Table of Content

15 December 2023, Volume 52 Issue 12

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Reviews

Sixty Years Research of Diamonds in Sinoma Snythetic Crystals Co., Ltd.

XUAN Zhenwu, HOU Li, WANG Hengrui, YANG Zhiqi, ZHAO Xiaobo, WANG Yubao, CHENG Gang, XU Wanfen, CAO Yanxin, ZHANG Yi, WANG Xiaoling, ZHANG Zhe, YU Haitao, WEI Huayang, TIAN Long, WANG Zenghui

2023, 52(12):  2094-2107. 

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Since the “121” project in 1963, Sinoma Snythetic Crystals Co., Ltd. participated in the research of the first synthetic diamond in China, and went through a difficult and glorious days of 60 years in the research of high temperature and high pressure synthesis of diamond, including belt press, diamond tools and chemical vapor deposition diamond. Through the efforts of several generations of hard works, great achievements have been made in the technology of diamond systhesis and the application of diamond tools in China. Researchers made great contributions to the diamond course in China. Reviewing the 60 years of development of diamond technology of Sinoma Snythetic Crystals Co., Ltd. it is expected to provide inspiration and reference for researchers in the new era in terms of the external environment responds to policy trends, scientific research, transformation of technological achievements, and developmental ideas.

Research Progress on Magnesium Aluminate Spinel Transparent Ceramic

LEI Muyun, LI Zhen, ZHANG Wei, PANG Zhenli, SHI Shuangshuang, HUANG Cunxin

2023, 52(12):  2108-2124. 

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Magnesium aluminate spinel, as an advanced transparent ceramic material, has excellent properties such as wide transmission band, high transmittance, isotropy, high hardness, high strength, high thermal conductivity, high thermal shock resistance, high corrosion resistance, and high-temperature stability. It can be widely applicated to the fields of national defense security and key high-performance equipment, such as infrared guidance windows, high Mach aircraft domes, transparent armor and photoelectronic equipment windows in extreme environments. In this paper, the basic properties and the development of magnesium aluminate spinel transparent ceramic are summarized, the research and development work of Sinoma Sythentic Crystal Co., Ltd. over the last three decades are focused on, including high-purity spinel powder synthesis, magnesium aluminate spinel transparent ceramic forming and sintering process, the performance and application.The difficulties encountered in material development and the challenges faced in the application development are analyzed. Based on these, the research directions and methods are considered, its application and development are prospected.

Research Progress of Chemical Vapor Deposition ZnS and ZnSe

ZHAO Xiaobo, WEI Zhonghua, ZHANG Xu, QIAN Xun, YU Haohai

2023, 52(12):  2125-2134. 

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Chemical vapor deposition (CVD) ZnS and ZnSe have high infrared transmittance and good optical and mechanical properties, and are the preferred infrared optical materials for infrared military detection systems. The preparation of large-sized and highly homogeneous ZnS and ZnSe materials is an important topic for future research. This article introduces the principle of chemical vapor deposition and the main problems in the accumulation process, describes the necessary optical properties of high-performance infrared materials, summarizes and analyzes the research progress of CVD ZnS and CVD ZnSe, and main defect formation mechanism of the two materials as well as the process control research. It aims to improve the production process parameters and provide theoretical reference for the batch preparation of high-performance ZnS and ZnSe materials for military applications.

Development Status and Application of Ultra-Low Expansion Glass-Ceramics

ZHAO Chunxia, JIANG Xinzhao, ZHANG Wei, LIU Jie, FAN Shigang, HE Can

2023, 52(12):  2135-2145. 

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Ultra-low expansion glass-ceramics is a kind of glass-ceramics with β-quartz solid solution as main crystal phase precipitated in parent glass after strictly controlled crystallization on the basis of Li₂O-Al₂O₃-SiO₂ system glass. Because of its low coefficient of thermal expansion, excellent thermal stability, chemical stability and mechanical properties, ultra-low expansion glass-ceramics have been widely used in many fields. In this paper, the composition, preparation method, domestic and international research process and development status, application of ultra-low expansion glass-ceramics are reviewed, and the existing problems in the production of ultra-low expansion glass-ceramics and the gap between the domestic ultra-low expansion glass-ceramics and the top international products, and the development direction of domestic ultra-low expansion glass-ceramics in the future are pointed out.

Research Articles

Growth and Properties of Large Size CLBO Single Crystal

SHI Shuangshuang, WANG Guoying, XIAO Yabo, WANG Haili, CHEN Jianrong

2023, 52(12):  2146-2150. 

