IZO ceramic target and method for manufacturing the same

Abstract

The application discloses an IZO ceramic target material and a preparation method thereof. 4+ and Ce 4+ account for 10-20 wt% of the metal-organic complex; indium oxide, zinc oxide and modified rare earth powder are mixed according to an atomic ratio of In:Zn:Pr:Ce (80-95):(5-15):(0.1-2.5):(0.1-2.5), graphene nanosheets are added, and the high-performance target material is prepared through ball milling, ultrasonic dispersion, hot-pressing sintering and annealing control of oxygen partial pressure.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of ceramic targets, in particular to an IZO ceramic target and a preparation method thereof. BACKGROUND

[0002] With the rapid evolution of semiconductor material science and thin film deposition technology, nano-ceramic targets, as the core components of sputtering coating processes, have gradually evolved from traditional oxide ceramic systems to high-performance, multifunctional nanostructures. As early as the late 20th century, indium tin oxide (ITO) targets dominated the field of transparent conductive thin films. Subsequently, with the explosive growth of display devices and photovoltaic industries, indium zinc oxide (IZO) targets emerged. Based on the In2O3-ZnO composite system, amorphous or nanocrystalline thin films are prepared by methods such as magnetron sputtering or pulsed laser deposition, significantly improving the carrier mobility and optical transmittance. In the early 21st century, the focus of research and development of nano-ceramic targets shifted to doping optimization and microstructure regulation, for example, the introduction of rare earth or transition metal elements to improve electrical properties. Meanwhile, benefiting from the progress of powder metallurgy and hot-pressing sintering processes, the density and uniformity of the targets have been greatly improved, promoting their application in flexible electronics, thin film transistors (TFTs), and solar cell buffer layers. In recent years, with the deep integration of nanotechnology and quantum effects, the particle size control of IZO-based targets has reached the sub-nanometer level. Combined with advanced methods such as vacuum evaporation and ion beam assisted deposition, the potential of IZO-based targets in high-resolution OLED displays and perovskite photovoltaic devices has been further expanded. The global market continues to expand, and domestic manufacturers are gradually breaking international monopolies through independent innovation, achieving a leap from basic research to industrialization. These advances not only result from the refinement of material synthesis processes but also benefit from a deep understanding of defect engineering and phase transition mechanisms, enabling nano-ceramic targets to transition from single-functionality to intelligent and controllable directions. Despite the remarkable achievements in nano-ceramic target technology, existing systems still face the bottleneck problem of adjustable resistivity range. In traditional IZO targets, resistivity adjustment mainly relies on oxygen vacancies or intrinsic doping mechanisms, but this method often leads to difficulty in accurately controlling carrier concentration, failing to meet the low resistivity requirements of high-precision electronic devices. In addition, the shortcomings of existing technologies in multi-valence ion conversion make the resistivity adjustment process susceptible to environmental factors such as oxygen partial pressure or heat treatment temperature, resulting in poor repeatability and stability of thin film electrical properties. These defects manifest in actual applications as low overall energy efficiency and large fluctuations in mobility. SUMMARY

[0003] The application provides a preparation method of an IZO ceramic target material, and the preparation method comprises the following steps: step S1, chemically modifying praseodymium oxide and cerium oxide powders, forming a metal-organic complex through coordination of a chelating agent with praseodymium ions and cerium ions, and obtaining modified rare earth powders through centrifugal separation and vacuum drying, wherein Pr 4+ and Ce 4+ each account for 10 wt% to 20 wt% of total praseodymium ions and total cerium ions; step S2, mixing indium oxide, zinc oxide and the modified rare earth powders according to a preset ratio to form a precursor mixture, wherein the preset ratio is an atomic ratio of In:Zn:Pr:Ce of (80-95):(5-15):(0.1-2.5):(0.1-2.5), the purity of the indium oxide, zinc oxide, praseodymium oxide and cerium oxide powders is greater than or equal to 99.99%, and the initial particle size is 50 nm to 200 nm; step S3, uniformly nanoizing the precursor mixture through ball milling and ultrasonic dispersion; and step S4, performing hot-pressing sintering on the precursor mixture under an inert atmosphere, controlling the temperature at 800 DEG C to 1200 DEG C, controlling the pressure at 20 MPa to 50 MPa, and performing subsequent annealing treatment to regulate oxygen partial pressure, so as to obtain the IZO ceramic target material.

