Professor Y. K. Rao
Single crystals of indium sesquioxide were grown by Jόzefowicz and Piekarczyk  in a closed
quartz ampoule using Cl2(g) transport reagent. The sealed ampoule reactor was positioned in a twozone
furnace with a predetermined temperature-gradient (TS → Td). The gas-phase generated by the
interaction between Cl2(g) and the oxide-fines was composed of species InCl, InCl2, InCl3, In2Cl6, Cl2,
Cl, ClO, In2Cl4, In2O and O2. Mass-transfer of gaseous species takes place by diffusion, Stefan flow
and convection. The present work determines, by computation, the growth-rate of the In2O3-crystals ;
it consists of solving the steady-state (virtual equilibrium) in the closed reactor using the equilibrium
constants for the gas-solid reactions (at TS and Td), together with the element-atom-balances for Cl, In
and O, the uniform total pressure and conformity with respect to the diffusion-flux constraints. The
large total pressure (777.953 kPa) in the reactor results in a substantial role for the convective masstransport.
It will be noted that heat treatment of the sealed ampoule reactor under a reverse temperature-
gradient ahead of the normal growth-schedule appears to diminish the rate of crystal growth.