A high-density czt target and a method for manufacturing the same

Abstract

The application belongs to the technical field of target material preparation, and discloses a preparation method of high-density CZT target material, which comprises the following steps: firstly, zinc powder, cadmium telluride powder, tellurium powder and silver powder are mixed according to a mass ratio of 9-15:65:20-30:0.01-0.03 to obtain powder one; secondly, the powder one is sintered, crushed and sieved to obtain powder two with a particle size of 80-120 mesh and powder three with a particle size of 180-220 mesh; thirdly, the powder two and the powder three are mixed and homogenized according to a mass ratio of 0.9-1.1:1 to obtain powder four; fourthly, the powder four is loaded into a mold and pressed to obtain a CZT green body; and finally, the CZT green body is vacuum hot-pressed and cooled to obtain the high-density CZT target material. The silver powder is mixed with the tellurium powder, the cadmium powder and the zinc powder, sintered, crushed, sieved and hot-pressed to obtain the CZT target material, and the prepared target material has a density of 99%. In addition, the application further discloses the high-density CZT target material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of target material preparation, in particular to a high-density CZT target material and a preparation method thereof. BACKGROUND

[0002] At present, solar cells are divided into two types, namely crystalline silicon solar cells and thin film solar cells, and cadmium zinc telluride (CZT) is an indispensable part of compound thin film solar cells in thin film solar cells. Compound semiconductor materials are mostly direct bandgap semiconductor materials, have a high light absorption coefficient, and generally have a large bandgap, and their radiation resistance is significantly higher than that of silicon solar cells. The bandgap of cadmium zinc telluride is about 1.57 eV, and the bandgap of cadmium telluride is 1.4 eV; CZT has excellent optical properties, making CZT have a broad prospect in the fields of thin film solar and detectors.

[0003] CdZnTe and CdTe thin film detectors have excellent X-ray detection and imaging performance, and have the advantages of large-area preparation and low cost. CZT is a high-resistivity semiconductor material, and the formation of an adjustable interface contact characteristic by doping with metal is of great significance to the performance improvement of the detector. The present application obtains a CZT ingot by sintering Ag powder, tellurium powder, cadmium powder and zinc powder, and then obtains a CZT target material through crushing, sieving and hot-pressing sintering. The prepared target material has a density of 99%, and the process is simple and easy to operate, saving cost

[0004] Chinese patent application 201610836897.0 discloses a preparation method of cadmium zinc telluride target material, comprising the following steps:

[0005] A) uniformly mixing cadmium telluride powder, zinc telluride powder and cuprous telluride powder to obtain a mixed powder;

[0006] B) vacuum hot-pressing sintering the mixed powder to obtain a cadmium zinc telluride target material.

[0007] The scheme uses cadmium telluride powder, zinc telluride powder and cuprous telluride powder as raw materials for preparing cadmium zinc telluride target material, and obtains cadmium zinc telluride target material by vacuum hot-pressing method. The preparation method is simple and easy to operate, and is easy to industrialize production. The cadmium zinc telluride target material prepared by this method has high density and good mechanical properties;

[0008] As can be seen from the above scheme, the raw materials used in the above scheme are cadmium telluride powder, zinc telluride powder and cuprous telluride powder. Since the final product is cadmium zinc telluride target material, the cuprous telluride powder in the above raw materials is more likely to be used as an additive;

[0009] Chinese patent application 202211019717.1 discloses a production process for doped cadmium telluride, comprising the following steps:

[0010] Step S1, according to the stoichiometric ratio, the tellurium powder, cadmium powder and doped element powder are mixed uniformly to obtain a mixture;

[0011] Step S2, the mixture of step S1 is synthesized into a doped cadmium telluride preform under inert gas protection at 400-500 DEG C under normal pressure;

[0012] Step S3, the preform is placed in a vacuum environment, heated to 750-800 DEG C for a period of time, then heated to 1090-1150 DEG C for a period of time; after heating, cooling, a doped cadmium telluride is obtained.

[0013] The scheme uses tellurium powder, cadmium powder, and doped element powder as raw materials for doped cadmium telluride, and directly synthesizes doped cadmium telluride, which is low in cost;

[0014] Meanwhile, the scheme adopts a low-temperature preforming and high-temperature melting heat treatment system, and the prepared doped cadmium telluride is uniform in composition and has no segregation phenomenon;

[0015] And the preparation method is relatively simple, easy to control, and conducive to large-scale production. More importantly, although the scheme attempts to dope multiple elements in the production process of cadmium telluride, it is found that the composition of the doped cadmium telluride is uniform and has no segregation phenomenon.