[0004] It should be noted that in step S1, the praseodymium oxide and cerium oxide powders are chemically modified, a chelating agent is used to form a metal-organic complex with praseodymium ions and cerium ions, and stepwise coordination and pulse microwave radiation are used to assist, so as to accurately control Pr 4+ and Ce 4+ each account for 10 wt% to 20 wt% of total praseodymium ions and total cerium ions, Pr 4+ introduce more oxygen vacancies through a higher oxidation state, enhance the carrier concentration, and Ce 4+ due to a stable tetravalent state and a strong oxygen affinity, can locally inhibit an excessively high oxygen vacancy concentration, prevent fluctuations in electrical properties, and balance the carrier concentration and the mobility; in step S2, the atomic ratio of In:Zn:Pr:Ce is accurately set to 80-95:5-15:0.1-2.5:0.1-2.5, high-purity (greater than or equal to 99.99%) and 50-200 nm particle size raw materials are combined, and the uniformity of the chemical composition is ensured. In step S3, sub-nanometer uniformization is realized through ball milling and ultrasonic dispersion, and the particle contact and the grain boundary structure are optimized. In step S4, hot-pressing sintering (800-1200 DEG C, 20-50 MPa) and annealing are used to regulate the oxygen partial pressure, so as to promote densification and optimize the oxygen vacancy distribution.

[0005] As a preferred technical solution of the preparation method of the IZO ceramic target material, the chemical modification step comprises: stepwise adding praseodymium oxide and cerium oxide powders in a mass ratio of 1:1 to 2:1 in a chelating agent solution containing 0.05 mol / L to 0.2 mol / L triethanolamine, first reacting at 40°C to 60°C for 1 hour to 2 hours to form a praseodymium-organic complex, and then increasing the temperature to 60°C to 80°C for 1 hour to 2 hours to introduce cerium ions to form a double rare earth complex; and adding 0.1 wt% to 0.5 wt% of polyethylene glycol surfactant, and using low-frequency ultrasonic waves with a frequency of 15 kHz to 25 kHz and a power of 100 W to 300 W.

[0006] It should be noted that TEA, as a non-acid chelating agent, relies on its hydroxyl and amine groups to form a multidentate coordination complex with rare earth ions through the lone pair of electrons of oxygen and nitrogen atoms. At 40°C to 60°C, Pr 3+ / Pr 4+ ) ions form a stable praseodymium-organic complex. The mild temperature ensures that the proportion of Pr 4+ is controlled at 10 wt% to 20 wt%, avoiding rapid oxidation; then the temperature is increased to 60°C to 80°C, and cerium oxide powder is introduced in a mass ratio of 1:1 to 2:1, and reacted for 1 hour to 2 hours to form a double rare earth complex. The higher temperature promotes the coordination of Ce 3+ / Ce 4+ ) ions with TEA, and the proportion of Ce 4+ is 10 wt% to 20 wt%, and the multivalent state synergy of praseodymium and cerium optimizes the oxygen vacancy and carrier concentration. The addition of 0.1 wt% to 0.5 wt% of polyethylene glycol (PEG) as a surfactant reduces the surface energy of the particles through steric hindrance effect, prevents agglomeration, and improves the dispersibility of the powder. Low-frequency ultrasonic waves (15 kHz to 25 kHz, 100 W to 300 W) generate a local high-temperature and high-pressure microenvironment through acoustic cavitation effect, enhancing the uniformity of molecular diffusion and coordination reaction.

[0007] As a preferred technical solution of the preparation method of the IZO ceramic target material, the chemical modification step comprises: stepwise adding praseodymium oxide and cerium oxide powders in a mass ratio of 1:1 to 2:1 in a chelating agent solution containing 0.05 mol / L to 0.2 mol / L triethanolamine, first reacting at 40°C to 60°C for 1 hour to 2 hours to form a praseodymium-organic complex, and then increasing the temperature to 60°C to 80°C for 1 hour to 2 hours to introduce cerium ions to form a double rare earth complex; and adding 0.1 wt% to 0.5 wt% of polyethylene glycol surfactant, and using low-frequency ultrasonic waves with a frequency of 15 kHz to 25 kHz and a power of 100 W to 300 W.

[0008] It should be noted that in a weakly acidic environment with a pH of 4.0 to 5.0, the amine group and the hydroxyl group of TEA preferentially form a stable praseodymium-organic complex with Pr 3+ / Pr 4+ ) ions, and this pH range is conducive to the formation of Pr 4+generation (10 wt% to 20 wt%), inhibits excessive oxidation reaction by moderate acidity, reduces byproduct generation, while ensuring the stability of the complex. Subsequently, by slowly adding a basic reagent (such as sodium hydroxide or ammonia water), the pH is adjusted to 5.5 to 6.5, optimizing the coordination environment of cerium ions (Ce 3+ / Ce 4+ ), promoting the formation of a double rare earth complex of TEA and cerium ions, this pH range enhances the stability of Ce 4+ (10 wt% to 20 wt%), and cooperatively regulates the oxygen vacancy distribution of praseodymium ions through the strong oxygen affinity of cerium. Dynamic pH regulation ensures the stepwise coordination of praseodymium and cerium ions, avoiding uneven valence caused by competitive coordination, combined with the dispersion effect of polyethylene glycol (PEG) and the molecular diffusion enhancement effect of low-frequency ultrasound (15-25 kHz, 100-300 W), further improving the uniformity and powder dispersity of the complex, providing high-quality precursors for subsequent sintering, significantly optimizing the electrical performance of IZO targets, and meeting the needs of high-precision thin film devices.

