Preparation method of wide-band-gap optical crystal sodium potassium fluosilicate and application of wide-band-gap optical crystal sodium potassium fluosilicate in deep ultraviolet optical window device
The KNaSiF6 crystal prepared by hydrothermal cation replacement crystallization method has a band gap of 10.11eV, solving the problem of insufficient band gap of existing deep ultraviolet window devices, achieving light transmission performance in the range of 123nm-3500nm, and avoiding the complexity and corrosion risks of traditional processes through clean and environmentally friendly preparation methods.
Patent Information
- Application Number
- CN202510227284.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-27
- Publication Date
- 2025-05-23
AI Technical Summary
When existing deep ultraviolet window devices operate in the band less than 125nm, the band gap of the material is insufficient, which cannot meet the application needs below 137nm. At the same time, the traditional preparation methods have problems such as complex process, incomplete reactions and the use of highly corrosive HF solutions.
KNaSiF6 crystals are prepared by hydrothermal cation replacement crystallization method. This method is clean and environmentally friendly, simple to operate, and can efficiently grow large-size and high-quality KNaSiF6 crystals with a band gap of 10.11 eV.
The light transmission performance of deep ultraviolet window devices in the range of 123nm-3500nm is achieved, and suitable materials are provided for deep ultraviolet optical window devices, which solves the problems of insufficient material band gap and complex preparation process, while avoiding the corrosion risk of HF solution.
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Figure CN120026392A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of optical materials, and in particular relates to a method for preparing a centrosymmetric wide bandgap crystal potassium sodium fluorosilicate, and application of the method in a deep ultraviolet optical window device. Background Art
[0002] Deep ultraviolet window devices have key applications in many important fields, including: lithography technology, used in extreme ultraviolet lithography machines, to manufacture smaller process nodes and more integrated chips; microscopes and spectrometers, used to obtain spectral images with higher spatial resolution and time; deep ultraviolet lasers, higher precision laser micro-nano processing devices, etc. In addition, deep ultraviolet window devices play an irreplaceable role in defense fields such as missile precision guidance, space-based early warning systems, and high-energy laser weapons. At the same time, they provide important observation methods for cutting-edge sciences such as stellar evolution research and interstellar matter detection. As the "eyes" of the deep ultraviolet optical system, the performance of deep ultraviolet window devices directly determines the technical upper limit of the entire system.
[0003] However, to realize the operation of devices in the deep ultraviolet band less than 125nm, the material needs to have an ultra-wide band gap of at least 10eV. 2 Taking crystal as an example, its band gap of 9.0eV can meet the conventional long-wavelength deep ultraviolet requirements, but its deep ultraviolet cutoff edge is only 137nm, which cannot meet the application requirements below 137nm. Fluorosilicate system has a larger band gap, among which KNaSiF 6 The band gap of the crystal exceeds 10 eV, but KNaSiF 6 The traditional preparation method of crystals requires HF solution, which often has problems such as complex process flow, incomplete reaction, and difficulty in ensuring crystal quality. In addition, HF solution is a highly corrosive and highly toxic chemical substance. If it is not handled properly, it will pose a serious threat to the health of the experimenters. This patent breaks through the technical route of the traditional hydrofluoric acid corrosion precipitation method and innovatively develops a hydrothermal cation replacement crystallization method to prepare KNaSiF 6 The crystal has a band gap of 10.11 eV. The synthesis method is clean and environmentally friendly, simple to operate, has high crystal quality and large size, and the yield based on silicon element exceeds 65.9%. It can synthesize large-size and high-quality single crystals at low cost and on a large scale, providing suitable materials for deep ultraviolet optical window devices. Summary of the invention
[0004] The object of the present invention is to provide a potassium sodium fluorosilicate wide bandgap optical crystal.
[0005] Another object of the present invention is to provide a method for preparing the potassium sodium fluorosilicate wide bandgap optical crystal.
[0006] Another object of the present invention is to provide a deep ultraviolet window device of potassium sodium fluorosilicate wide bandgap optical crystal and its use.
[0007] The wide-bandgap optical crystal of potassium sodium fluorosilicate described in the present invention has a chemical formula of KNaSiF 6 , the crystal has a symmetry center, belongs to the orthorhombic system, space group Pnma, and the unit cell parameters are α=90°,β=90°,γ=90°,Z=4, the unit cell volume is
[0008] The potassium sodium fluorosilicate wide bandgap optical crystal is grown by a hydrothermal cation replacement crystallization method, and the specific steps are as follows:
[0009] a.Na 2 SiF 6 Mix them with KCl in a molar ratio of 1:1, and weigh a certain amount of each to ensure that the ion replacement reaction proceeds fully.
