TY - JOUR
T1 - The prospects for traveling magnetic fields to affect interface shape in the vertical gradient freeze growth of cadmium zinc telluride
AU - Yeckel, Andrew
AU - Derby, Jeffrey J.
PY - 2013/1/1
Y1 - 2013/1/1
N2 - The influence of a traveling magnetic field (TMF) on vertical gradient freeze (VGF) growth of cadmium zinc telluride (CZT) is studied using a coupled model of magnetic induction, fluid dynamics, and heat transfer. Simulations are performed to determine the influences of current, phase shift, and frequency on melt flow and growth interface shape. A downward traveling electromagnetic wave drives flow downward at the wall, which tends to flatten the interface, whereas an upward traveling wave has the opposite effect. An optimum phase shift that maximizes Lorentz force is found to depend only on system geometry. Large currents (∼ 300 A) and high frequencies (∼ 500 Hz) make a significant impact on interface shape in the absence of thermal buoyancy, but are ineffectual under realistic conditions in a 4 in.-diameter ampoule, for which buoyancy dominates Lorentz force throughout the melt. The results indicate that interface shape in this CZT growth system is strongly governed by furnace heat transfer and is difficult to modify by TMF-driven forced convection.
AB - The influence of a traveling magnetic field (TMF) on vertical gradient freeze (VGF) growth of cadmium zinc telluride (CZT) is studied using a coupled model of magnetic induction, fluid dynamics, and heat transfer. Simulations are performed to determine the influences of current, phase shift, and frequency on melt flow and growth interface shape. A downward traveling electromagnetic wave drives flow downward at the wall, which tends to flatten the interface, whereas an upward traveling wave has the opposite effect. An optimum phase shift that maximizes Lorentz force is found to depend only on system geometry. Large currents (∼ 300 A) and high frequencies (∼ 500 Hz) make a significant impact on interface shape in the absence of thermal buoyancy, but are ineffectual under realistic conditions in a 4 in.-diameter ampoule, for which buoyancy dominates Lorentz force throughout the melt. The results indicate that interface shape in this CZT growth system is strongly governed by furnace heat transfer and is difficult to modify by TMF-driven forced convection.
KW - A1. Computer simulation
KW - A1. Convection
KW - A1. Heat transfer
KW - A1. Magnetic fields
KW - A2. Gradient freeze technique
KW - B2. Semiconducting II-VI materials
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U2 - 10.1016/j.jcrysgro.2012.11.029
DO - 10.1016/j.jcrysgro.2012.11.029
M3 - Article
AN - SCOPUS:84888335450
VL - 364
SP - 133
EP - 144
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
SN - 0022-0248
ER -