In x Ga 1−x Sb bulk crystals are to be grown using a GaSb(seed)/InSb/GaSb(feed) sandwich-structured sample onboard the International Space Station (ISS). The InGaSb crystals will be grown on top of GaSb seed single crystals with different orientations viz., (111)A, (111)B, (110), (100) in order to examine and understand the growth kinetics of the crystals. In the present work, a numerical model of the crystal growth system has been developed to investigate the interface kinetics effects on the growth process by taking kinetics coefficient into account. The proposed numerical model was applied to evaluate the effect of crystal orientation on growth rate. Simulation results showed that the kinetics coefficient, whose value depends on crystal orientation, affected the growth rate of InGaSb crystal and the dissolution rate of GaSb feed crystal in the sandwich system.
Nomenclaturevector in the vertical direction f interface position (m) g gravity acceleration (m · s −2 ) La latent heat (J · kg −1 ) m slope of the interface n unit vector normal to the interface p pressure (Pa) T temperature (K) u fluid velocity component in the horizontal direction (m · s −1 ) t time (s) v fluid velocity vector (m · s −1 ) v fluid velocity component in the vertical direction (m · s −1 ) x horizontal direction coordinate (m) y vertical direction coordinate (m) y + dimensionless wall distance (-) G acceleration normalised by gravity of Earth (m · s −2 )Greek symbols α thermal diffusivity (m 2 · s −1 ) β kinetics coefficient (m · s −1 ) β(0) kinetics coefficient at the unperturbed interface (m · s −1 ) β st kinetics coefficient of steps (m · s −1 ) β C solutal expansion coefficient (-) Microgravity Sci. Technol. β T thermal expansion coefficient (K −1 ) λ thermal conductivity (W · m −1 · K −1 ) μ viscosity (kg · m −1 · s −1 ) ρ density (kg · m −3 ) ν kinematic viscosity (m 2 · s −1 ) C concentration difference (-)