[0009] As a preferred technical solution of the preparation method of the IZO ceramic target, the rotation speed of the centrifugal separation is 5000 rpm to 8000 rpm, and the time is 10 minutes to 15 minutes; the temperature of the vacuum drying is 60°C to 80°C, the vacuum degree is 0.01 Pa, and the time is 6 hours to 12 hours.

[0010] It should be noted that by efficiently removing solvents and impurities, the high purity of the modified rare earth powder is ensured, providing high-quality precursors for subsequent IZO target preparation.

[0011] As a preferred technical solution of the preparation method of the IZO ceramic target, the ball milling step uses zirconia balls as the grinding medium, the ball-to-material ratio is 10:1 to 20:1, the ball milling time is 4 hours to 8 hours, and ultrasonic dispersion is combined, the frequency is 20 kHz to 40 kHz, the power is 200 W to 400 W, and the time is 1 hour to 2 hours.

[0012] It should be noted that the precursor mixture is refined to the sub-nanometer level through mechanical grinding and acoustic cavitation effect, enhancing the uniformity and contact area of the particles, and providing a high-density basis for hot-press sintering.

[0013] As a preferred technical solution of the preparation method of the IZO ceramic target, a segmented temperature rising strategy is adopted during the hot-press sintering process, the initial temperature is 600°C to 800°C, maintained for 1 hour to 2 hours, the middle temperature is 900°C to 1100°C, maintained for 2 hours to 4 hours, and the final temperature is 1100°C to 1200°C, maintained for 1 hour to 3 hours.

[0014] It should be noted that the particle diffusion, grain growth and defect control are promoted by gradually increasing the temperature and holding time, and the density and microstructure stability of the IZO target material are optimized.

[0015] As a preferred technical solution of the preparation method of the IZO ceramic target material, the annealing treatment is carried out in a nitrogen or argon atmosphere, the oxygen partial pressure is controlled to be 0.001 Pa to 0.1 Pa, the annealing temperature is 600°C to 900°C, and the time is 2 hours to 6 hours.

[0016] It should be noted that the electrical properties and structural stability of the IZO target material are optimized by precisely controlling the oxygen vacancy concentration, and the high-precision thin film device requirements are met.

[0017] As a preferred technical solution of the preparation method of the IZO ceramic target material, 0.01 wt% to 0.1 wt% of graphene nanosheet is added as an auxiliary dopant in the precursor mixture.

[0018] It should be noted that the graphene nanosheet has a high specific surface area and excellent electron transfer capacity, is uniformly dispersed in the mixture, interacts with the electronic structure of rare earth ions through its π electron system, enhances the carrier mobility, and its reducing property helps to control the oxygen vacancy concentration, balances the carrier concentration and electrical stability. In the ball milling and ultrasonic dispersion process, the graphene nanosheet further promotes the uniform distribution of the particles and reduces the grain boundary defects. In the subsequent hot-pressing sintering and annealing, the graphene maintains the integrity of the microstructure through thermal stability and chemical inertness, prevents abnormal grain growth caused by excessively high temperature, and thus improves the density and electrical uniformity of the target material, meeting the requirements of high-precision thin film devices (such as OLED and TFT) for high mobility and stability.

[0019] In addition, the IZO ceramic target material prepared by the above preparation method is provided.

[0020] The IZO ceramic target material preparation method of the application significantly improves the target material performance through double rare earth (Pr and Ce) doping, chemical modification and graphene assistance, and has the following beneficial effects: the density reaches 7.00-7.08 g / cm 3 (98.6%-99.7%), close to the theoretical value, ensuring the mechanical strength and sputtering stability; the resistivity is as low as 2.0-2.5×10 -4 Ω·cm, the carrier concentration is 1.8-2.2×10 20 cm -3 , the mobility reaches 35-40 cm 2 / V·s, the electrical performance is excellent, and meets the requirements of high-precision thin film devices (such as OLED and TFT) for high mobility and low resistivity. 4+ Pr 4+The synergistic effect optimizes the oxygen vacancy distribution, enhances the balance of carrier concentration and mobility, and improves the uniformity of the powder by chemical modification combined with TEA and PEG. Graphene promotes electron transfer and microstructure stability, significantly improves the target density, electrical properties, and sputtering film quality, breaks the resistance regulation bottleneck of traditional IZO targets, and provides high-performance material support for the flexible electronics and photovoltaic industries. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 Spectrum analysis chart of Pr / Ce-complex + PEG in Example 1 of the present application. DETAILED DESCRIPTION

[0022] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the embodiments of the specification.