[0010] b. Place the weighed raw materials into a 25 ml polytetrafluoroethylene liner, add deionized water at a filling degree of 10%-80%, cover the liner, place the polytetrafluoroethylene liner into the 304 stainless steel shell and tighten it.
[0011] c. Place the hydrothermal kettle in a step temperature-controlled forced air drying oven, raise the temperature to 120-240°C at 2-5°C / min, and keep it warm for 72h-120h.
[0012] d. Cool down at a rate of 30°C / h. After cooling to room temperature, open the polytetrafluoroethylene liner, rinse the product with deionized water, and dry the washed crystal product in a drying oven to obtain KNaSiF 6 Crystal.
[0013] Use of the potassium sodium fluorosilicate crystal deep ultraviolet window device, KNaSiF 6 The working principle of the crystal deep ultraviolet window device is that the incident electromagnetic wave passes through the processed KNaSiF 6 The incident electromagnetic wave has a transmission range of 123 nm to 3500 nm. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 The Pnma phase KNaSiF 6 Schematic diagram of the crystal structure, showing the projection of K, Na, Si, and F along the b direction.
[0015] Figure 2 The Pnma phase KNaSiF 6 Schematic diagram of the crystal structure, showing the projection of K, Na, Si, and F along the c direction.
[0016] Figure 3 The Pnma phase KNaSiF 6 Schematic diagram of X-ray diffraction of a single crystal after it is ground into powder.
[0017] Figure 4 The Pnma phase KNaSiF 6 Schematic diagram of energy bands calculated by crystal theory.
[0018] Figure 5 P3 in the ICSD standard database 1 21 phase SiO 2 Schematic diagram of energy bands calculated by crystal theory.
[0019] Figure 6 The Pnma phase KNaSiF grown by the hydrothermal cation replacement crystallization method of the present invention 6 Crystal.
[0020] Figure 7 The Pnma phase KNaSiF 6 Deep ultraviolet window devices prepared by crystal. DETAILED DESCRIPTION
[0021] The technical content, achieved objectives and effects of the present invention are described in detail below in conjunction with the implementation and drawings.
[0022] Example 1
[0023] Hydrothermal cation replacement crystallization method to grow potassium sodium fluorosilicate crystals:
[0024] a. Mix in a molar ratio of 1:1, weigh 0.470g Na 2 SiF 6 and 0.185 g KCl.
[0025] b. Place the weighed raw materials into a 25 ml polytetrafluoroethylene liner, then add 5 ml of deionized water at a filling degree of 20%, cover the liner tightly, and place it into the 304 stainless steel shell of the hydrothermal kettle and tighten it.
[0026] c. Place the hydrothermal kettle in a step temperature-controlled forced air drying oven, raise the temperature to 120°C at 2°C / min, and keep it warm for 120 hours.
[0027] d. Cooling at a rate of 30°C / h, opening the polytetrafluoroethylene liner after cooling to room temperature, washing the product with deionized water, and drying the washed crystal product in a drying oven to obtain potassium sodium fluorosilicate crystals.
[0028] Example 2
[0029] Hydrothermal cation replacement crystallization method to grow potassium sodium fluorosilicate crystals:
[0030] a. Mix in a molar ratio of 1:1 and weigh 0.658g Na 2 SiF 6 and 0.259 g KCl.
[0031] b. Place the weighed raw materials into a 25 ml polytetrafluoroethylene liner, then add 5 ml of deionized water at a filling degree of 20%, cover the liner tightly, and place it into the 304 stainless steel shell of the hydrothermal kettle and tighten it.
[0032] c. Place the hydrothermal kettle in a step temperature-controlled forced air drying oven, raise the temperature to 140°C at 2.5°C / min, and keep it warm for 120 hours.
[0033] d. Cooling at a rate of 30°C / h, opening the polytetrafluoroethylene liner after cooling to room temperature, washing the product with deionized water, and drying the washed crystal product in a drying oven to obtain potassium sodium fluorosilicate crystals.
