THE OPTIMAL TEMPERATURE PROFILE IN CRYSTAL-GROWTH FROM THE VAPOR

An attempt at an analytical explanation of the role of the axial tempe rature profile in a tubular furnace in the growth of crystals from the vapour phase is reported. Three possible profile shapes are compared and discussed. The optimal profile is found to be characterized by an isothermal plateau at the location of the source material and a temper ature hump between the source material and crystal. This profile was u sed for the growth of good quality ternary and quaternary ZnSe compoun ds with transition metals (ZnMnSe, ZnFeSe, ZnNiSe, ZnFeSSe, ZnSeS) by chemical vapour transport. The quality of the crystals was confirmed b y double crystal X-ray diffraction, which showed the full width half m aximum (FWHM) of the rocking curves to be as low as 12 arcsec on the n atural faces of the crystals.