[0023] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present application, therefore the present application is not limited to the specific embodiments disclosed below.

[0024] Secondly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an embodiment that is separate or selectively excluded from other embodiments.

[0025] EMBODIMENT

[0026] EMBODIMENT 1

[0027] Step S1: Chemical modification of praseodymium oxide and cerium oxide powder. First, prepare a 0.05 mol / L triethanolamine chelating agent solution, and add praseodymium oxide and cerium oxide powder to the solution in a mass ratio of 1:1. Specifically, first add praseodymium oxide powder, react at 40℃ for 1 hour, and keep the solution pH value at 4.0 (controlled by adding 0.2 mol / L dilute hydrochloric acid) to form a praseodymium-organic complex; then increase the temperature to 60℃, add cerium oxide powder, continue to react for 1 hour, and adjust the solution pH value to 5.5 (controlled by adding 0.2 mol / L sodium hydroxide) to introduce cerium ions to form a double rare earth complex. In this process, 0.3 wt% of polyethylene glycol is added as a surfactant, and low-frequency ultrasonic waves are used to assist (frequency 15 kHz, power 100 W) to enhance molecular diffusion and the uniformity of the complexation reaction. Through this modification, Pr 4+ 10 wt% of total praseodymium ions, Ce4+ wt% of total cerium ions. Subsequently, centrifugal separation was performed at a speed of 5000 rpm for 10 minutes, followed by vacuum drying at a temperature of 60°C, a vacuum degree of 0.01 Pa for 6 hours to obtain the modified rare earth powder.

[0028] Step S2: Indium oxide, zinc oxide and the above modified rare earth powder with a purity of 99.99% and an initial particle size of 50 nm were mixed in a ratio of In:Zn:Pr:Ce atomic ratio of 80:15:0.1:0.1 to form a precursor mixture. At the same time, 0.01 wt% of graphene nanosheet was added as an auxiliary dopant in the mixture to ensure uniform distribution by high-speed stirring (500 rpm, 30 minutes).

[0029] Step S3: The precursor mixture was uniformly nano-sized by ball milling and ultrasonic dispersion. Specifically, zirconium oxide balls were used as grinding media, the ball-to-material ratio was 10:1, and the ball milling time was 4 hours; then combined with ultrasonic dispersion, the frequency was 20 kHz, the power was 200 W, and the time was 1 hour, to achieve sub-nanometer distribution of powder particle size.

[0030] Step S4: The precursor mixture was subjected to hot-pressing sintering under a nitrogen inert atmosphere, with a pressure of 20 MPa. A staged temperature rising strategy was adopted: the initial temperature was 600°C for 1 hour, the middle temperature was 900°C for 2 hours, and the final temperature was 1100°C for 1 hour. Subsequently, annealing treatment was performed under a nitrogen atmosphere, with an oxygen partial pressure of 0.001 Pa, an annealing temperature of 600°C, and a time of 2 hours, to control the oxygen partial pressure and obtain the IZO ceramic target material.

[0031] Example 2

[0032] Step S1: The praseodymium oxide and cerium oxide powders were chemically modified. First, a 0.1 mol / L triethanolamine chelating agent solution was prepared, and the praseodymium oxide and cerium oxide powders were added to the solution in a mass ratio of 1.5:1. Specifically, the praseodymium oxide powder was first added, and the reaction was carried out at 50°C for 1.5 hours, while the pH value of the solution was maintained at 4.5 (controlled by adding 0.3 mol / L dilute hydrochloric acid), to form a praseodymium-organic complex; then the temperature was raised to 70°C, the cerium oxide powder was added, and the reaction was continued for 1.5 hours, while the pH value of the solution was adjusted to 6.0 (controlled by adding 0.3 mol / L sodium hydroxide), to introduce cerium ions and form a double rare earth complex. In this process, 0.1 wt% of polyethylene glycol was added as a surfactant, and low-frequency ultrasonic waves were used to assist (frequency 20 kHz, power 200 W) to enhance the uniformity of molecular diffusion and complexation reaction. Through this modification, Pr 4+ wt% of total praseodymium ions, and Ce4+ wt% of total cerium ions. Subsequently, centrifugal separation was performed at 6000 rpm for 12 minutes, followed by vacuum drying at 70°C for 8 hours under a vacuum of 0.01 Pa to obtain the modified rare earth powder.

[0033] Step S2: Indium oxide, zinc oxide and the above modified rare earth powder with a purity of 99.99% and an initial particle size of 100 nm were mixed in a ratio of In:Zn:Pr:Ce atomic ratio of 85:10:1:1 to form a precursor mixture. At the same time, 0.05 wt% of graphene nanosheets were added as an auxiliary dopant in the mixture to ensure uniform distribution by high-speed stirring (400 rpm, 40 minutes).

