Stabilization of Melt Convection of Lithium Niobate Using Accelerated Crucible Rotation Technique

2003 ◽  
Vol 150 (5) ◽  
pp. J17 ◽  
Author(s):  
Koichi Kakimoto ◽  
Hiroyuki Konishi ◽  
Akimasa Tashiro ◽  
Yoshio Hashimoto ◽  
Hideo Ishii ◽  
...  
Keyword(s):  
Lithium Niobate ◽  
Rotation Technique ◽  
Melt Convection ◽  
Crucible Rotation

Influence of melt convection on microstructure evolution of Nd-Fe-B alloys using a forced crucible rotation technique

2006 ◽  
Vol 3 (9) ◽  
pp. 3277-3280
Author(s):  
K. Biswas ◽  
R. Hermann ◽  
O. Filip ◽  
J. Acker ◽  
G. Gerbeth ◽  
...  
Keyword(s):  
Microstructure Evolution ◽  
Rotation Technique ◽  
Melt Convection ◽  
Crucible Rotation

Turbulent Convection in a Czochralski Silicon Melt

1999 ◽  
Vol 121 (4) ◽  
pp. 1027-1041 ◽  
Author(s):  
T. Zhang ◽  
F. Ladeinde ◽  
V. Prasad
Keyword(s):  
Growth Conditions ◽  
Crucible Wall ◽  
Combined Effects ◽  
Dynamic Adjustment ◽  
Volume Calculation ◽  
Rotation Rates ◽  
Growth System ◽  
Melt Convection ◽  
The Individual ◽  
Crucible Rotation

The individual and combined effects of buoyancy, crystal rotation, and crucible rotation are reported in this paper for axisymmetrically averaged melt convection in a large Czochralski crystal growth system for silicon. These body force effects are characterized by the respective parameters of Grashof number, Gr, rotational Reynolds number, Rer, and the Marangoni number, Ma. The range investigated consists of 108 ≤ Gr ≤ 1010, 103 ≤ Re ≤ 3 × 104, and 103 ≤ Ma ≤ 104, which is appropriate for the real Czochralski system. The studies are based on a multizone, adaptive, finite volume calculation. Validations of the numerical procedures are presented, including a grid convergence study. The effects of buoyancy and rotation on melt convection are discussed in detail. When the crystal and crucible both rotate at the same speed, but in opposite directions, without buoyancy, the effect of the crucible rotation is stronger. The rotation induces turbulence, contrary to what the literature suggests. For the combined effects, the intensity of turbulence and the average Nusselt number at the crucible wall are largest when buoyancy is slightly dominant over rotation. High rotation rates generate temperature oscillations in the presence of high Grashof numbers. Because of the consequence of oscillation for crystal quality, a dynamic adjustment of the rotation rate might be necessary in order to obtain desirable growth conditions.

Crystal growth of CuInSe2 by the Bridgman method

1989 ◽  
Vol 67 (4) ◽  
pp. 294-297 ◽  
Author(s):  
W. S. Weng ◽  
L. S. Yip ◽  
I. Shih ◽  
C. H. Champness
Keyword(s):  
Crystal Growth ◽  
Room Temperature ◽  
Amorphous Layer ◽  
Bridgman Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vertical Bridgman ◽  
Hall Effect Measurements ◽  
Rotation Technique ◽  
Crucible Rotation

Single crystals of CuInSe2 have been fabricated by the vertical Bridgman method. A conventional Czochralski crystal-pulling system was adapted for this purpose. An accelerated crucible-rotation technique was employed for a better mixing of the melt during the growth. Void- and crack-free crystal grains with an area as large as 50 mm2 and a thickness of more than 5 mm could be selectively cut from the ingots. From room-temperature Hall-effect measurements, mobility values as large as 73 cm2 ∙ V−1 ∙ s−1 were obtained for the present samples. X-ray diffraction studies suggested that abrasive polishing might create an amorphous layer on the surface of the CuInSe2 crystals.

Improvements in Thallium Bromoiodide Photodetectors for Scintillation Spectrometers

1993 ◽  
Vol 302 ◽  
Author(s):  
J.G. Zhang ◽  
L. Cirignano ◽  
K. Daley ◽  
M.R. Squillante
Keyword(s):  
High Performance ◽  
Carrier Mobility ◽  
High Dielectric Constant ◽  
Signal To Noise Ratio ◽  
Charge Carrier Mobility ◽  
Large Area ◽  
Semiconductor System ◽  
Rotation Technique ◽  
High Dielectric ◽  
Crucible Rotation

ABSTRACTThallium bromoiodide, a tuneable band gap semiconductor system, was investigated as a photodetector for scintillation spectrometers. Extensive zone refining of starting materials, based on numerical simulations, considerably enhanced the electrical resistivity to 1011 Ωcm. In addition, accelerated crucible rotation technique (ACRT) crystal growth and after-growth annealing have improved the charge carrier mobility-lifetime product. However, a relatively low signal-to-noise ratio due to a high dielectric constant and relatively low quantum efficiency continues to be an obstacle to achieving high performance, large area T1BrxI1−xphotodetectors.

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