IZO ceramic target material and preparation method thereof

Abstract

The invention discloses an IZO ceramic target material and a preparation method thereof. The method comprises the following steps: chemically modifying praseodymium and cerium oxides through triethanolamine to form a metal-organic complex in which Pr < 4 + > and Ce < 4 + > account for 10-20wt%; mixing indium oxide, zinc oxide and the modified rare earth powder according to the atomic ratio of In to Zn to Pr to Ce of (80-95): (5-15): (0.1-2.5): (0.1-2.5), and adding graphene nanosheets; and carrying out ball milling, ultrasonic dispersion, hot pressed sintering and annealing to regulate and control oxygen partial pressure to prepare the high-performance target material.

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, and the mild temperature ensures that the proportion of Pr 4+ is controlled at 10 wt% to 20 wt%, avoiding rapid oxidation; then increasing the temperature to 60°C to 80°C, introducing cerium oxide powder in a mass ratio of 1:1 to 2:1, and reacting for 1 hour to 2 hours to form a double rare earth complex, and 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. Adding 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 powder dispersibility. Low-frequency ultrasonic waves (15 kHz to 25 kHz, 100 W to 300 W) generate local high-temperature and high-pressure microenvironments 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 by gradually increasing the temperature and holding time, particle diffusion, grain growth and defect control are promoted, 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 by accurately controlling the oxygen vacancy concentration, the electrical properties and structural stability of the IZO target material are optimized to meet the needs of high-precision thin film devices.

[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 nanosheets are added to the precursor mixture as an auxiliary dopant.

[0018] It should be noted that graphene nanosheets have high specific surface area and excellent electron transfer capacity, and are uniformly dispersed in the mixture. Through the interaction of its π electron system with the electronic structure of rare earth ions, the carrier mobility is enhanced, and its reducing property helps to regulate the oxygen vacancy concentration, balance the carrier concentration and electrical stability. During the ball milling and ultrasonic dispersion process, the graphene nanosheets further promote the uniform distribution of the particles and reduce 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, preventing abnormal grain growth caused by excessively high temperature, thereby improving the density and electrical uniformity of the target material, and meeting the needs 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 present 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 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 needs of high-precision thin film devices (such as OLED, 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 traditional IZO target resistivity regulation bottleneck, 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 does it mean an embodiment that is separate or selectively excluded from other embodiments.

[0025] EMBODIMENT EMBODIMENT 1

[0026] Step S1: Chemical modification of praseodymium oxide and cerium oxide powder. First, a 0.05 mol / L triethanolamine chelating agent solution is prepared, and praseodymium oxide and cerium oxide powder are added to the solution in a mass ratio of 1:1. Specifically, praseodymium oxide powder is first added, and the solution is reacted at 40°C for 1 hour while maintaining the pH value of the solution at 4.0 (controlled by adding 0.2 mol / L dilute hydrochloric acid), forming a praseodymium-organic complex; then the temperature is raised to 60°C, and cerium oxide powder is added, and the reaction is continued for 1 hour while adjusting the pH value of the solution to 5.5 (controlled by adding 0.2 mol / L sodium hydroxide), introducing 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 uniformity of the complexation reaction. Through this modification, Pr 4+ 10 wt% of total praseodymium ions, Ce 4+15 wt% of the 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, and a time of 6 hours to obtain the modified rare earth powder.

[0027] 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 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).

[0028] 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 10:1, and the ball milling time was 4 hours; then ultrasonic dispersion was combined, the frequency was 20 kHz, the power was 200 W, and the time was 1 hour to achieve sub-nanometer distribution of the powder particle size.

[0029] Step S4: The precursor mixture was subjected to hot-press sintering under a nitrogen inert atmosphere at 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 at an annealing temperature of 600°C for 2 hours to control the oxygen partial pressure, and the IZO ceramic target material was obtained.

[0030] Example 2

[0031] 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 maintaining the solution pH at 4.5 (controlled by adding 0.3 mol / L dilute hydrochloric acid), forming 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 adjusting the solution pH to 6.0 (controlled by adding 0.3 mol / L sodium hydroxide), introducing cerium ions to 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 molecular diffusion and complex reaction uniformity. Through this modification, Pr 4+ 12 wt% of the total praseodymium ions, Ce 4+wt% of total cerium ions. Subsequently, centrifugal separation was performed at a speed of 6000 rpm for 12 minutes, followed by vacuum drying at a temperature of 70°C, a vacuum degree of 0.01 Pa, and a time of 8 hours to obtain the modified rare earth powder.

