Gallium-holmium-doped tin oxide target and method for producing the same

Abstract

The application discloses a gallium-holmium-doped tin oxide target material and a preparation method thereof. The preparation method comprises the following steps: mixing gallium oxide, holmium oxide and tin oxide; the obtained mixture comprises 0.2% to 2% of gallium oxide, 0.1% to 1% of holmium oxide and 97% to 99.7% of tin oxide in terms of mass percentage; then, a dispersing agent, a binder and water are added; and granulation, mould pressing, cold isostatic pressing and sintering are performed to obtain the gallium-holmium-doped tin oxide target material. The gallium-holmium-doped tin oxide target material has the advantages of excellent electric conductivity and high visible light transmittance, and when the gallium-holmium-doped tin oxide target material is used for a transparent conductive film, the carrier concentration and the band gap of the film can be adjusted, so that the electric conductivity and the visible light transmittance of the film are effectively improved, and the gallium-holmium-doped tin oxide target material has a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of target material production technology, specifically relating to a gallium-holmium doped tin oxide target and its preparation method. Background Technology

[0002] In the field of heterojunction solar cells (HJT), indium oxide (IO) is commonly used as the transparent conductive layer (TCO). However, the high price and large price fluctuations of IO hinder its application and promotion in HJT solar cell devices. Compared to IO, tin dioxide (SOD) is an n-type semiconductor material with a wide bandwidth, possessing characteristics such as high temperature resistance, corrosion resistance, and excellent high-temperature conductivity, and is relatively inexpensive. It also exhibits unique photoelectric and gas-sensitive properties, making it widely used in gas-sensitive components, semiconductor devices, and solar cells. However, currently available tin oxide sputtering targets, when used as TCO materials, suffer from low density and poor conductivity, often failing to achieve optimal photoelectric performance. Therefore, obtaining a tin oxide sputtering target with excellent conductivity, high visible light transmittance, and low cost is crucial for the widespread application of tin oxide sputtering targets. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a gallium-holmium doped tin oxide target with excellent conductivity and high visible light transmittance and its preparation method.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0005] A method for preparing a gallium-holmium-doped tin oxide target includes the following steps: (1) Gallium oxide, holmium oxide and tin oxide are mixed to obtain a mixed powder; by mass percentage, gallium oxide is 0.2% to 2%, holmium oxide is 0.1% to 1%, and tin oxide is 97% to 99.7%; (2) Mix the mixed powder, dispersant, binder and water obtained in step (1) to obtain a slurry; (3) The slurry obtained in step (2) is granulated, molded, and cold isostatically pressed in sequence to obtain the target blank; (4) The target blank obtained in step (3) is sintered to obtain a gallium-holmium doped tin oxide target.

[0006] In a further improvement to the above preparation method, in step (3), the molding pressure is 60MPa to 100MPa.

[0007] In a further improvement to the above preparation method, in step (3), the pressure of the cold isostatic pressing is 200MPa to 400MPa.

[0008] In a further improvement to the above preparation method, in step (4), the sintering temperature is 1200℃~1450℃, the sintering time is 5h~9h, and the sintering is carried out under sealed conditions.

[0009] In a further improvement to the above preparation method, in step (1), the gallium oxide has a particle size of 50 nm to 150 nm and a purity of 4N; the holmium oxide has a particle size of 50 nm to 150 nm and a purity of 4N; and the tin oxide has a particle size of 50 nm to 150 nm and a purity of 4N.

[0010] In a further improvement to the above preparation method, in step (2), the amount of dispersant added is 0.2% to 5% of the total mass of the mixed powder; the amount of binder added is 0.2% to 5% of the total mass of the mixed powder; and the solid content of the slurry is 50% to 70%.

[0011] In a further improvement to the above preparation method, the dispersant is ammonium polyacrylate and the binder is polyvinyl butyral.

[0012] In a further improvement to the above preparation method, in step (3), the granulation is spray granulation.

[0013] As a general technical concept, the present invention also provides a gallium-holmium-doped tin oxide target prepared by the above-described preparation method.

