Global Simulation Of CdZnTe By Detached Solidification Under Cusp Magnetic Field

The traditional methods about crystal growth from melt are the Czochralskimethod and the Bridgman method. Both the advantages and defects exist in these twocrystal growth methods. The detached solidification technique combines theirsuperiorities, so grows higher quality crystals. However, it still belongs to the methodsof crystal growth from melt, the chemical and physical properties of the crystal can beaffected by the melt flow in the crucible. The melt flow can be controlled by applying ofa magnetic field. CdZnTe is a semiconductor material which has broad applicationprospects. It is often used in medical imaging and diagnosis, environment monitoring,industrial measurement and astrophysics, et al. Until now, most of the researchesfocused on the experiments, and it is still few for the theory work of the detachedsolidification process for CdZnTe. Therefore this research has important theoreticalvalue and engineering meaning.In order to clarify the effects of parameters on the growth quality of CdZnTecrystal in a cusp magnetic field, the global simulation analyses for heat and momentumtransfers in a crucible was carried out using a finite-element method. The effects of thedifferent magnetic field structure, magnetic intensity, gravity level, temperature gradientand crucible radius on the CdZnTe crystal growth were analyzed.The numerical simulation results show that：(1) when the center of cusp magneticfield positioned10mm above the interface of melt-crystal, magnetic field concentratedin the upper and lower areas of the melt and near the wall. Buoyancy convection andthermocapillary convection were suppressed by the magnetic that lead to weak thestrength of the flow in the melt.(2) The inhibition of the flow in melt by Lorentz wasgradually enhanced with the increase of magnetic field. When magnetic field intensitywas2.0T, buoyancy convection and thermocapillary convection were well suppressedwhich favors the crystal steady growth.(3) As the increases in the gravity level, themaximum stream function was increasing and the melt flow was strengthened gradually.The melt flow was suppressed by applying a cusp magnetic field.(4) As the increases inthe temperature gradient in the wall, the crystal-melt interface began to move up whichmade the area of melt become smaller. In order to control the flow, a cusp magneticfield was applied which can ensure crystal growth rate, at the same time, the melt flowin the melt can be controlled in a certain range.(5) With the increase of crucible radius, the maximum stream function was increasing and the melt flow was strengthenedgradually. We found that the inhibition of magnetic field on the large size of the cruciblewas more effective.