[0034] Example 3
[0035] Hydrothermal cation replacement crystallization method to grow potassium sodium fluorosilicate crystals:
[0036] a. Mix in a molar ratio of 1:1, weigh 0.940g Na 2 SiF 6 and 0.370 g KCl
[0037] b. Place the weighed raw materials into a 25 ml polytetrafluoroethylene liner, then add 5 ml of deionized water at a filling degree of 20%, cover the liner tightly, and place it into the 304 stainless steel shell of the hydrothermal kettle and tighten it.
[0038] c. Place the hydrothermal autoclave in a step temperature-controlled forced air drying oven, raise the temperature to 160°C at 3°C / min, and keep it warm for 96 hours.
[0039] d. Cooling at a rate of 30°C / h, opening the polytetrafluoroethylene liner after cooling to room temperature, washing the product with deionized water, and drying the washed crystal product in a drying oven to obtain potassium sodium fluorosilicate crystals.
[0040] Example 4
[0041] Hydrothermal cation replacement crystallization method to grow potassium sodium fluorosilicate crystals:
[0042] a. Mix in a 1:1 molar ratio and weigh 1.128g Na 2 SiF 6 and 0.444 g KCl.
[0043] b. Place the weighed raw materials into a 25 ml polytetrafluoroethylene liner, then add 5 ml of deionized water at a filling degree of 20%, cover the liner tightly, and place it into the 304 stainless steel shell of the hydrothermal kettle and tighten it.
[0044] c. Place the hydrothermal kettle in a step temperature-controlled forced air drying oven, raise the temperature to 180°C at 3°C / min, and keep it warm for 96 hours.
[0045] d. Cooling at a rate of 30°C / h, opening the polytetrafluoroethylene liner after cooling to room temperature, washing the product with deionized water, and drying the washed crystal product in a drying oven to obtain potassium sodium fluorosilicate crystals.
[0046] Example 5
[0047] Hydrothermal cation replacement crystallization method to grow potassium sodium fluorosilicate crystals:
[0048] a. Mix in a 1:1 molar ratio and weigh 1.410 g Na 2 SiF 6 and 0.555 g KCl.
[0049] b. Place the weighed raw materials into a 25 ml polytetrafluoroethylene liner, then add 5 ml of deionized water at a filling degree of 20%, cover the liner tightly, and place it into the 304 stainless steel shell of the hydrothermal kettle and tighten it.
[0050] c. Place the hydrothermal autoclave in a step temperature-controlled forced air drying oven, raise the temperature to 200°C at 3.5°C / min, and keep it warm for 96 hours.
[0051] d. Cooling at a rate of 30°C / h, opening the polytetrafluoroethylene liner after cooling to room temperature, washing the product with deionized water, and drying the washed crystal product in a drying oven to obtain potassium sodium fluorosilicate crystals.
[0052] Example 6
[0053] Hydrothermal cation replacement crystallization method to grow potassium sodium fluorosilicate crystals:
[0054] a. Mix in a 1:1 molar ratio and weigh 1.598g Na 2 SiF 6 and 0.629 g KCl.
[0055] b. Place the weighed raw materials into a 25 ml polytetrafluoroethylene liner, then add 5 ml of deionized water at a filling degree of 20%, cover the liner tightly, and place it into the 304 stainless steel shell of the hydrothermal kettle and tighten it.
[0056] c. Place the hydrothermal kettle in a step temperature-controlled forced air drying oven, raise the temperature to 220°C at 4°C / min, and keep it warm for 72 hours.
[0057] d. Cooling at a rate of 30°C / h, opening the polytetrafluoroethylene liner after cooling to room temperature, washing the product with deionized water, and drying the washed crystal product in a drying oven to obtain potassium sodium fluorosilicate crystals.
[0058] Example 7
[0059] Hydrothermal cation replacement crystallization method to grow potassium sodium fluorosilicate crystals:
[0060] a. Mix in a 1:1 molar ratio and weigh 1.880g Na 2 SiF 6 and 0.74 g KCl.
[0061] b. Place the weighed raw materials into a 25 ml polytetrafluoroethylene liner, then add 5 ml of deionized water at a filling degree of 20%, cover the liner tightly, and place it into the 304 stainless steel shell of the hydrothermal kettle and tighten it.
[0062] c. Place the hydrothermal kettle in a step temperature-controlled forced air drying oven, raise the temperature to 240°C at 5°C / min, and keep it warm for 72 hours.
[0063] d. Cooling at a rate of 30°C / h, opening the polytetrafluoroethylene liner after cooling to room temperature, washing the product with deionized water, and drying the washed crystal product in a drying oven to obtain potassium sodium fluorosilicate crystals.