[0014] Compared with the prior art, the advantages of the present invention are as follows: This invention provides a method for preparing gallium-holmium-doped tin oxide target materials. Using gallium oxide, holmium oxide, and tin oxide as raw materials, the method comprises, by mass percentage, 0.2%–2% gallium oxide, 0.1%–1% holmium oxide, and 97%–99.7% tin oxide. A dispersant and binder are then added, followed by granulation, molding, cold isostatic pressing, and sintering to obtain a gallium-holmium-doped tin oxide target material with excellent conductivity and high visible light transmittance. The preparation method of this invention, by limiting the proportions of gallium oxide, holmium oxide, and tin oxide, can adjust the carrier concentration and bandgap of the thin film, thereby effectively improving the conductivity and visible light transmittance of the transparent conductive film prepared from the tin oxide target material, and has excellent application prospects. Detailed Implementation

[0015] The present invention will be further described below with reference to specific preferred embodiments, but this does not limit the scope of protection of the present invention. All materials and instruments used in the following embodiments are commercially available.

[0016] Example 1: A method for preparing a gallium-holmium-doped tin oxide target according to the present invention includes the following steps: (1) Mix 0.2 kg gallium oxide powder, 0.1 kg holmium oxide powder, 9.7 kg tin oxide powder, 0.2 kg ammonium polyacrylate dispersant, 0.2 kg polyvinyl butyral binder and 4.6 kg water evenly to obtain a slurry; wherein the particle size of gallium oxide powder is 50 nm to 150 nm and the purity is 4N, the particle size of holmium oxide powder is 50 nm to 150 nm and the purity is 4N, and the particle size of tin oxide powder is 50 nm to 150 nm and the purity is 4N.

[0017] (2) The slurry obtained in step (1) is subjected to spray granulation, molding and cold isostatic pressing in sequence to obtain the target blank; wherein the pressure of molding is 80MPa and the pressure is controlled at 200MPa during the cold isostatic pressing process.

[0018] (3) Under normal pressure, in a closed system without gas flow, the target blank obtained in step (2) is sintered at 1450°C for 5 hours to obtain a gallium-holmium-doped tin oxide target. In this embodiment, the relative density of the gallium-holmium-doped tin oxide target is 98.5%.

[0019] A transparent conductive film with a thickness of 800 nm to 900 nm was obtained by depositing gallium-holmium-doped tin oxide target, as prepared in this embodiment, onto a glass substrate using radio frequency sputtering deposition. The resistivity of the transparent conductive film was measured to be 0.9 mΩ·cm, and its visible light transmittance at a wavelength of 650 nm was 87%.

[0020] Example 2: A method for preparing a gallium-holmium-doped tin oxide target according to the present invention includes the following steps: (1) Mix 0.02 kg gallium oxide powder, 0.01 kg holmium oxide powder, 9.97 kg tin oxide powder, 0.05 kg ammonium polyacrylate dispersant, 0.05 kg polyvinyl butyral binder and 4.9 kg water evenly to obtain a slurry; wherein the particle size of gallium oxide powder is 50 nm to 150 nm and the purity is 4N, the particle size of holmium oxide powder is 50 nm to 150 nm and the purity is 4N, and the particle size of tin oxide powder is 50 nm to 150 nm and the purity is 4N.

[0021] (2) The slurry obtained in step (1) is subjected to spray granulation, molding and cold isostatic pressing in sequence to obtain the target blank; wherein the pressure of molding is 80MPa and the pressure is controlled at 400MPa during the cold isostatic pressing process.

[0022] (3) Under normal pressure, in a closed system without gas flow, the target blank obtained in step (2) is sintered at 1270°C for 8 hours to obtain a gallium-holmium-doped tin oxide target. In this embodiment, the relative density of the gallium-holmium-doped tin oxide target is 98.5%.

[0023] A transparent conductive film with a thickness of 500 nm to 600 nm was obtained by depositing gallium-holmium-doped tin oxide target, as prepared in this embodiment, onto a glass substrate using radio frequency sputtering deposition. The film was tested and found to have a resistivity of 2 mΩ·cm and a visible light transmittance of 94% at a wavelength of 650 nm.

[0024] Example 3: A method for preparing a gallium-holmium-doped tin oxide target according to the present invention includes the following steps: (1) Mix 0.1 kg gallium oxide powder, 0.03 kg holmium oxide powder, 9.87 kg tin oxide powder, 0.1 kg ammonium polyacrylate dispersant, 0.1 kg polyvinyl butyral binder and 4.8 kg water evenly to obtain a slurry; wherein the particle size of gallium oxide powder is 50 nm to 150 nm and the purity is 4N, the particle size of holmium oxide powder is 50 nm to 150 nm and the purity is 4N, and the particle size of tin oxide powder is 50 nm to 150 nm and the purity is 4N.