[0034] Step S3: The precursor mixture was uniformly nano-sized by ball milling and ultrasonic dispersion. Specifically, zirconium oxide balls were used as the grinding medium, the ball-to-material ratio was 15:1, and the ball milling time was 6 hours; then ultrasonic dispersion was combined, the frequency was 30 kHz, the power was 300 W, and the time was 1.5 hours, to achieve a sub-nanometer distribution of the powder particle size.

[0035] Step S4: The precursor mixture was subjected to hot-press sintering under an argon inert atmosphere, with a pressure of 30 MPa. A staged temperature rising strategy was adopted: the initial temperature was 700°C for 1.5 hours, the intermediate temperature was 1000°C for 3 hours, and the final temperature was 1150°C for 2 hours. Subsequently, annealing treatment was performed under an argon atmosphere, with an oxygen partial pressure of 0.01 Pa, an annealing temperature of 750°C, and a time of 4 hours, to control the oxygen partial pressure and obtain the IZO ceramic target material.

[0036] Example 3

[0037] Step S1: The praseodymium oxide and cerium oxide powders were chemically modified. First, a 0.2 mol / L triethanolamine chelating agent solution was prepared, and the praseodymium oxide and cerium oxide powders were added to the solution in a mass ratio of 2:1. Specifically, the praseodymium oxide powder was first added, and the solution was reacted at 60°C for 2 hours while maintaining the solution pH at 5.0 (controlled by adding 0.1 mol / L dilute hydrochloric acid), to form a praseodymium-organic complex; then the temperature was raised to 80°C, the cerium oxide powder was added, and the reaction was continued for 2 hours while adjusting the solution pH to 6.5 (controlled by adding 0.1 mol / L sodium hydroxide), to introduce cerium ions and form a double rare earth complex. In this process, 0.2 wt% of polyethylene glycol was added as a surfactant, and low-frequency ultrasonic waves were used to assist (frequency 25 kHz, power 300 W) to enhance molecular diffusion and complex reaction uniformity. Through this modification, Pr 4+ wt% of total praseodymium ions, and Ce 4+10 wt% of total cerium ions. Subsequently, centrifugal separation was performed at 8000 rpm for 15 minutes, followed by vacuum drying at 80℃ for 12 hours under a vacuum of 0.01 Pa to obtain the modified rare earth powder.

[0038] Step S2: Indium oxide, zinc oxide and the above modified rare earth powder with a purity of 99.99% and an initial particle size of 200 nm were mixed in a ratio of In:Zn:Pr:Ce atomic ratio of 95:5:2.5:0.5 to form a precursor mixture. At the same time, 0.1 wt% of graphene nanosheet was added as an auxiliary dopant in the mixture to ensure uniform distribution by high-speed stirring (600 rpm, 20 minutes).

[0039] Step S3: The precursor mixture was uniformly nano-sized by ball milling and ultrasonic dispersion. Specifically, zirconium oxide balls were used as the grinding medium, the ball-to-material ratio was 20:1, and the ball milling time was 8 hours; then ultrasonic dispersion was combined, the frequency was 40 kHz, the power was 400 W, and the time was 2 hours to achieve sub-nanometer distribution of the powder particle size.

[0040] Step S4: The precursor mixture was subjected to hot-press sintering under a nitrogen inert atmosphere at a pressure of 50 MPa. A staged temperature rising strategy was adopted: the initial temperature was 800℃ for 2 hours, the middle temperature was 1100℃ for 4 hours, and the final temperature was 1200℃ for 3 hours. Subsequently, annealing treatment was performed under a nitrogen atmosphere with an oxygen partial pressure of 0.1 Pa at an annealing temperature of 900℃ for 6 hours to control the oxygen partial pressure to obtain the IZO ceramic target material.

[0041] Example 4

[0042] Step S1: The praseodymium oxide and cerium oxide powders were chemically modified. First, a 0.15 mol / L triethanolamine chelating agent solution was prepared, and the praseodymium oxide and cerium oxide powders were added to the solution in a mass ratio of 1:1.5. Specifically, the praseodymium oxide powder was first added, and the reaction was carried out at 45℃ for 1.2 hours while maintaining the solution pH at 4.2 (controlled by adding 0.4 mol / L dilute hydrochloric acid), forming a praseodymium-organic complex; then the temperature was raised to 65℃, the cerium oxide powder was added, and the reaction was continued for 1.2 hours while adjusting the solution pH to 5.8 (controlled by adding 0.4 mol / L sodium hydroxide), introducing cerium ions to form a double rare earth complex. In this process, 0.5 wt% of polyethylene glycol was added as a surfactant, and low-frequency ultrasonic waves were used to assist (frequency 18 kHz, power 150 W) to enhance molecular diffusion and complex reaction uniformity. Through this modification, Pr 4+ 20 wt% of total praseodymium ions, Ce 4+The proportion of cerium ions in the total cerium ions is 12 wt%. Subsequently, centrifugal separation is performed at a speed of 7000 rpm for 13 minutes, followed by vacuum drying at a temperature of 65°C, a vacuum degree of 0.01 Pa, and a time of 10 hours to obtain the modified rare earth powder.