[0032] 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 through high-speed stirring (400 rpm, 40 minutes).

[0033] 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 powder particle size.

[0034] Step S4: The precursor mixture was subjected to hot-press sintering under an argon inert atmosphere at a pressure of 30 MPa. A staged temperature rising strategy was adopted: the initial temperature was 700°C for 1.5 hours, the middle 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 at an annealing temperature of 750°C for 4 hours to control the oxygen partial pressure, and the IZO ceramic target material was obtained.

[0035] Example 3

[0036] 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), forming 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), introducing cerium ions to 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.

[0037] 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).

[0038] 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.

[0039] 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.

[0040] Example 4

[0041] 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.

[0042] 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 proportion 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).

[0043] 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.

[0044] 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.

[0045] Comparative Example

[0046] Comparative Example 1 Comparative Example 1 is compared with Example 1, in Step S1, only praseodymium oxide is used for chemical modification, and cerium oxide is omitted, while the total rare earth content is kept consistent.

[0047] Comparative Example 2 Comparative Example 2 is compared with Example 1, in Step S1, only cerium oxide is used for chemical modification, and praseodymium oxide is omitted, while the total rare earth content is kept consistent.

[0048] Comparative Example 3 Comparative Example 3 is compared with Example 1, in Step S1, the chemical modification process of praseodymium oxide and cerium oxide powder is omitted (i.e. no use of triethanolamine chelating agent, dynamic pH control, low-frequency ultrasonic wave and polyethylene glycol surfactant), and the original praseodymium oxide and cerium oxide powder is directly used.

[0049] Comparative Example 4 This Comparative Example 3 is compared to Example 1, except that 0.01 wt% of graphene nanoplatelets is omitted as an auxiliary dopant.

[0050] Performance Test Methods 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.

[0051] 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 conducted at room temperature (25°C), and the sample surface needs to be polished and cleaned to remove the oxide layer to ensure accurate results.

[0052] 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 conducted 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.

[0053] Table 1

[0054] 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 to 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 These red shifts indicate that the molecule forms a coordination bond with Pr and Ce, resulting in an increase in bond length and a decrease in vibration frequency. In addition, new absorption peaks appear in the Pr / Ce-complex + PEG spectrum, such as about 1125 cm -1The PEG C-O-C stretching vibration peak at 1080 cm"1 and the PEG end O-H stretching vibration peak at 3410 cm"1 further supported the complex formation of PEG with Pr / Ce complex. The difference in the intensity and width of the peaks also reflected the complex coordination environment and the enhancement of intermolecular interaction, thus confirming the successful synthesis of Pr / Ce complex.

[0055] As can be seen in connection 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.

[0056] As can be seen in connection 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 Pr and Ce double rare earth, 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 state, increasing the carrier concentration, while Ce 4+With strong oxygen affinity, it stabilizes the distribution of oxygen vacancies and prevents fluctuations in electrical properties. The synergistic effect of the two optimizes the balance between oxygen vacancy concentration and carrier mobility, enhances the density and conductivity of the target material, significantly improves the electrical performance, and meets the needs of high-precision thin film devices.

[0057] Combining Example 1, Comparative Example 3 and Table 1, it can be seen that the density of Example 1 is 7.00 g / cm 3 (98.6%), the resistivity is 2.5×10 -4 Ω·cm, and the carrier concentration is 1.8×10 20 cm -3 , with a mobility of 35 cm 2 / V·s; the density of control example 3 (no chemical modification, direct use of original praseodymium and cerium oxides) is 6.80 g / cm 3 (95.8%), resistivity is 5.0×10 -4 Ω·cm, the carrier concentration is 0.8×10 20 cm -3 , with a mobility of 20 cm 2 / V·s. Example 1 is significantly superior to Control Example 3 in terms of density and electrical properties (resistivity, carrier concentration, mobility). Example 1 uses triethanolamine (TEA) to chemically modify the metal-organic complex of Pr and Ce, combined with low-frequency ultrasound and polyethylene glycol (PEG) dispersion to optimize the uniformity and particle size of the powder and improve the density during the sintering process; Pr 4+ and Ce 4+ (each accounting for 10-20wt%) to coordinately regulate oxygen vacancies, Pr 4+ Increase carrier concentration, Ce 4+ The oxygen vacancy distribution is stabilized, enhancing the stability of electrical properties. Graphene nanosheets (0.01 wt%) further promote electron transfer, reduce resistivity, and increase mobility. The lack of chemical modification in Control Example 3 leads to particle agglomeration and uneven oxygen vacancy distribution, significantly reducing density and electrical properties, and failing to meet the requirements of high-precision thin-film devices.