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CsLiB₆O₁₀(CLBO) is a high-performance nonlinear optical crystal, particularly suitable for high-power ultraviolet laser by fourth harmonic generation (FHG, 266 nm) and fifth harmonic generation (FIHG, 210 nm). A CLBO crystal with the size of 120 mm×112 mm×62 mm was successfully grown using top seeded solution growth (TSSG) method in this work. The grown CLBO crystal exhibits a complete appearance without macroscopic defects such as cracking and visible scattering particles. A CLBO FIHG crystal component was cut from this crystal, and its UV-visible-near infrared transmittance, optical uniformity and weak absorption properties were analyzed in detail. The results include that, the mean transmittance exceeds 90% from 210 nm to 1 800 nm, optical uniformity result is 3.8×10^-5 and the weak absorption is 90×10^-6 cm^-1 at 1 064 nm. All of these results indicate that the as-grown CLBO crystal possesses good transmittance in the ultraviolet region, high optical uniformity and low weak absorption, laying the foundation for subsequent research on related applications.

Growth and Device Performance of RTP Electro-Optical Crystal

SHI Shuangshuang, SHI Ruize, WANG Guoying, XIAO Yabo, WANG Haili, CHEN Jianrong

2023, 52(12):  2151-2155. 

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Rubidium titanyl phosphate (RTP) is an electro-optical (EO) crystal with excellent comprehensive performance, which has the advantages of high electro-optic coefficient, low half-wave voltage, high laser damage threshold as well as compact device, strong environmental adaptability, etc. These characters make it become a new generation of EO materials, suitable for use as EO switches, modulators, and other EO devices. The development of laser systems urgently requires high-performance EO crystals for higher power, higher repetition rate, and narrower pulse width lasers. In this paper, the growth system with high [Rb]/[P] molar ratio was chosen, and high-quality RTP crystal was successfully synthesized by the top seeded solution growth method. Relevant properties of crystal or device were tested, containing the optical uniformity, repetition rate, insertion loss, extinction ratio and laser damage threshold. The results show that, the optical homogeneity of sample is 7.3×10^-6 cm ^-1, repetition frequency of 501 kHz, insertion loss of 0.49%, extinction ratio of 31.57 dB, and laser damage threshold of 856 MW/cm².

Growth and Scintillation Properties of Gd₃(Al,Ga)₅O₁₂∶Ce Crystal

WANG Haili, LI Hui, ZHOU Nanhao, SHI Shuangshuang, SU Jian, ZHANG Wei, CHEN Jianrong, HUANG Cunxin

2023, 52(12):  2156-2160. 

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Ce³⁺ doped gadolinium aluminum gallium garnet (GAGG∶Ce) scintillation crystal has the advantages of high light output, high energy resolution, short decay time, no self radiation and non-deliquescence, which make it has a broad application prospect in nuclear medical imaging, security inspection and environment detection et al. This paper reported the Czochralski growth and scintillation properties of GAGG∶Ce single crystal. GAGG∶Ce raw material was synthesized by high temperature solid state reaction method. By means of XRD analysis, the raw material sintered at 1 500 ℃ for 12 h is verified to be pure GAGG phase. GAGG∶Ce crystal with size of ϕ50 mm×90 mm was successfully grown by Czochralski method. The transmission spectrum, X-ray excited emission spectrum and pulse height spectrum of the crystal were tested. Results show that optical transmittance at 550 nm for the sample with thickness of 7 mm reaches as high as 81.5%. The X-ray excited emission peak central wavelength of the GAGG∶Ce crystal is located at 550 nm. The light output of the GAGG∶Ce crystal is 59 000 photons/MeV and the energy resolution is 6.2%@662 keV. The decay time is 149 ns and a slow component of 748 ns.

Growth and Properties Study of LaBr₃∶Ce,Sr Scintillation Crystal

WANG Haili, ZHOU Nanhao, XU Wanfen, ZHANG Wei, LI Huanying, HAN Jiahong, CHEN Jianrong

2023, 52(12):  2161-2166. 

