Mass flux of ZnSe-N-H-Cl chemical vapor transport (CVT) system

The vapor transport properties in ZnSe-N-H-Cl CVT systems are interpreted based on the one-dimensional diffusion-limited model. The growth rate J is calculated to be 3.5-3.7×10^-9 mol cm^-2 s^-1 at the temperature difference ΔT of 5 K between the source and the growth ends in the systems of ZnSe-NH₄Cl, ZnSe-NH₄Cl+Se and ZnSe-ZnCl₂·2NH₄Cl (AZC-II)+Se. The values related to the critical stability parameters of surface, J_crit and ΔT_crit, are about 2.6×10^-9 mol cm^-2 s^-1 and 3.5 K, respectively. J is not dependent on the amount of NH₄Cl among the concentration range from 0.5 to 5.0 mg mL^-1. The deviation from stoichiometry of the source material hardly affects on J when AZC-II and Se were added. The experimental investigations of transport rate are carried out using the seeded and un-seeded ampoules with various tip angles. The experimental growth rate J_exp and its critical values well agree with the calculated results. A critical temperature difference up to 5-7 K is obtained in the vertical manner growth.