In order to grow a large twin-free ZnSe single crystal, a closed double-crucible was used to prevent any deviation from the stoichiometric compositions of the melt during Bridgman growth, and the optimum growth conditions were determined. They contain a special temperature program, an over-heating temperature of 76K from the melting point of 1797K, and the temperature gradient at the growth interface of 30K/cm and a growth rate of 3.6mm/h. Under these growth conditions, twin-free high-quality ZnSe single crystals were successfully grown by using a polycrystalline seed. Chemical etching of the cleaved (110) plane showed that the average value of the etch-pit density was about 2 x 105/cm2. The rocking curves of 4-crystal X-ray diffraction have shown the 19 arcsec in full-width at half-maximum. The photoluminescence spectra at 4.2K have shown the resolved intensive free exciton, bound exciton emission lines and the weak DAP emission bands. The full-width at half-maximum of I1d emission was less than 0.0005eV. However, the deep-level emission bands were hardly observed. Above all, the results suggested that the ZnSe single crystals grown by the present method were of a very high quality.

Bridgman Growth of Twin-Free ZnSe Single Crystals. J.F.Wang, A.Omino, M.Isshiki: Materials Science and Engineering B, 2001, 83[1-3], 185-91