[0043] Step S2: In oxide, Zn oxide and the above modified rare earth powder with a purity of 99.99% and an initial particle size of 150 nm are mixed in a ratio of In:Zn:Pr:Ce atomic ratio of 90:8:0.5:2 to form a precursor mixture. At the same time, 0.08 wt% of graphene nanosheet is added as an auxiliary dopant in the mixture to ensure uniform distribution by high-speed stirring (300 rpm, 50 minutes).

[0044] Step S3: The precursor mixture is uniformly nano-sized by ball milling and ultrasonic dispersion. Specifically, zirconia balls are used as the grinding medium, the ball-to-material ratio is 12:1, and the ball milling time is 5 hours; then ultrasonic dispersion is combined, the frequency is 25 kHz, the power is 250 W, and the time is 1 hour, to achieve sub-nanometer distribution of the powder particle size.

[0045] Step S4: The precursor mixture is subjected to hot-pressing sintering under an argon inert atmosphere, with a pressure of 40 MPa. A staged temperature rising strategy is adopted: the initial temperature is 650°C for 1 hour, the middle temperature is 950°C for 2.5 hours, and the final temperature is 1120°C for 1.5 hours. Subsequently, annealing treatment is performed under an argon atmosphere, with an oxygen partial pressure of 0.05 Pa, an annealing temperature of 800°C, and a time of 3 hours, to control the oxygen partial pressure and obtain the IZO ceramic target material.

[0046] Comparative Example

[0047] Comparative Example 1

[0048] Comparative Example 1 and Example 1 are compared in step S1, only using praseodymium oxide for chemical modification, omitting cerium oxide, and keeping the total rare earth content consistent.

[0049] Comparative Example 2

[0050] Comparative Example 2 and Example 1 are compared in step S1, only using cerium oxide for chemical modification, omitting praseodymium oxide, and keeping the total rare earth content consistent.

[0051] Comparative Example 3

[0052] Comparative Example 3 and Example 1 are compared in step S1, omitting the chemical modification process of praseodymium oxide and cerium oxide powder (i.e. not using triethanolamine chelating agent, dynamic pH control, low-frequency ultrasonic wave and polyethylene glycol surfactant), directly using original praseodymium oxide and cerium oxide powder.

[0053] Comparative Example 4

[0054] This comparative example 3 is compared with example 1, omitting the addition of 0.01 wt% graphene nanoplatelets as an auxiliary dopant.

[0055] Performance Test Methods

[0056] 1. Density: The density of the target material is measured using the Archimedes method. A high-precision electronic balance (precision 0.0001 g) is used to measure the dry weight, wet weight, and suspended weight of the sample. The sample is placed in a deionized water constant temperature tank to ensure stable water temperature. The sample surface needs to be cleaned and dried to avoid bubble interference, and the test is repeated multiple times to take the average value.

[0057] 2. Resistivity: The resistivity of the target material is measured using the four-probe method. A four-probe tester (such as Keithley 2400 source meter) is used to apply a constant current to the sample surface and measure the voltage between the two probes. The test is carried out at room temperature (25°C), and the sample surface needs to be polished and cleaned to remove the oxide layer to ensure accurate results.

[0058] 3. Carrier concentration and mobility: The carrier concentration and mobility of the target material are evaluated by the Hall effect test. A Hall effect test system (such as Lakeshore 8400 series) is used to apply a current under a constant magnetic field of 0.5-1 T and measure the Hall voltage of the sample. The sample needs to be cut into a size of 10 mm × 10 mm × 1 mm, and the surface needs to be polished and cleaned to remove impurities. The test is carried out in a vacuum or inert atmosphere (such as nitrogen or argon) to avoid oxygen adsorption interference. The test is repeated multiple times to take the average value to ensure data reliability.

