Surface morphology and defect formation of the {100} face of ZnCd(SCN)4 crystals investigated by AFM

Surface morphology and defect formation of the prismatic {100} face of ZCTC crystals were investigated by atomic force microscopy ( AFM). Both screw-dislocation-controlled growth and two- dimensional nucleation growth occur on the face at a supersaturation of 0.03. Steps advance with strong kinetic anisotropy along the b- axis direction, probably because different parts of the ZCTC molecules are exposed along different crystallographic directions. By comparing heights of elementary steps with the structure of the ZCTC crystal, it is deduced that the growth of ZCTC crystals occurs mostly by direct incorporation of monomers or dimers of ZCTC molecules into the crystal. Defects of hollow channels, negative crystals and cracks that are oriented preferentially along the direction of the b or c axis were observed. The formation of the defects is mainly related to the growth mechanism and structural features of the ZCTC crystal.