[0016] The problem to be solved by the present scheme is: how to provide a new preparation method of high relative density cadmium zinc telluride target material. SUMMARY

[0017] The purpose of the present application is to provide a preparation method for producing high relative density cadmium zinc telluride target material different from the prior art.

[0018] To achieve the above-mentioned purpose, the present application discloses a preparation method of high density CZT target material, comprising the following steps:

[0019] Step 1: zinc powder, cadmium telluride powder, tellurium powder and silver powder are mixed according to the mass ratio of 9-15:65:20-30:0.01-0.03 to obtain powder one;

[0020] Step 2: powder one is sintered, crushed and sieved to obtain powder two with a particle size of 80-120 mesh and powder three with a particle size of 180-220 mesh;

[0021] Step 3: powder two and powder three prepared in step 2 are mixed and homogenized according to the mass ratio of 0.9-1.1:1 to obtain powder four, and then the powder four is loaded into a mold and pressed to obtain a CZT green body;

[0022] Step 4: the CZT blank prepared in step 3 is vacuum hot-pressed and cooled to obtain a high-density CZT target.

[0023] Preferably, the median particle size of the zinc powder is 50-100 mesh, the median particle size of the cadmium telluride powder is 100-150 mesh, the median particle size of the tellurium powder is 250-325 mesh, and the median particle size of the silver powder is 250-325 mesh.

[0024] Preferably, the sintering process in step 2 is specifically as follows: the powder is placed in a sintering furnace and heated to 400-800℃ at a heating rate of 5-10℃ / min and kept for 1-2h.

[0025] Preferably, step 3 is specifically as follows: the powder two and the powder three prepared in step 2 are mixed and homogenized according to a mass ratio of 0.9-1.1:1 to obtain a powder four, and then the powder four is loaded into a mold and pressure-bonded at a pressure of 20-30T for 15-25min to obtain a CZT blank.

[0026] Preferably, step 4 is specifically as follows: the CZT blank prepared in step 3 is placed into a vacuum hot-pressing furnace, first heated to 700-750℃ at a heating rate of 8-10℃ / min and kept for 20-40min, then the pressure in the vacuum hot-pressing furnace is increased to 40-50Mpa, and kept for 70-110min, after the keeping and pressure-keeping is completed, the furnace is cooled and a protective gas is introduced into the vacuum hot-pressing furnace, and after cooling to room temperature, the furnace is taken out to obtain a high-density CZT target.

[0027] In addition, the application also discloses a high-density CZT target prepared by the above-mentioned preparation method of a high-density CZT target, and the relative density of the high-density CZT target is greater than or equal to 99%.

[0028] The application has the beneficial effects that: the application mixes silver powder, tellurium powder, cadmium powder and zinc powder, sintering to obtain CZT, and then crushing, sieving and hot-pressing sintering to obtain a CZT target, the prepared target has a density of 99%, the process is simple and has strong operability, and cost is saved. DETAILED DESCRIPTION

[0029] The application will be described clearly and completely in combination with the embodiments of the application, and in the description of the application, it should be noted that, if the specific conditions are not indicated in the embodiments, the conventional conditions or the conditions recommended by the manufacturers are adopted. If the manufacturers of the reagents or instruments are not indicated, the conventional products that can be purchased in the market are adopted.

[0030] Example 1

[0031] Step 1: zinc powder, cadmium telluride powder, tellurium powder and silver powder with median particle sizes of 73 mesh, 132 mesh, 313 mesh and 296 mesh respectively were mixed in a mass ratio of 9:65:25.99:0.01 to obtain powder one;

[0032] Step 2: powder one was placed into a sintering furnace and heated to 400℃ at a heating rate of 5℃ / min and kept for 1h, then crushed and sieved to obtain powder two with a particle size of 80 mesh and powder three with a particle size of 180 mesh;

[0033] Step 3: powder two and powder three prepared in step 2 were mixed in a mass ratio of 0.9:1 and homogenized to obtain powder four, then powder four was loaded into a mold and sintered at a pressure of 20T for 15min to obtain a CZT green body;

[0034] Step 4: the CZT green body prepared in step 3 was placed into a vacuum hot pressing furnace, first heated to 700℃ at a heating rate of 8℃ / min and kept for 20min, then the pressure in the vacuum hot pressing furnace was increased to 40Mpa, and kept for 70min, after the keeping and pressure maintaining was completed, the furnace was cooled and a protective gas was introduced into the vacuum hot pressing furnace, and after cooling to room temperature, the furnace was taken out to obtain a high-density CZT target material.

