) Based on the chemical composition and stoichiometric ratio, prepare the constituent materials for synthesizing the required alkali antimony compound; The constituent materials include an alkali metal source and an antimony metal source; the alkali metal source and the antimony metal source are compounds or elements; 3) Prepare a clean target substrate with an atomically flat surface; The target substrate is a stainless steel target substrate or a composite target substrate; The composite target substrate is a stainless steel target substrate with a transition layer covering the deposition surface; the transition layer is an Sb layer; or the transition layer is a combination of an Sb layer and a Ni layer or a Mo layer, with the Sb layer covering the outermost layer; the thickness of the transition layer is 10~1000 nm. 4) In 10 -7 ~10 -9 Under vacuum conditions, an alkali antimony compound layer of a predetermined thickness is deposited on the target substrate using the original material co-deposition growth method in the deposition sequence of step 1). During the deposition process, the composition of the alkali antimony compound was controlled within ±5% of its stoichiometry by controlling the thermal evaporation rate and monitoring its chemical composition, crystal type and surface chemical state by XRD and XPS. 5) The surface of the alkali antimony compound layer is flattened by mechanical pressing and plasma surface treatment, and then the shell is encapsulated to complete the preparation of the target material.

2. The method for preparing an alkali antimony compound target according to claim 1, characterized in that, In step 3), a composite target substrate is selected; Step 4) specifically involves: Step 4.1) at 10 -7 ~10 -9 Under Pa vacuum conditions, a composite target substrate covered with an Sb layer is installed in an ultra-high vacuum cavity where the original material is co-deposited, and the target substrate is cleaned by plasma and heated to 50~200℃. Step 4.2) Following the preset deposition sequence, the alkali metal source is thermally evaporated to react with the Sb layer on the surface of the target substrate to obtain the first deposition layer. Step 4.3) Following the preset deposition sequence, the alkali metal source and antimony metal source are thermally evaporated to allow them to co-deposit with the first deposition layer to grow an alkali antimony compound layer. The thermal evaporation rate of the alkali metal source and antimony metal source is kept stable, and the preset alkali antimony compound layer is continuously deposited and grown at a growth rate of 5~10 nm / s until the thickness of the alkali antimony compound layer reaches the preset thickness, at which point the metal source evaporation is stopped. The preset thickness is controlled within 1~2 mm; During the deposition process, by controlling the evaporation rate and monitoring its chemical composition, crystal type and surface chemical state through XRD and XPS, the evaporation rate of the metal source is adjusted in a timely manner so that the composition of the alkali antimony compound fluctuates within ±5% around its stoichiometry. Step 4.4) Anneal the deposited target substrate and the deposited layer at 50~400 ℃ for 2~5 hours to obtain an alkali antimony compound layer of the preset thickness.

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