• Journal of the Korean Ceramic Society
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• v.22 no.2
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• pp.51-57
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• 1985

Silicon single crystals were grown bynon-seeded vertical Brdgmen-Stockbarger technique. Optimum growth rate appeared 5mm/hr in the system. It was identified that the preferential orientation using by the optical microscope resulted in <100> direction.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.239-241
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• 1996

The energy gap of GaSe:$Er^{3+}$(5mol%) single crystals grown by the Bridgman technique displaced a direct energy gap at 1.79 eV and an indirect energy gap at 1.62 eV at $300^{\circ}K$ with the addition of Erbium. Also, an impurity optical absorption peak was found to have occurred at $6505\;cm^{-1}$. The peak identified the origin of the electronic transitions between the energy levels of $Er^{3+}$ ions when the addition of dopant.

• Journal of Mechanical Science and Technology
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• v.15 no.8
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• pp.1188-1195
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• 2001

A numerical analysis has been carried out to investigate the influences of thermosolutal convection on the heat and mass transfer and solute segregation in crystals grown by the vertical Bridgman technique. The governing equations are solved by a finite-volume method using the power law scheme and the SIMPLE algorithm in which body-fitted coordinate system has been used. A primary convective cell driven by thermal gradients forms in the bulk of the domain, while a secondary convective cell driven by solutal gradients forms near interface. As the solutal Rayleigh number increases, secondary cell becomes to be stronger and has a great influence on the radial concentration along the interface.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.3
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• pp.771-783
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• 1995

A simplified model for the so-called ACRT(accelerated crucible rotation technique) Bridgman crystal growth was considered in order to investigate the principal effects of the periodic variation of angular velocity. Numerical solutions were obtained for Ro=0.5, Ra=4.236*10$_{6}$ and E=2.176*10$^{-3}$ . The effects of spin-up process combined with natural convection was investigated as a preliminary study. The spin-up time scale for the present problem was a little larger than that observed for homogeneous spin-up problems. Numerical results reveal that over a time scale of (H$^{2}$/.nu..omega.$_{f}$)$^{1}$2/ the forced convection due to the formation of Ekman layer predominates. When the state of rigid body rotation is attained, natural convection due to buoyancy emerges as the main driving force and them the steady-state is approached asymptotically. Based on our preliminary results with simple spin-up, several fundamental features associated with variation of rotation speed are successfully identified. When a periodic variation of angular velocity was imposed, the system response was also periodic. Due to effect of mixing, the heat transfer was enlarged. From the analysis of time-averaged Nusselt number along the bottom surface the effect of a periodic variation of angular velocity on the interface location could be indirectly identified.d.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.8
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• pp.629-633
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• 2001

Electrical properties of the $\alpha$-In$_2$Se$_3$ single crystals grown by use of the Bridgman technique were examined in the transition temperature range between $\alpha$-phase and $\beta$-phase. $\alpha$-In$_2$Se$_3$ single crystal has ' the rhombohedral structure and lattice constants are a=4.025 $\AA$, c=28.771 $\AA$ in c-axis. The transition temperatures of the stoichiometric $\alpha$-In$_2$Se$_3$ single crystal is 198.8$^{\circ}C$ according to the specimens. The temperature of $\alpha$longrightarrow$\beta$ phase transition decreased but the temperature of $\beta$longrightarrow$\alpha$ phase transition increased as the number of heating-cooling cycle increased.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4215-4219
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• 2022

The Cd_0.95Mn_0.05Te_0.98Se_0.02 (CMTS) ingot was grown by the vertical Bridgman technique at low pressure. All wafers showed high resistivity, which suggests potential as a room-temperature semiconductor detector. The resistivity of the CMTS planar detector was 1.47 × 10¹⁰ Ω·cm and mobility lifetime product of electrons was 1.29 × 10^-3 cm²/V. The spectroscopic property with Am-241 and Co-57 was evaluated. The energy resolution about 59.5 keV gamma-ray of Am-241 was 11% and the photo-peak of 122 keV gamma-ray from Co-57 was clearly distinguished. The result shows the first detector-grade CMTS in the world and proves CMTS's potential as a radiation detector operating at room temperature.