[0035] Example 2

[0036] Step 1: zinc powder, cadmium telluride powder, tellurium powder and silver powder with median particle sizes of 52 mesh, 105 mesh, 252 mesh and 255 mesh respectively were mixed in a mass ratio of 15:65:30:0.03 to obtain powder one;

[0037] Step 2: powder one was placed into a sintering furnace and heated to 800℃ at a heating rate of 10℃ / min and kept for 2h, then crushed and sieved to obtain powder two with a particle size of 120 mesh and powder three with a particle size of 220 mesh;

[0038] Step 3: powder two and powder three prepared in step 2 were mixed in a mass ratio of 1.1:1 and homogenized to obtain powder four, then powder four was loaded into a mold and sintered at a pressure of 30T for 25min to obtain a CZT green body;

[0039] Step 4: the CZT green body prepared in step 3 was placed into a vacuum hot pressing furnace, first heated to 750℃ at a heating rate of 10℃ / min and kept for 40min, then the pressure in the vacuum hot pressing furnace was increased to 50Mpa, and kept for 110min, after the keeping and pressure maintaining was completed, the furnace was cooled and a protective gas was introduced into the vacuum hot pressing furnace, and after cooling to room temperature, the furnace was taken out to obtain a high-density CZT target material.

[0040] Example 3

[0041] Step 1: zinc powder, cadmium telluride powder, tellurium powder and silver powder with median particle sizes of 98 mesh, 148 mesh, 323 mesh and 322 mesh respectively were mixed in a mass ratio of 10:65:20:0.01 to obtain powder one;

[0042] Step 2: powder one was placed in a sintering furnace and heated to 600℃ at a heating rate of 8℃ / min and kept for 1.5h, then crushed and sieved to obtain powder two with a particle size of 100 mesh and powder three with a particle size of 100 mesh;

[0043] Step 3: powder two and powder three prepared in step 2 were mixed in a mass ratio of 1:1 and homogenized to obtain powder four, and then powder four was loaded into a mold and pressed at a pressure of 25T for 20min to obtain a CZT green body;

[0044] Step 4: the CZT green body prepared in step 3 was placed in a vacuum hot pressing furnace, first heated to 725℃ at a heating rate of 9℃ / min and kept for 30min, then the pressure in the vacuum hot pressing furnace was increased to 45Mpa, and then kept for 90min, after the heat preservation and pressure keeping was completed, the furnace was cooled down and a protective gas was introduced into the vacuum hot pressing furnace, and after cooling to room temperature, the furnace was taken out to obtain a high-density CZT target material.

[0045] Comparative Example 1

[0046] The same as Example 1, except that in step 1, silver telluride powder with the same particle size was used instead of silver powder, and the molar amount of silver in the silver telluride powder was the same as the molar amount of silver in the silver powder.

[0047] Comparative Example 2

[0048] The same as Example 1, except that in step 1, cadmium telluride powder with a particle size less than 100 mesh, zinc telluride powder with a particle size less than 100 mesh, 313 mesh tellurium powder and 296 mesh silver powder were mixed, and the molar ratio of cadmium telluride, zinc telluride and tellurium was 1.8:1:0.3, and the mass ratio of silver powder to the total mass of cadmium telluride, zinc telluride and tellurium was 0.01:99.99.

[0049] Comparative Example 3

[0050] The same as Example 1, except that in step 1, cuprous telluride powder with the same particle size was used instead of silver powder, and the molar amount of copper in the cuprous telluride powder was the same as the molar amount of silver in the silver powder.

[0051] Comparative Example 4

[0052] The same as Example 1, except that in step 3, the mass ratio of powder two and powder three was 0.5:1.

[0053] Comparative Example 5

[0054] The same as example 1, except that in step 3, the mass ratio of powder two and powder three is 1.5:1.

[0055] Comparative example 6

[0056] Step 1: zinc powder, cadmium telluride powder, tellurium powder and silver powder with median particle sizes of 73 mesh, 132 mesh, 313 mesh and 296 mesh respectively are mixed in a mass ratio of 9:65:25.99:0.01 to obtain powder one;

[0057] Step 2: powder one is put into a sintering furnace and heated to 400℃ at a heating rate of 5℃ / min and kept for 1-2h, crushed and sieved to obtain powder two with a particle size of 130 mesh;

[0058] Step 3: powder two prepared in step 2 is loaded into a mold and sintered at a pressure of 20T for 15min to obtain a CZT green body;

[0059] Step 4: the CZT green body prepared in step 3 is put into a vacuum hot pressing furnace, first heated to 700℃ at a heating rate of 8℃ / min and kept for 20min, then the pressure in the vacuum hot pressing furnace is increased to 40Mpa, and kept for 70min, the furnace is cooled down and a protective gas is introduced into the vacuum hot pressing furnace, and after cooling to room temperature, the furnace is taken out to obtain a CZT target material.

