By using Tb407 and MoO3 as starting materials, ferroelectric Tb2（MoO4）3 crystal was grown by the Czochralski method. The as-grown crystal was pale green color, transparent and crack-free. X-ray powder diffraction （...By using Tb407 and MoO3 as starting materials, ferroelectric Tb2（MoO4）3 crystal was grown by the Czochralski method. The as-grown crystal was pale green color, transparent and crack-free. X-ray powder diffraction （XRPD）, transmission spectrum, dielectric constant and polarization-electric field （P-E） hysteresis loop measurements were performed to characterize the crystal. The XRPD confirmed the as-grown crystal to be Tb2（MoO4）3. The transmission spectrum of the crystal showed that its transmittance in the entire visible and most near-infrared region was more than 70% except for an absorption peak around 486 nm. Obvious dielectric anomaly could be observed at low frequencies with increasing temperature through the dielectric constant measurement and the Curie temperature of Tb2（MoO4）3 crystal was determined to be 162.3℃ The unsaturated P-E hysteresis loops indicated that it was difficult for the ferroelectric domains in Tb2（MoO4）3 crystal to array regularly with repeated switching of the electric field.展开更多
A global analysis of heat transfer and fluid flow in a real Czochralski single silicon crystal furnace is developed using the FLUENT package.Good agreement was obtained for comparisons of the power and crystal growth ...A global analysis of heat transfer and fluid flow in a real Czochralski single silicon crystal furnace is developed using the FLUENT package.Good agreement was obtained for comparisons of the power and crystal growth speed between the simulation and experimental data,and the effect of the length of the crystal on heat transfer and fluid flow was analyzed.The results showed that T_（max） increases and its location moves downward as the crystal length increases.The flow pattern in the melt does not change until the crystal grows to 900 mm.As the crystal length increases,the flow pattern in the first gas area only changes when the crystal length is less than 700 mm,but the flow pattern in the second area changes throughout the growth process.展开更多
The fluctuation of temperature and flow in the melt is responsible for striations in the formed crystal.The purpose of this.paper is to study the instability of the Marangoni flow with numerical simulation.The driving...The fluctuation of temperature and flow in the melt is responsible for striations in the formed crystal.The purpose of this.paper is to study the instability of the Marangoni flow with numerical simulation.The driving force considered in the flow is the surface tension only. The results show Marangoni flow is one of the factors that cause striations in the formed crystal.展开更多
Pulling growth technique serves as a popular method to grow congruent melting single crystals with multiscale sizes ranging from micrometers to centimeters.In order to obtain high quality single crystals,the crystal c...Pulling growth technique serves as a popular method to grow congruent melting single crystals with multiscale sizes ranging from micrometers to centimeters.In order to obtain high quality single crystals,the crystal constituents would be arranged at the lattice sites by precisely controlling the crystal growth process.Growing interface is the position where the phase transition of crystal constituents occurs during pulling growth process.The precise control of energy at the growing interface becomes a key technique in pulling growth.In this work,we review some recent advances of pulling technique towards rare earth single crystal growth.In Czochralski pulling growth,the optimized growth parameters were designed for rare earth ions doped Y_3Al_5O_(12)and Ce:(Lu_(1-x)Y_x)_2Si O_5on the basis of anisotropic chemical bonding and isotropic mass transfer calculations at the growing interface.The fast growth of high quality rare earth single crystals is realized by controlling crystallization thermodynamics and kinetics in different size zones.On the other hand,the micro pulling down technique can be used for high throughput screening novel rare earth optical crystals.The growth interface control is realized by improving the crucible bottom and temperature field,which favors the growth of rare earth crystal fibers.The rare earth laser crystal fiber can serve as another kind of laser gain medium between conventional bulk single crystal and glass fiber.The future work on pulling technique might focus on the mass production of rare earth single crystals with extreme size and with the size near that of devices.展开更多
基金supported by the National Natural Science Foundation of China (50590401)
文摘By using Tb407 and MoO3 as starting materials, ferroelectric Tb2（MoO4）3 crystal was grown by the Czochralski method. The as-grown crystal was pale green color, transparent and crack-free. X-ray powder diffraction （XRPD）, transmission spectrum, dielectric constant and polarization-electric field （P-E） hysteresis loop measurements were performed to characterize the crystal. The XRPD confirmed the as-grown crystal to be Tb2（MoO4）3. The transmission spectrum of the crystal showed that its transmittance in the entire visible and most near-infrared region was more than 70% except for an absorption peak around 486 nm. Obvious dielectric anomaly could be observed at low frequencies with increasing temperature through the dielectric constant measurement and the Curie temperature of Tb2（MoO4）3 crystal was determined to be 162.3℃ The unsaturated P-E hysteresis loops indicated that it was difficult for the ferroelectric domains in Tb2（MoO4）3 crystal to array regularly with repeated switching of the electric field.
基金supported by the Jiangsu Zhongli PV Technology Co.,Ltd
文摘A global analysis of heat transfer and fluid flow in a real Czochralski single silicon crystal furnace is developed using the FLUENT package.Good agreement was obtained for comparisons of the power and crystal growth speed between the simulation and experimental data,and the effect of the length of the crystal on heat transfer and fluid flow was analyzed.The results showed that T_（max） increases and its location moves downward as the crystal length increases.The flow pattern in the melt does not change until the crystal grows to 900 mm.As the crystal length increases,the flow pattern in the first gas area only changes when the crystal length is less than 700 mm,but the flow pattern in the second area changes throughout the growth process.
文摘The fluctuation of temperature and flow in the melt is responsible for striations in the formed crystal.The purpose of this.paper is to study the instability of the Marangoni flow with numerical simulation.The driving force considered in the flow is the surface tension only. The results show Marangoni flow is one of the factors that cause striations in the formed crystal.
基金supported by Jilin Province Science and Technology Development Project(Grant No.21521092JH)
文摘Pulling growth technique serves as a popular method to grow congruent melting single crystals with multiscale sizes ranging from micrometers to centimeters.In order to obtain high quality single crystals,the crystal constituents would be arranged at the lattice sites by precisely controlling the crystal growth process.Growing interface is the position where the phase transition of crystal constituents occurs during pulling growth process.The precise control of energy at the growing interface becomes a key technique in pulling growth.In this work,we review some recent advances of pulling technique towards rare earth single crystal growth.In Czochralski pulling growth,the optimized growth parameters were designed for rare earth ions doped Y_3Al_5O_(12)and Ce:(Lu_(1-x)Y_x)_2Si O_5on the basis of anisotropic chemical bonding and isotropic mass transfer calculations at the growing interface.The fast growth of high quality rare earth single crystals is realized by controlling crystallization thermodynamics and kinetics in different size zones.On the other hand,the micro pulling down technique can be used for high throughput screening novel rare earth optical crystals.The growth interface control is realized by improving the crucible bottom and temperature field,which favors the growth of rare earth crystal fibers.The rare earth laser crystal fiber can serve as another kind of laser gain medium between conventional bulk single crystal and glass fiber.The future work on pulling technique might focus on the mass production of rare earth single crystals with extreme size and with the size near that of devices.