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In this paper, ϕ25 mm lanthanum bromide scintillation crystals with 5%Ce³⁺ and different Sr²⁺ doping concentrations (0.1%, 0.3%, 0.5% in molar ratio) were successfully grown by spontaneous nucleation vertical Bridgman method. X-ray excited emission spectra, transmission spectra and pulse height spectra of these crystals were measured. Results show that, the emission spectra waveform of LaBr₃∶Ce crystals with different Sr²⁺ doping concentrations is basically consistent under X-ray excitation, and the emission peak shows a significant red shift compared with that of sample without Sr²⁺ doping. With the increase of Sr²⁺doping concentration, the emission peak of LaBr₃∶Ce,Sr crystal shows a slight red shift. There is no obvious absorption peak range from 350 to 800 nm of LaBr₃∶Ce,Sr crystals with different Sr²⁺ doping concentrations. Compared with LaBr₃∶Ce crystals, transmittance of 0.3% and 0.5% Sr²⁺doped LaBr₃∶Ce crystals decrease. In addition, with the increase of Sr²⁺doping concentration, the energy resolution of the crystal increases correspondingly. LaBr₃∶Ce,0.5%Sr crystal has the highest energy resolution of 2.99%@662 keV. The energy resolution of the encapsulated LaBr₃∶Ce,0.5%Sr crystal with size of ϕ25 mm×25 mm is 2.93%@662 keV.

Interfacial Structure and Diffusion Behavior of Co-Fired PMN-PT Single Crystal and Ag Electrode

ZHENG Yu, TONG Yaqi, LI Hui, ZHANG Wei, ZHANG Xuan, WANG Zhen

2023, 52(12):  2167-2173. 

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The surface of PMN-PT relaxor ferroelectric single crystal was coated with medium and high temperature Ag paste by screen printing process. Ag electrodes were prepared by rapid sintering process at 650 and 850 ℃, respectively. The microstructure of Ag electrode surface and metal-crystal interface was observed by scanning electron microscope. The distribution of elements at the interface was analyzed by energy spectrum. The Ag electrode has a thickness of tens of microns, a porous structure, and a good combination with crystals. After sintering, atoms such as Pb, Nb and Ti in the crystal migrate to the Ag electrode, and a transition layer of several microns thickness is formed at the interface after sintering of the high temperature Ag paste, which greatly reduces the migration of atoms in the crystal to the electrode. PMN-PT wafers with different crystal orientation have a strong crystal face effect during the diffusion process to the Ag electrode at high temperature, and the diffusion degree of Pb, Nb and Ti atoms in the [110] direction crystal is smaller than that in the [100] direction crystal.

Influence of Porous Graphite on SiC Crystal Growth: a Numerical Simulation Study

LI Rongzhen, ZHAO Xiaobo, WEI Huayang, LI Dan, ZHOU Zhenxiang, NI Daiqin, LI Yong, LI Hongkai, LIN Qinglian

2023, 52(12):  2174-2185. 

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SiC is the ideal material for RF devices and power devices. Resistance-heated physical vapor transport method is considered a promising way to grow large size (especially 6 and 8 inch) SiC crystals due to its temperature uniformity. In recent years, the introduction of new technique such as the use of porous graphite improved the SiC crystal quality and yield, while there are only a few relatively comprehensive studies on its mechanism. This paper made comprehensive research on the influence of porous graphite on SiC growth system by means of numerical simulation. The crystal growth experiments under numerical simulation conditions have been carried out accordingly. The numerical simulation results show that the porous graphite raises the temperature and temperature uniformity within the powder area, which can strengthen the sublimation of powder. The temperature difference between the powder and the seed inside the crucible is improved and a greater growth driving force is obtained. The effect of decrease of the re-crystallization at powder surface has also been proved. Besides, the porous graphite improves the flow stability across the whole growth process, and assures a stable crystal growth. The C/Si ratio has been increased under the influence of porous graphite, and thus reduces the probability of phase transition. The crystal shape has also been improved. The subsequent growth experiments verified the conclusions of numerical simulations such as the improvement of flow uniformity, decrease of poly-type transition probability, improvement of crystal shape, etc. The results of this paper have practical significance on comprehending the effecting mechanism of porous graphite and improving the SiC crystal growth conditions for better crystal quality.

Gallium Oxide Single Crystal: Morphology of Corrosion Pits under Acid- and Alkaline-Base Conditions

GAO Chong, WEI Jinshan, OUYANG Zheng, HE Jinghui, WANG Zenghui, BU Yuzhe, SAI Qinglin, ZHAO Peng

2023, 52(12):  2186-2195. 