[0025] (2) The slurry obtained in step (1) is subjected to spray granulation, molding, and cold isostatic pressing in sequence to obtain the target blank; wherein the pressure of molding is 80MPa and the pressure is controlled at 300MPa during the cold isostatic pressing process.

[0026] (3) Under normal pressure, in a closed system without gas flow, the target blank obtained in step (2) is sintered at 1410°C for 6 hours to obtain a gallium-holmium-doped tin oxide target. In this embodiment, the relative density of the gallium-holmium-doped tin oxide target is 98.5%.

[0027] A transparent conductive film with a thickness of 700 nm to 800 nm was obtained by depositing gallium-holmium-doped tin oxide target, as prepared in this embodiment, onto a glass substrate using radio frequency sputtering deposition. The resistivity of the transparent conductive film was measured to be 1.3 mΩ·cm, and its visible light transmittance at a wavelength of 750 nm was 89%.

[0028] Example 4: A method for preparing a gallium-holmium-doped tin oxide target according to the present invention includes the following steps: (1) Mix 0.07 kg gallium oxide powder, 0.03 kg holmium oxide powder, 9.9 kg tin oxide powder, 0.12 kg ammonium polyacrylate dispersant, 0.12 kg polyvinyl butyral binder and 4.76 kg water evenly to obtain a slurry; wherein the particle size of gallium oxide powder is 50 nm to 150 nm and the purity is 4N, the particle size of holmium oxide powder is 50 nm to 150 nm and the purity is 4N, and the particle size of tin oxide powder is 50 nm to 150 nm and the purity is 4N.

[0029] (2) The slurry obtained in step (1) is subjected to spray granulation, molding and cold isostatic pressing in sequence to obtain the target blank; wherein the pressure of molding is 80MPa and the pressure is controlled at 350MPa during the cold isostatic pressing process.

[0030] (3) Under normal pressure, in a closed system without gas flow, the target blank obtained in step (2) is sintered at 1350°C for 7 hours to obtain a gallium-holmium-doped tin oxide target. In this embodiment, the relative density of the gallium-holmium-doped tin oxide target is 98.5%.

[0031] A transparent conductive film with a thickness of 800 nm to 900 nm was obtained by depositing gallium-holmium-doped tin oxide target, as prepared in this embodiment, onto a glass substrate using radio frequency sputtering deposition. The resistivity of the transparent conductive film was measured to be 1.5 mΩ·cm, and its visible light transmittance at a wavelength of 750 nm was 91%.

[0032] Comparative Example 1: A method for preparing gallium-doped tin oxide target includes the following steps: (1) Mix 0.2 kg gallium oxide powder, 9.8 kg tin oxide powder, 0.2 kg ammonium polyacrylate dispersant, 0.2 kg polyvinyl butyral binder and 4.6 kg water evenly to obtain a slurry; wherein the particle size of gallium oxide powder is 50 nm to 150 nm and the purity is 4N, and the particle size of tin oxide powder is 50 nm to 150 nm and the purity is 4N.

[0033] (2) The slurry obtained in step (1) is subjected to spray granulation, molding and cold isostatic pressing in sequence to obtain the target blank; wherein the pressure of molding is 80MPa and the pressure is controlled at 200MPa during the cold isostatic pressing process.

[0034] (3) Under normal pressure, in a closed system without gas flow, the target blank obtained in step (2) is sintered at 1450°C for 5 hours to obtain gallium-doped tin oxide target. In this embodiment, the relative density of the gallium-doped tin oxide target is 93.7%.

[0035] A transparent conductive film with a thickness of 800 nm to 900 nm was obtained by depositing gallium-doped tin oxide target material prepared in this comparative example on a glass substrate using radio frequency sputtering deposition. The resistivity of the transparent conductive film was measured to be 63.7 mΩ•cm, and the visible light transmittance at a wavelength of 650 nm was 89%.

