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, Jcrit and ΔTcrit, 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 Jexp 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.