[0059] Table 1

[0060]

[0061] In combination with example 1 and Figure 1 It can be seen that the spectrum of Pr / Ce-complex + PEG in the figure (yellow curve) shows significant characteristic changes compared with the reference TEA (blue curve) and Pr-complex (orange curve): the O-H stretching vibration peak is red-shifted from about 3300 cm -1 to about 3260 cm -1 , the C-N stretching vibration peak is red-shifted from 1300 cm -1 to about 1260 cm -1 , and the C-O stretching vibration peak is red-shifted from 1100 cm -1 to about 1055 cm -1, indicating the formation of coordination bonds between the molecules and Pr and Ce, resulting in increased bond length and decreased vibrational frequency. In addition, new absorption peaks appeared in the Pr / Ce-complex + PEG spectra, such as the PEG C-O-C stretching vibration peak at about 1125 cm -1 and the PEG terminal O-H stretching vibration peak at 3410 cm-1, further supporting the complex formation of PEG with Pr / Ce-complexes. The differences in the intensity and width of the peaks also reflect the complex coordination environment and the enhancement of intermolecular interactions, thus confirming the successful synthesis of Pr / Ce-complexes.

[0062] As can be seen in combination with Examples 1 to 4 and Table 1, the performance data of the IZO ceramic target material range from a density of 7.00 - 7.08 g / cm 3 (98.6% - 99.7%), a resistivity of 2.0 - 2.5 x 10 -4 Ω·cm, a carrier concentration of 1.8 - 2.2 x 10 20 cm -3 , and a mobility of 35 - 40 cm 2 / V·s.

[0063] As can be seen in combination with Example 1, Comparative Example 1, Comparative Example 2 and Table 1, the performance data of the IZO ceramic target material range from a density of 7.00 g / cm 3 (98.6%), a resistivity of 2.5 x 10 -4 Ω·cm, a carrier concentration of 1.8 x 10 20 cm -3 , and a mobility of 35 cm 2 / V·s for Example 1; a density of 6.90 g / cm 3 (97.2%), a resistivity of 4.0 x 10 -4 Ω·cm, a carrier concentration of 1.2 x 10 20 cm -3 , and a mobility of 25 cm 2 / V·s for Comparative Example 1 (Pr-doped only); a density of 6.85 g / cm 3 (96.5%), a resistivity of 4.5 x 10 -4 Ω·cm, a carrier concentration of 1.0 x 10 20 cm -3 , and a mobility of 22 cm 2 / V·s for Comparative Example 2 (Ce-doped only). Example 1, which is doped with both Pr and Ce rare earths, in combination with chemical modification and graphene addition, is significantly superior to the single rare earth doped comparative examples. Pr 4+ introduces more oxygen vacancies through high oxidation states, increasing the carrier concentration, while Ce4+ The strong oxygen affinity stabilizes the oxygen vacancy distribution, prevents the electrical performance fluctuation, and the synergistic effect of the two optimizes the balance between the oxygen vacancy concentration and the carrier mobility, enhances the density and conductivity of the target material, significantly improves the electrical performance, and meets the demand of high-precision thin film devices.

[0064] As can be seen from Example 1, Comparative Example 3 and Table 1, the density of Example 1 is 7.00 g / cm 3 (98.6%), the resistivity is 2.5 x 10 -4 Ω·cm, the carrier concentration is 1.8 x 10 20 cm -3 , and the mobility is 35 cm 2 / V·s; the density of Comparative Example 3 (without chemical modification, directly using original praseodymium and cerium oxides) is 6.80 g / cm 3 (95.8%), the resistivity is 5.0 x 10 -4 Ω·cm, the carrier concentration is 0.8 x 10 20 cm -3 , and the mobility is 20 cm 2 / V·s. Example 1 is significantly superior to Comparative Example 3 in density, electrical performance (resistivity, carrier concentration, mobility), etc. Example 1 forms a metal-organic complex of Pr and Ce through chemical modification of triethanolamine (TEA), combines low-frequency ultrasonic waves and polyethylene glycol (PEG) dispersion, optimizes the uniformity and particle size of the powder, and enhances the density in the sintering process; Pr 4+ and Ce 4+ (such as 10-20 wt% each) synergistically regulate the oxygen vacancies, Pr 4+ increases the carrier concentration, Ce 4+ stabilizes the oxygen vacancy distribution, and enhances the electrical performance stability; graphene nanosheets (0.01 wt%) further promote electron transfer, reduce the resistivity, and improve the mobility. Comparative Example 3 lacks chemical modification, leading to particle agglomeration, uneven oxygen vacancy distribution, significant decrease in density and electrical performance, and inability to meet the demand of high-precision thin film devices.