[0036] Comparative Example 2: A method for preparing gallium-holmium-doped tin oxide target includes the following steps: (1) Mix 0.02 kg gallium oxide powder, 0.2 kg holmium oxide powder, 9.78 kg tin oxide powder, 0.05 kg ammonium polyacrylate dispersant, 0.05 kg polyvinyl butyral binder and 4.9 kg water evenly to obtain a slurry; wherein the particle size of gallium oxide powder is 50 nm to 150 nm and the purity is 4N, the particle size of holmium oxide powder is 50 nm to 150 nm and the purity is 4N, and the particle size of tin oxide powder is 50 nm to 150 nm and the purity is 4N.

[0037] (2) The slurry obtained in step (1) is subjected to spray granulation, molding and cold isostatic pressing in sequence to obtain the target blank; wherein the pressure of molding is 80MPa and the pressure is controlled at 400MPa during the cold isostatic pressing process.

[0038] (3) Under normal pressure, in a closed system without gas flow, the target blank obtained in step (2) is sintered at 1400°C for 7 hours to obtain a gallium-holmium-doped tin oxide target. In this embodiment, the relative density of the gallium-holmium-doped tin oxide target is 98.5%.

[0039] A transparent conductive film with a thickness of 500 nm to 600 nm was obtained by depositing gallium-holmium-doped tin oxide target, prepared in this comparative example, onto a glass substrate using radio frequency sputtering deposition. The resistivity of the transparent conductive film was measured to be 37.4 mΩ•cm, and its visible light transmittance at a wavelength of 650 nm was 82%.

[0040] Comparative Example 3: A method for preparing gallium-holmium-doped tin oxide target includes the following steps: (1) Mix 0.3 kg gallium oxide powder, 0.03 kg holmium oxide powder, 9.67 kg tin oxide powder, 0.1 kg ammonium polyacrylate dispersant, 0.1 kg polyvinyl butyral binder and 4.8 kg water evenly to obtain a slurry; wherein the particle size of gallium oxide powder is 50 nm to 150 nm and the purity is 4N, the particle size of holmium oxide powder is 50 nm to 150 nm and the purity is 4N, and the particle size of tin oxide powder is 50 nm to 150 nm and the purity is 4N.

[0041] (2) The slurry obtained in step (1) is subjected to spray granulation, molding, and cold isostatic pressing in sequence to obtain the target blank; wherein the pressure of molding is 80MPa and the pressure is controlled at 300MPa during the cold isostatic pressing process.

[0042] (3) Under normal pressure and in a gas-free atmosphere, the target blank obtained in step (2) is sintered at 1410°C for 6 hours to obtain a gallium-holmium-doped tin oxide target. In this embodiment, the relative density of the gallium-holmium-doped tin oxide target is 98.8%.

[0043] A transparent conductive film with a thickness of 700 nm to 800 nm was obtained by depositing gallium-holmium-doped tin oxide target, prepared in this comparative example, onto a glass substrate using radio frequency sputtering deposition. The resistivity of the transparent conductive film was measured to be 140.6 mΩ•cm, and its visible light transmittance at a wavelength of 750 nm was 85%.

[0044] Comparative Example 4: A method for preparing gallium-cerium-doped tin oxide target includes the following steps: (1) Mix 0.07 kg gallium oxide powder, 0.03 kg cerium oxide powder, 9.9 kg tin oxide powder, 0.12 kg ammonium polyacrylate dispersant, 0.12 kg polyvinyl butyral binder and 4.76 kg water evenly to obtain a slurry; wherein the particle size of gallium oxide powder is 50 nm to 150 nm and the purity is 4N, the particle size of cerium oxide powder is 50 nm to 150 nm and the purity is 4N, and the particle size of tin oxide powder is 50 nm to 150 nm and the purity is 4N.

[0045] (2) The slurry obtained in step (1) is subjected to spray granulation, molding and cold isostatic pressing in sequence to obtain the target blank; wherein the pressure of molding is 80MPa and the pressure is controlled at 350MPa during the cold isostatic pressing process.

[0046] (3) Under normal pressure and in a gas-free atmosphere, the target blank obtained in step (2) is sintered at 1350°C for 7 hours to obtain gallium-cerium-doped tin oxide target. In this embodiment, the relative density of the gallium-cerium-doped tin oxide target is 95.1%.

[0047] A transparent conductive film with a thickness of 800 nm to 900 nm was obtained by depositing gallium-holmium-doped tin oxide target, prepared in this comparative example, onto a glass substrate using radio frequency sputtering deposition. The resistivity of the transparent conductive film was measured to be 7.9 mΩ•cm, and its visible light transmittance at a wavelength of 750 nm was 80%.