[0058] Combining the data of Example 1, Comparative Example 4 and Table 1, the performance of the IZO ceramic target of Example 1 is better than that of Comparative Example 4. The density of Example 1 is 7.00 g / cm 3 (98.6%), the resistivity is 2.5×10 -4 Ω·cm, and the carrier concentration is 1.8×10 20 cm -3 , with a mobility of 35 cm 2 / V·s; while the density of control example 4 (omitted 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.

[0059] 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, characterized in that: The preparation method comprises the following steps: Step S1. Chemically modifying praseodymium oxide and cerium oxide powders to form a metal-organic complex through the coordination of a chelating agent with praseodymium ions and cerium ions, and obtaining modified rare earth powder by centrifugal separation and vacuum drying, wherein Pr 4+ and Ce 4+ Each accounts for 10 wt% to 20 wt% of the total praseodymium ions and the total cerium ions; Step S2. Indium oxide, zinc oxide, and the modified rare earth powder are mixed in a predetermined ratio to form a precursor mixture, wherein the predetermined ratio is an atomic ratio of In:Zn:Pr:Ce of (80-95):(5-15):(0.1-2.5):(0.1-2.5), and the purity of the indium oxide, zinc oxide, praseodymium oxide, and cerium oxide powders is ≥99.99% and the initial particle size is 50 nm to 200 nm; Step S3. homogenizing the precursor mixture at the nanoscale by ball milling and ultrasonic dispersion; Step S4. Hot pressing and sintering the precursor mixture in an inert atmosphere at a temperature of 800° C. to 1200° C. and a pressure of 20 MPa to 50 MPa, and performing subsequent annealing to regulate the oxygen partial pressure to obtain the IZO ceramic target.

2. The method for preparing an IZO ceramic target according to claim 1, wherein: The chemical modification step includes: adding praseodymium oxide and cerium oxide powders in a mass ratio of 1:1 to 2:1 stepwise to 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 to 2 hours to form a praseodymium-organic complex, then heating to 60°C to 80°C and reacting for 1 to 2 hours to introduce cerium ions to form a double rare earth complex; simultaneously adding a polyethylene glycol surfactant with a mass fraction of 0.1wt% to 0.5wt%, and using low-frequency ultrasound with a frequency of 15 kHz to 25 kHz and a power of 100 W to 300 W.

3. The method for preparing an IZO ceramic target according to claim 2, wherein: In the chemical modification step, the pH value of the solution is dynamically controlled to first maintain the pH value between 4.0 and 5.0 to form a praseodymium-organic complex, and then adjusted to a pH value between 5.5 and 6.5 to introduce cerium ions.

4. The method for preparing an IZO ceramic target according to claim 1, wherein: 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.

5. The method for preparing an IZO ceramic target according to claim 1, wherein: The ball milling step uses zirconia balls as grinding media, with a ball-to-material ratio of 10:1 to 20:1, and a ball milling time of 4 to 8 hours, combined with ultrasonic dispersion, with a frequency of 20 kHz to 40 kHz, a power of 200 W to 400 W, and a time of 1 to 2 hours.

6. The method for preparing an IZO ceramic target according to claim 1, wherein: The hot pressing sintering process adopts a staged temperature increase strategy, with the initial temperature of 600°C to 800°C maintained for 1 to 2 hours, the middle temperature of 900°C to 1100°C maintained for 2 to 4 hours, and the final temperature of 1100°C to 1200°C maintained for 1 to 3 hours.

7. The method for preparing an IZO ceramic target according to claim 1, wherein: The annealing treatment is performed in a nitrogen or argon atmosphere, with the oxygen partial pressure controlled at 0.001 Pa to 0.1 Pa, the annealing temperature at 600° C. to 900° C., and the annealing time at 2 hours to 6 hours.

8. The method for preparing an IZO ceramic target according to claim 1, wherein: 0.01 wt% to 0.1 wt% of graphene nanosheets are added to the precursor mixture as an auxiliary dopant.

9. An IZO ceramic target prepared by the preparation method according to any one of claims 1 to 8.

Images