[0064] Example 8
[0065] Hydrothermal cation replacement crystallization method to grow potassium sodium fluorosilicate crystals:
[0066] a. Mix in a molar ratio of 1:1, weigh 2.068g Na 2 SiF 6 and 0.814 g KCl.
[0067] b. Place the weighed raw materials into a 25 ml polytetrafluoroethylene liner, then add 2.5 ml of deionized water at a filling degree of 10%, cover the liner tightly, and place it into the 304 stainless steel shell of the hydrothermal kettle and tighten it.
[0068] c. Place the hydrothermal autoclave in a step temperature-controlled forced air drying oven, raise the temperature to 240°C at 2°C / min, and keep it warm for 72 hours.
[0069] d. Cooling at a rate of 30°C / h, opening the polytetrafluoroethylene liner after cooling to room temperature, washing the product with deionized water, and drying the washed crystal product in a drying oven to obtain potassium sodium fluorosilicate crystals.
[0070] Example 9
[0071] Hydrothermal cation replacement crystallization method to grow potassium sodium fluorosilicate crystals:
[0072] a. Mix in a 1:1 molar ratio and weigh 2.350g Na 2 SiF 6 and 0.925 g KCl.
[0073] b. Place the weighed raw materials into a 25 ml polytetrafluoroethylene liner, then add 10 ml of deionized water at a filling degree of 40%, cover the liner tightly, and place it into the 304 stainless steel shell of the hydrothermal kettle and tighten it.
[0074] c. Place the hydrothermal autoclave in a step temperature-controlled forced air drying oven, raise the temperature to 240°C at 3°C / min, and keep it warm for 96 hours.
[0075] d. Cooling at a rate of 30°C / h, opening the polytetrafluoroethylene liner after cooling to room temperature, washing the product with deionized water, and drying the washed crystal product in a drying oven to obtain potassium sodium fluorosilicate crystals.
[0076] Example 10
[0077] Hydrothermal cation replacement crystallization method to grow potassium sodium fluorosilicate crystals:
[0078] a. Mix in a 1:1 molar ratio and weigh 2.538g Na 2 SiF 6 and 0.999 g KCl.
[0079] b. Place the weighed raw materials into a 25 ml polytetrafluoroethylene liner, then add 15 ml of deionized water at a filling degree of 60%, cover the liner tightly, and place it into the 304 stainless steel shell of the hydrothermal kettle and tighten it.
[0080] c. Place the hydrothermal kettle in a step temperature-controlled forced air drying oven, raise the temperature to 240°C at 4°C / min, and keep it warm for 96 hours.
[0081] d. Cooling at a rate of 30°C / h, opening the polytetrafluoroethylene liner after cooling to room temperature, washing the product with deionized water, and drying the washed crystal product in a drying oven to obtain potassium sodium fluorosilicate crystals.
[0082] Embodiment 11
[0083] Hydrothermal cation replacement crystallization method to grow potassium sodium fluorosilicate crystals:
[0084] a. Mix in a 1:1 molar ratio and weigh 2.820g Na 2 SiF 6 and 1.110 g KCl.
[0085] b. Place the weighed raw materials into a 25 ml polytetrafluoroethylene liner, then add 20 ml of deionized water at a filling degree of 80%, cover the liner tightly, and place it into the 304 stainless steel shell of the hydrothermal kettle and tighten it.
[0086] c. Place the hydrothermal kettle in a step temperature-controlled forced air drying oven, raise the temperature to 240°C at 5°C / min, and keep it warm for 120 hours.
[0087] d. Cooling at a rate of 30°C / h, opening the polytetrafluoroethylene liner after cooling to room temperature, washing the product with deionized water, and drying the washed crystal product in a drying oven to obtain potassium sodium fluorosilicate crystals.
[0088] Implement any one of 1-11 sodium fluorosilicate wide band gap optical crystals, the resulting chemical formula is KNaSiF6, the crystal has a symmetry center, belongs to the orthorhombic system, the space group is Pnma, and the unit cell parameters are α=90°,β=90°,γ=90°,Z=4, the unit cell volume is The structure of the crystal is shown in Figure 1 and Figure 2 , X-ray diffraction diagram is shown in Figure 3 .