[0065] As can be seen from Example 1, Comparative Example 4 and the data in Table 1, the performance of the IZO ceramic target material of Example 1 is superior to that of Comparative Example 4. The density of Example 1 is 7.00 g / cm 3 (98.6%), the resistivity is 2.5 x 10 -4 Ω·cm, the carrier concentration is 1.8 x 10 20 cm -3 , and the mobility is 35 cm 2 / V·s; while the density of Comparative Example 4 (omitting graphene nanosheets) is 6.95 g / cm 3(97.9%), resistivity of 3.5 x 10 -4 Ω-cm, carrier concentration of 1.5 x 10 20 cm -3 , mobility of 30 cm 2 / V-s. Example 1 significantly optimizes the target material performance by adding 0.01 wt% graphene nanosheets, combined with praseodymium (Pr 4+ ) and cerium (Ce 4+ ) double rare earth doping and triethanolamine chemical modification. The high specific surface area and π-electron system of graphene enhance electron transfer, promote uniform particle distribution, reduce grain boundary defects, thereby improving density and electrical conductivity; its reducing property helps to regulate oxygen vacancies, balance carrier concentration and mobility. Pr 4+ increases oxygen vacancies to improve carrier concentration, Ce 4+ stabilizes oxygen vacancy distribution, and synergistically improves electrical stability. Comparative Example 4 retains double rare earth doping and chemical modification, but lacks the dispersion and electron transfer effect of graphene, resulting in slightly inferior particle distribution, increased grain boundary defects, weakened oxygen vacancy regulation effect, and slightly lower density, electrical performance and mobility than Example 1, making it difficult to fully meet the needs of high-precision thin film devices.

[0066] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions described in the foregoing embodiments or make equivalent replacements to some technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing an IZO ceramic target material, characterized by, The preparation method comprises the following steps: Step S1. Chemically modifying praseodymium oxide and cerium oxide powders to form metal-organic complexes by coordination of chelating agents with praseodymium ions and cerium ions, and obtaining modified rare earth powders by centrifugal separation and vacuum drying, wherein Pr 4+ and Ce 4+ each account for 10 wt% to 20 wt% of total praseodymium ions and total cerium ions; Step S2. Ingot oxide, zinc oxide and the modified rare earth powder are mixed in a preset ratio to form a precursor mixture, wherein the preset ratio is In:Zn:Pr:Ce atomic ratio (80-95):(5-15):(0.1-2.5):(0.1-2.5), the purity of the ingot oxide, zinc oxide, praseodymium oxide and cerium oxide powder is ≥99.99%, and the initial particle size is 50 nm to 200 nm; Step S3. The precursor mixture is uniformly nano-sized by ball milling and ultrasonic dispersion; Step S4. The precursor mixture is subjected to hot-press sintering under an inert atmosphere, the temperature is controlled at 800-1200℃, the pressure is 20-50 MPa, and subsequent annealing treatment is performed to control the oxygen partial pressure, thereby obtaining the IZO ceramic target material; The chemical modification step comprises: stepwise adding praseodymium oxide and cerium oxide powder in a mass ratio of 1:1 to 2:1 in a chelating agent solution containing 0.05-0.2 mol / L triethanolamine, first reacting at 40-60℃ for 1-2 hours to form a praseodymium-organic complex, then increasing the temperature to 60-80℃ for 1-2 hours to introduce cerium ions to form a double rare earth complex; at the same time, 0.1-0.5 wt% polyethylene glycol surfactant is added, low-frequency ultrasonic waves are used, the frequency is 15-25 kHz, and the power is 100-300 W; wherein the pH value of the solution is dynamically controlled, first maintained at pH 4.0-5.0 to form the praseodymium-organic complex, and then adjusted to pH 5.5-6.5 to introduce the cerium ions.

2. The method of claim 1, wherein the IZO ceramic target is prepared by the steps of: The centrifugal separation speed is 5000-8000 rpm, and the time is 10-15 minutes; the vacuum drying temperature is 60-80℃, the vacuum degree is 0.01 Pa, and the time is 6-12 hours. ​ 3. The method of claim 1, wherein the IZO ceramic target is prepared by the steps of: The ball milling step uses zirconia balls as the grinding medium, the ball-to-material ratio is 10:1 to 20:1, the ball milling time is 4-8 hours, and ultrasonic dispersion is combined, the frequency is 20-40 kHz, the power is 200-400 W, and the time is 1-2 hours. ​ 4. The method for preparing the IZO ceramic target according to claim 1, characterized in that, A segmented temperature rising strategy is used in the hot-press sintering process, the initial temperature is 600-800℃ and maintained for 1-2 hours, the middle temperature is 900-1100℃ and maintained for 2-4 hours, and the final temperature is 1100-1200℃ and maintained for 1-3 hours.

5. The method of claim 1, wherein the IZO ceramic target is prepared by the steps of: The annealing treatment is performed under a nitrogen or argon atmosphere, the oxygen partial pressure is controlled at 0.001-0.1 Pa, the annealing temperature is 600-900℃, and the time is 2-6 hours. ​ 6. The method of claim 1, wherein the IZO ceramic target is prepared by the steps of: 0.01-0.1 wt% graphene nanosheets are added to the precursor mixture as auxiliary dopants.

7. An IZO ceramic target material prepared based on the preparation method in any one of claims 1-6.

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