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Gallium oxide crystal materials has enormous potential in the fields of power devices and optoelectronics due to its excellent performance and the advantage of being able to grow by melt method. In recent years, numerous experts at home and abroad have also started researching gallium oxide single crystal materials. High quality and low defect gallium oxide single crystal materials are extremely important for subsequent epitaxy and device preparation. At present, the mainstream growth method internationally is edge-defined film-fed growth method (EFG), which has advantages such as short growth cycle, large size, and stable growth. However, there is still great room for progress in crystal defect control. This article focuses on the morphology of corrosion pits in gallium oxide single crystals, and processes samples of gallium oxide single crystals grown by EFG. Corrosion experiments were conducted under different acid and alkali conditions. A detailed introduction was given to the different observed corrosion pit morphologies, and the impact of crystal defects on the corrosion pit morphologies was analyzed. This is of great significance for the future research on the growth mechanism of gallium oxide single crystals and crystal defects.

Characterization of AlN Single Crystal Synthesized by the Physical Vapor Transport Method

ZHOU Zhenxiang, CHEN Ning, LI Dan, SHI Shuangshuang, NI Daiqin, CHEN Jianrong, HUANG Cunxin, LI Rongzhen, WEI Huayang

2023, 52(12):  2196-2202. 

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The 14 mm×12 mm AlN single crystal is synthesized by the homoepitaxial physical vapor transport method. The crystal sample sliced from the boule is processed by lapping and chemical mechanical processes (CMP). The sample is characterized by Raman spectrometer, high resolution X-ray diffractometer, X-ray photoelectron spectrometer and photoluminescence spectrometer. The Raman results show that the full width at half maximum (FWHM) of the E₂ (high) phonon mode of Raman spectrum is 3.3 cm^-1 in the central region of the sample, and the FWHM of the E₂ (high) phonon mode of Raman spectrum is 4.3 cm^-1 in the edge of the sample, the AlN single crystal exhibits high crystal quality. The FWHM of the X-ray rocking curve increase to 100″ in the central region of the homoepitaxial growth crystal, while the FWHM of the X-ray rocking curve is 205″ in the edge region of the homoepitaxial growth crystal, which indicates defects exist in the crystal. XPS results show that there are C, O, Si impurity elements in the crystal, and the atomic concentration of the impurities is 0.74%, 1.43% and 2.14%, respectively. It is found that the mainly oxygen impurities exist in the crystal in the form of Al—O, N—Al—O bonding. PL spectra show that crystal contains V_Al-O_N compound defect and V_Al point defect.

Preparation and Properties of Low-Absorption Sapphire Crystal by Modified Kyropoulos Method

ZHAO Peng, SONG Jianjun, ZHANG Wei, CHENG Gang, ZHANG Lisheng, FU Chunlei, SHI Gang, HUANG Cunxin

2023, 52(12):  2203-2209. 

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In order to meet the demand for low-absorption sapphire crystal materials in important national defense projects in China, a self-produced crystal growth apparatus is developed in this study and the successful growth of low-absorption sapphire crystal can be achieved. The as-obtained crystal exhibits excellent transparency in the ultraviolet, visible, and near to mid-infrared wavelength ranges. The transmittance is above 83% as the wavelength in the range of 250 nm to 400 nm, while the transmittance is above 85% as the wavelength in the range of 400 nm to 4 200 nm. On the basis of the characterization tests conducted on different regions of the crystal, the average dislocation density of crystal can be determined as 253.19 cm^-2. The rocking curve shows symmetrical and sharp peaks with a full width at half maximum of 14″. In addition, it is worth noting that the light absorption coefficient of crystal is (23.3~30.4)×10^-6 cm^-1 at the wavelength of 1 064 nm, indicating that the impurity elements inside the crystal can be effectively controlled. Accordingly, the outstanding optical properties crystal can be applied in high-energy laser systems, space camera lenses and other relevant fields.

Transparent Armor Based on Sapphire Crystal Plate: an “Optical Shield” for Future Warfare

WANG Xiaoliang, ZHAO Peng, LIU Fafu, HUANG Youqi, LI Qinglian, SUN Jun, HUANG Cunxin

2023, 52(12):  2210-2214. 

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The sapphire single crystal plate with size of 485 mm×985 mm×12 mm was successfully prepared by a large-size edge-defined film-fed growth (EFG) furnace designed and developed independently. After cutting and grounding, the crystal was formed into transparent armors composited with glass and polycarbonate. The surface density with the size of 352 mm×351 mm×33 mm is 79.27 kg/m², and the surface density of the other is 79.38 kg/m² with the size of 351 mm×342 mm×33 mm. Targeting tests were conducted on the transparent armors using incendiary shells with diameters of 7.62 mm and 12.7 mm, respectively. The experimental results show that the transparent armor based on sapphire crystal plate has excellent impact resistance during firing at a normal angle of 0° and with a distance of 100 m which from target to the armors.