[0048] Comparing the performance data of the doped tin oxide targets prepared in Examples 1-4 and Comparative Examples 1-4, it can be seen that compared with Example 1, the doped tin oxide target prepared in Comparative Example 1 without adding holmium oxide has a lower relative density, higher resistivity, and lower visible light transmittance at 750 nm wavelength. This indicates that holmium oxide doping can improve the density, conductivity, and transmittance of gallium-doped tin oxide targets. Compared with Example 2, Comparative Example 2 added more holmium oxide, resulting in a doped tin oxide target with higher resistivity and lower visible light transmittance at 750 nm wavelength. The decreased visible light transmittance indicates that excessive gallium oxide doping is detrimental to the conductivity and transmittance of the tin oxide target. Compared to Example 3, Comparative Example 3 added more gallium oxide, resulting in a higher resistivity and lower visible light transmittance at 750 nm for the prepared tin oxide target, indicating that excessive gallium oxide doping is detrimental to the conductivity and transmittance of the tin oxide target. Compared to Example 4, Comparative Example 4 added other rare earth oxides to replace holmium oxide, resulting in a lower density of the prepared tin oxide target, with higher resistivity and lower visible light transmittance. In summary, the gallium-holmium doped tin oxide targets prepared in Examples 1-4 have lower resistivity and higher visible light transmittance, and the resistivity of the transparent conductive films prepared from them is all below 2 mΩ·cm, while the visible light transmittance is all above 87%.

[0049] As can be seen from the above results, the method for preparing gallium-holmium-doped tin oxide target of the present invention uses gallium oxide, holmium oxide and tin oxide as raw materials. By optimizing gallium oxide (0.2% to 2%), holmium oxide (0.1% to 1%) and tin oxide (97% to 99.7%), and adding dispersant and binder, the method can produce gallium-holmium-doped tin oxide target with low resistivity and high visible light transmittance through granulation, molding, cold isostatic pressing and sintering.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall still fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for preparing a gallium-holmium-doped tin oxide target, characterized in that, Includes the following steps: (1) Gallium oxide, holmium oxide and tin oxide are mixed to obtain a mixed powder; the mixed powder contains 0.2% to 2% gallium oxide, 0.1% to 1% holmium oxide and 97% to 99.7% tin oxide by mass percentage; (2) Mix the mixed powder, dispersant, binder and water obtained in step (1) to obtain a slurry; (3) The slurry obtained in step (2) is granulated, molded, and cold isostatically pressed in sequence to obtain the target blank; (4) The target blank obtained in step (3) is sintered to obtain a gallium-holmium doped tin oxide target; the sintering temperature is 1200℃~1450℃; the sintering is carried out under sealed conditions.

2. The method for preparing gallium-holmium-doped tin oxide target according to claim 1, characterized in that, In step (3), the molding pressure is 60MPa to 100MPa.

3. The method for preparing gallium-holmium-doped tin oxide target according to claim 2, characterized in that, In step (3), the pressure of the cold isostatic pressing is 200MPa to 400MPa.

4. The method for preparing gallium-holmium-doped tin oxide target according to claim 3, characterized in that, In step (4), the sintering time is 5h to 9h.

5. The method for preparing a gallium-holmium-doped tin oxide target according to any one of claims 1 to 4, characterized in that, In step (1), the gallium oxide has a particle size of 50nm to 150nm and a purity of 4N; the holmium oxide has a particle size of 50nm to 150nm and a purity of 4N; the tin oxide has a particle size of 50nm to 150nm and a purity of 4N.

6. The method for preparing a gallium-holmium-doped tin oxide target according to any one of claims 1 to 4, characterized in that, In step (2), the amount of dispersant added is 0.2% to 5% of the total mass of the mixed powder; the amount of binder added is 0.2% to 5% of the total mass of the mixed powder; and the solid content of the slurry is 50% to 70%.

7. The method for preparing gallium-holmium-doped tin oxide target according to claim 6, characterized in that, The dispersant is ammonium polyacrylate, and the binder is polyvinyl butyral.

8. The method for preparing a gallium-holmium-doped tin oxide target according to any one of claims 1 to 4, characterized in that, In step (3), the granulation is spray granulation.

9. A gallium-holmium doped tin oxide target, characterized in that, It is prepared by any one of the preparation methods described in claims 1 to 8.