Influence of thermo-physical properties on solutal convection by physical vapor transport of Hg2Cl2-N2 system: Part I - solutal convection

Abstract

For typical governing dimensionless parameters of Ar = 5, Pr = 1.16, Le = 0.14, Pe = 3.57, Cv = 1.02, <TEX>$Gr_s=2.65{\times}10^6$</TEX>, the effects of thermo physical properties such as a molecular weight, a binary diffusivity coefficient, a partial pressure of component B on solutally buoyancy-driven convection (solutal Grashof number <TEX>$Gr_s=2.65{\times}10^6$</TEX>) are theoretically investigated for further understanding and insight into an essence of solutal convection occurring in the vapor phase during the physical vapor transport of a <TEX>$Hg_2Cl_2-N_2$</TEX> system. The solutally buoyancy-driven convection is significantly affected by any significant disparity in the molecular weight of the crystal components and the impurity gas of nitrogen. The solutal convection in a vertical orientation is found to be more suppressed than a tenth reduction of gravitational accelerations in a horizontal orientation. For crystal growth parameters under consideration, the greater uniformity in the growth rate is obtained for either solutal convection mode in a vertical orientation or thermal convection mode in horizontal geometry. The growth rate is also found to be first order exponentially decayed for <TEX>$10{\leq}P_B{\leq}200$</TEX> Torr.