Preparation and Mechanical Properties of AlON Transparent Ceramics

WANG Ying, ZHANG Wei, TIAN Tingyan, HUANG Cunxin, WANG Zhen, CHEN Jianrong, SHI Shuangshuang

2023, 52(12):  2215-2221. 

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AlON transparent ceramics have broad application prospects in national defense and civil use due to its good light transmission, thermal shock stability, mechanical properties and good processability. The AlON powder were prepared in batches by an improved carbothermal reduction nitridation/fluidized bed method in this article. A single batch can prepare up to 2 kg, and no second phase was observed in the XRD patterns of AlON powder. Laser particle size analysis shows an average particle size of 1.54 μm and the particle size distribution is uniform. Green body with good uniformity and high density was obtained using the powder molded by cold isostatic pressing. AlON transparent ceramics with transmissivity of 82.3% and bending strength of 310 MPa were prepared by sintering temperature at 1 850 ℃ and nitrogen pressure of 5 MPa, which has certain practical significance for promoting the application of AlON transparent ceramics.

High-Temperature Performances of Chemical Vapor Depositon Elemental ZnS

CUI Hongmei, ZHANG Xu, CHEN Lin, SU Jian, SONG Lei, MA Tianyi, QIAN Xun, WEI Zhonghua

2023, 52(12):  2222-2227. 

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As a kind of medium and long wave infrared optical material, elemental ZnS has excellent optical and mechanical properties. At present, the development of hypersonic vehicle urgently requires research on the high-temperature performance of elemental ZnS infrared windows.The high-temperature performance of elemental ZnS at different temperatures were studied in this paper, and the results show that the emissivity of elemental ZnS increases with the increase of wavelength, and increases with the increase of temperature at the same wavelength. At 500 ℃, the average normal optical spectrum emissivity is less than 0.05 at 3～5.5 μm, and less than 0.10 at 7～10.5 μm. In the range of 2～9.5 μm, the temperature has little effect on the transmittance, but after 9.5 μm, the transmittance decreases significantly as the temperature increases. The refractive index, thermal optical coefficient, and expansion coefficient increase with increasing temperature. Temperature has almost no effect on bending strength. The elastic modulus decreases with increasing temperature, the elastic modulus at 800 ℃ decreases by about 30% compared to that at room temperature.

Growth and Optical Properties Characterization of Deep Ultraviolet High Transmittance Quartz Crystals

ZHANG Shaofeng, CAO Yancui, ZHANG Xuan, LI Dan, HU Xiao, LIU Julan, JIANG Xiuli

2023, 52(12):  2228-2234. 

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Illumination system, as one of the main parts of lithography, enables to supply high uniformity intensity distribution on the mask, controls exposure dose and creates off-axis illumination (OAI) modes, which enhance the resolution and enlarge depth of focus of lithography. Quartz crystals exhibit intrinsic birefringence in the x-direction, based on which, quartz crystal polarization device is made, and the polarization state of beam can be controlled by the device. In the lithography machine’s lighting system, the resolution ratio and imaging quality can be further improved by the polarization device with off-axis illumination modes assisted. Due to the limitations of traditional quartz crystal growth process and crystal automorphism, large-diameter quartz wave plate (diameter above 50 mm) which the polarization device need was always a challenge. In this study, optimized framework seed method was applied to eliminate heritable etch channel defects. Raw material ratio was optimized for further reduce the content of trace elements such as Al³⁺ and Na⁺, etc. Temperature-rising curve was controlled to realize lattice matching on the surface of quartz seed, and weaken inhomogeneous in the epitaxial region of quartz crystal. The parameters (such as temperature, pressure, mineralizer and its concentration, opening rate of throttle flap, et al.) were systematically adjusted for quartz growth. Thereby a high transmittance quartz single crystal suitable for 193 nm wavelength was successfully synthesized and a quartz wave plate blank with maximum size of ϕ160 mm was processed, which is the largest size quartz optical wave plate blank reported. Optical properties such as trace element content, internal transmittance, birefringence performance, optical uniformity and laser damage resistance were characterized. The results show that, the total content of trace elements in quartz crystal is controlled within 7×10^-6, the internal transmittance reaches 99.80%/mm, the unevenness of birefringence difference is less than 0.029 7%, and the PV value of optical uniformity reaches 3.9×10^-6 (effective aperture ϕ140 mm).