[0060] Comparative example 7

[0061] The same as example 6, except that in step 1, cuprous telluride powder with the same particle size is used instead of silver powder, and the molar amount of copper in the cuprous telluride powder is the same as the molar amount of silver in the silver powder.

[0062] Performance test:

[0063] The relative density of the CZT target materials prepared in the examples and comparative examples is detected by the Archimedes drainage method, and the results are shown in Table 1:

[0064] Table 1

[0065] Group Relative density Example 1 99.1％ Example 2 99.4％ Example 3 99.7％ Comparative Example 1 92.8％ Comparative Example 2 91.3％ Comparative Example 3 91.8％ Comparative Example 4 89.8％ Comparative Example 5 90.5％ Comparative Example 6 91.6％ Comparative Example 7 87.2％

[0066] Result analysis:

[0067] 1. As can be seen from example 1 and comparative example 1, when silver telluride powder is used instead of silver powder, although comparative example 1 can still maintain a relative density of more than 90%, the relative density still decreases to a certain extent, and as can be seen from comparative examples 2 and 3, when cadmium telluride, zinc telluride and tellurium are used as main raw materials or when cuprous telluride is used instead of silver powder, the relative density of the target material decreases to different degrees, therefore, we believe that only when zinc powder, cadmium telluride powder, tellurium powder and silver powder are used together, the relative density of the target material can be effectively improved;

[0068] 2. As can be seen from Example 1 and Comparative Examples 4-6, when the ratio between small-diameter powder II and large-diameter powder III is significantly adjusted, the relative density of the target material decreases significantly. We believe that the ratio between powder II and powder III disclosed in Examples 1-3 can more significantly improve the particle size of the powder.

[0069] 3. As can be seen from Examples 1, 1, 6, and 7, when Comparative Example 7 uses cuprous telluride powder instead of silver powder and presses the green blank using fraction II with a particle size of 130 mesh in step 3, the relative density of the target material decreases to 87.2%. Meanwhile, the relative densities of the target materials in Comparative Examples 1 and 6 are 92.8% and 91.6%, respectively, which are 5.6% and 4.4% higher than those in Comparative Example 7. In contrast, the relative density of the target material in Example 1 reaches 99.1%. We believe that the reason why Example 1 achieves such a superior relative density is the result of the synergistic effect between silver powder and fraction II and fraction III with different particle sizes. The reason is that the improvement effect of Example 1 compared to Comparative Example 7 exceeds the improvement effect on relative density that can be achieved by simply superimposing Comparative Examples 1 and 6.

[0070] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method of producing a high-density CZT target material, characterized by, The method comprises the following steps: Step 1: zinc powder, cadmium telluride powder, tellurium powder and silver powder are mixed according to a mass ratio of 9-15:65:20-30:0.01-0.03 to obtain powder one; Step 2: powder one is sintered, crushed and sieved to obtain powder two with a particle size of 80-120 mesh and powder three with a particle size of 180-220 mesh; Step 3: powder two and powder three prepared in step 2 are mixed and homogenized according to a mass ratio of 0.9-1.1:1 to obtain powder four, and then powder four is loaded into a mold and pressed to obtain a CZT green body; Step 4: the CZT green body prepared in step 3 is vacuum hot-pressed and cooled to obtain a high-density CZT target material; The median particle size of the zinc powder is 50-100 mesh, the median particle size of the cadmium telluride powder is 100-150 mesh, the median particle size of the tellurium powder is 250-325 mesh, and the median particle size of the silver powder is 250-325 mesh.

2. The method of claim 1, wherein the method further comprises: The sintering process of step 2 is specifically as follows: powder one is placed in a sintering furnace and heated to 400-800℃ at a heating rate of 5-10℃ / min and kept for 1-2h.

3. The method of claim 1, wherein the method further comprises: Step 3 is specifically as follows: powder two and powder three prepared in step 2 are mixed and homogenized according to a mass ratio of 0.9-1.1:1 to obtain powder four, and then powder four is loaded into a mold and pressed at a pressure of 20-30T for 15-25min to obtain a CZT green body.

4. The method of claim 1, wherein the method further comprises: Step 4 is specifically as follows: the CZT green body prepared in step 3 is placed in a vacuum hot-pressing furnace, first heated to 700-750℃ at a heating rate of 8-10℃ / min and kept for 20-40min, then the pressure in the vacuum hot-pressing furnace is increased to 40-50MPa, and then kept for 70-110min, after the keeping and pressure maintaining are completed, the furnace is cooled and a protective gas is introduced into the vacuum hot-pressing furnace, and after cooling to room temperature, the furnace is taken out to obtain a high-density CZT target material.

5. A high density CZT target material, characterized in that, The high-density CZT target material prepared by the method of any one of claims 1-4 has a relative density greater than or equal to 99%.