[0089] Example 12
[0090] Accurate calculation of the energy band of potassium sodium fluorosilicate optical crystal:
[0091] Any KNaSiF from 1 to 11 will be implemented 6 The crystal structure data obtained from the crystal was calculated using the Castep module of Materialsstudio software in reciprocal space and modulus-conserving pseudopotential conditions using the ultra-high precision PEB0 hybrid functional. The calculation results are shown in Figure 4 .
[0092] According to Planck's formula in quantum mechanics, the relationship between the energy E of a photon and its wavelength λ is:
[0093] in:
[0094] E is the energy of the photon (unit: eV)
[0095] h is Planck's constant (6.626×10 -34 J.s)
[0096] c is the speed of light (3.0×10 8 m / s)
[0097] λ is the wavelength of light (unit: nm)
[0098] Substituting the constants in the formula and converting the units, we get:
[0099] FWf 6 The theoretical band gap obtained by crystal calculation is 10.11eV, and the corresponding deep ultraviolet cutoff absorption edge is 122.65nm. However, due to the discontinuity of the electron wave function selected for theoretical calculation, the theoretical band gap is smaller than the actual band gap, and the corresponding deep ultraviolet cutoff edge is larger. The known P3 is derived from the ICSD standard database 1 21 phase SiO 2 The standard crystal structure data file of the crystal, using the same theoretical parameters, is compared with the calculated P3 1 21 phase SiO 2 The crystal band gap is calculated as follows: Figure 5 The theoretical band gap value is 8.831eV (corresponding to the deep ultraviolet cutoff absorption edge of 140.30nm), while the actual band gap value is 9.00eV (corresponding to the deep ultraviolet absorption edge of 137.67nm). The calculation error is only 1.9%, and the calculation result is relatively accurate. 6 The band theory calculations are accurate.
[0100] Example 13
[0101] Deep ultraviolet devices based on potassium sodium fluorosilicate crystals:
[0102] The potassium sodium fluorosilicate crystals (greater than 2.67×1.04×1.02 mm) grown in Example 1-11 were 3 ),like Figure 6 As shown, after optical processing, it is used to make a deep ultraviolet window device. The schematic diagram of the deep ultraviolet window device is as follows Figure 7 The incident electromagnetic wave passes through the optically processed potassium sodium fluorosilicate crystal to obtain a transmitted electromagnetic wave, and its transmission wavelength range is 123nm-3500nm.
Claims
1. A potassium sodium fluorosilicate deep ultraviolet optical crystal, characterized in that: The chemical formula is KNaSiF6, with a centrosymmetric structure, belonging to the orthorhombic crystal system, the space group is Pnma, and the unit cell parameters are α=β=γ=90°,Z=4,unit cell volume 2. The method for preparing the sodium potassium fluorosilicate deep ultraviolet optical crystal according to claim 1, characterized in that: The KNaSiF6 crystals were grown using the hydrothermal cation replacement method: The hydrothermal cation replacement method for growing KNaSiF6 crystals comprises the following steps: a. Mix Na2SiF6 and KCl in a molar ratio of 1:1, and weigh a certain amount of each to ensure that the ion replacement reaction proceeds fully. b. Put the weighed raw materials into the PTFE liner, then add deionized water at a filling degree of 10%-80%, cover the liner, put the PTFE liner into the 304 stainless steel shell and tighten it. c. Place the hydrothermal kettle in a step temperature-controlled forced air drying oven, raise the temperature to 120-240°C at 2-5°C / min, and keep it at this temperature for 72h-120h. d. Cool down at a rate of 30°C / h. After cooling to room temperature, open the polytetrafluoroethylene liner, rinse the product with deionized water, and place the washed crystal product in a drying oven to dry to obtain KNaSiF6 crystals.
3. The preparation method according to claim 2, characterized in that: The molar ratio of Na2SiF6 to KCl in step a is 1:1, the filling degree in step b is 10%-80%, the heating rate in step c is 2-5°C / min, the maximum reaction temperature is 120-240°C, and the insulation time is 72h-120h.
4. The potassium sodium fluorosilicate optical crystal according to claim 1, characterized in that: Its theoretical band gap is 10.11 eV, corresponding to a deep ultraviolet cutoff absorption edge of 123 nm.
5. The use of the potassium sodium fluorosilicate optical crystal in the preparation of deep ultraviolet optical window devices according to claim 1, characterized in that: The device is suitable for optical window devices with a light transmission band wavelength of 123nm-3500nm, especially a deep ultraviolet optical window device of 123nm-200nm.