• Journal of the Korean Magnetics Society
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• v.16 no.3
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• pp.178-181
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• 2006

We have investigated the Mn concentration-dependent structural, optical, magnetic properties in IV-VI diluted magnetic semiconductor $Si_{1-x}Mn_xTe_{1.5} $ crystals prepared by the vertical Bridgman technique. X-ray studies showed the single crystalline hexagonal crystal structure. From the optical absorption measurements energy band gap were found to decreases with increasing x and temperature. From the magnetization measurements the samples had ferromagnetic ordering with Curie temperature $T_C$ about 80 K. With increasing Mn concentration, the average magnetic moments per Mn atom determined from the saturated magnetization increased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.278-281
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• 2003

The p-CIn2Te4 single crystal was grown in the three-stage vertical electric furnace by using Bridgman method. The quality of the grown crystal has been investigated by the x-ray diffraction and the photoluminescence measurements. From the photoluminescence spectra of the as-grown CdIn2Te4 crystal and the various heat-treated crystals, the (Do, X) emission was found to be the dominant intensity in the photoluminescence spectrum of the CdIn2Te4:Cd, while the (Ao, X) emission completely disappeared in the CdIn2Te4:Cd. However, the (Ao, X) emission in the photoluminescence spectrum of the CdIn2Te4:Te was the dominant intensity like an as-grown CdIn2Te4 crystal. These results indicated that the (Do, X) is associated with VTe acted as donor and that the (Ao, X) emission is related to VCd acted as acceptor, respectively. The p-CdIn2Te4 crystal was found to be obviously converted into the n-type after annealing in the Cd atmosphere. The origin of (Do, Ao) emission and its TO phonon replicas is related to the interaction between donors such as VTe or Cdint, and accepters such as VCd or Teint. Also, the In in the CdIn2Te4 was confirmed not to form the native defects because it existed in the stable form of bonds.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.6
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• pp.535-541
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• 1999

Low-dislocation-density large-diameter GaAs single crystals with low-residual-strain have been strongly required. We have developed dislocation-free 3-inch Si doped GaAs crystals for photonic devices, and low-dislocation-density low-residual-strain 4-inch to 6-inch semi-insulating GaAs crystals for electronic devices by Vertical Bridgman(VB) technique. We confirmed that VB substrates with low-residual-strain have higher resistance against slip-line generation during MBE process. VB-GaAs single crystals show uniform radial profile of resistivity reflecting to the flat solid-liquid interface during the crystal growth. Uniformity of micro-resistivity of VB-GaAs substrate is much better than of the LEC-GaAs substrate, which is due to the low-dislocation-density of VB-GaAs single crystals.

• Journal of Sensor Science and Technology
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• v.15 no.6
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• pp.379-385
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• 2006

Single crystal of p-$CdIn_{2}Te_{4}$ was grown in a three-stage vertical electric furnace by using Bridgman method. The quality of the grown crystal has been investigated by x-ray diffraction and photoluminescence measurements. From the photoluminescence spectra of the as-grown $CdIn_{2}Te_{4}$ crystal and the various heat-treated crystals, the ($D^{o}$, X) emission was found to be the dominant intensity in the photoluminescence spectrum of the $CdIn_{2}Te_{4}$:Cd, while the ($A^{o}$, X) emission completely disappeared in the $CdIn_{2}Te_{4}$:Cd. However, the ($A^{o}$, X) emission in the photoluminescence spectrum of the $CdIn_{2}Te_{4}$:Te was the dominant intensity like in the as-grown $CdIn_{2}Te_{4}$ crystal. These results indicated that the ($D^{o}$, X) is associated with $V_{Te}$ which acted as donor and that the ($A^{o}$, X) emission is related to $V_{Cd}$ which acted as acceptor, respectively. The p-$CdIn_{2}Te_{4}$ crystal was obviously found to be converted into n-type after annealing in Cd atmosphere. The origin of ($D^{o},{\;}A^{o}$) emission and its to phonon replicas is related to the interaction between donors such as $V_{Te}$ or $Cd_{int}$, and acceptors such as $V_{Cd}$ or $Te_{int}$. Also, the In in the $CdIn_{2}Te_{4}$ was confirmed not to form the native defects because it existed in a stable bonding form.