Theoretical gravity studies on roles of convection in crystal growth of Hg2Cl2-Xe by physical vapor transport under normal and high gravity environments
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Particular interest in the role of convection in vapor crystal growth has arisen since some single crystals under high gravity acceleration of 10g0 appear considerably larger than those under normal gravity acceleration (1g0). For both ΔT = 60 K and 90 K, the mass flux increases by a factor of 3 with increasing the gravity acceleration from 1g0 up to 10g0. On the other hand, for ΔT = 30 K, the flux is increased by a factor of 1.36 for the range of 1g0 ≤ g ≤ 10g0. The maximum growth rates for 1g0, 4g0, 10g0 appear approximately in the neighborhood of y = 0.5, and the growth rates shows asymmetrical patterns, which indicate the occurrence of either one single or more than one convective cell. The maximum growth rate for 10g0 is nearly greater than that for 1g0 by a factor of 2.0 at PB = 20 Torr. For three different gravity levels of 1g0, 4g0 and 10g0, the maximum growth rates are greater than the minimum rates by a factor of nearly 3.0, based on PB = 20 Torr. The mass flux increases with increasing the gravity acceleration, for 1g0 ≤gy≤ 10g0, and decreases with increasing the partial pressure of component B, xenon (Xe), PB. The |U|max is directly proportional to the gravity acceleration for 20 Torr ≤ PB≤ 300 Torr. As the partial pressure of PB (Torr) decreases from 300 Torr to 20 Torr, the slopes of the |U|maxs versus the gravity accelerations increase from 0.1 sec to 0.17 sec. The mass flux of Hg2Cl2 is exponentially decayed with increasing the partial pressure of component B, PB (Torr) from 20 Torr up to 300 Torr .
Abstract
Particular interest in the role of convection in vapor crystal growth has arisen since some single crystals under high gravity acceleration of 10g0 appear considerably larger than those under normal gravity acceleration (1g0). For both ΔT = 60 K and 90 K, the mass flux increases by a factor of 3 with increasing the gravity acceleration from 1g0 up to 10g0. On the other hand, for ΔT = 30 K, the flux is increased by a factor of 1.36 for the range of 1g0 ≤ g ≤ 10g0. The maximum growth rates for 1g0, 4g0, 10g0 appear approximately in the neighborhood of y = 0.5, and the growth rates shows asymmetrical patterns, which indicate the occurrence of either one single or more than one convective cell. The maximum growth rate for 10g0 is nearly greater than that for 1g0 by a factor of 2.0 at PB = 20 Torr. For three different gravity levels of 1g0, 4g0 and 10g0, the maximum growth rates are greater than the minimum rates by a factor of nearly 3.0, based on PB = 20 Torr. The mass flux increases with increasing the gravity acceleration, for 1g0 ≤gy≤ 10g0, and decreases with increasing the partial pressure of component B, xenon (Xe), PB. The |U|max is directly proportional to the gravity acceleration for 20 Torr ≤ PB≤ 300 Torr. As the partial pressure of PB (Torr) decreases from 300 Torr to 20 Torr, the slopes of the |U|maxs versus the gravity accelerations increase from 0.1 sec to 0.17 sec. The mass flux of Hg2Cl2 is exponentially decayed with increasing the partial pressure of component B, PB (Torr) from 20 Torr up to 300 Torr .
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