Investigation of growth mechanisms of TSS-grown KLu(WO4)2 crystals by atomic force microscopy

Growth mechanisms on the {1 1 0} and {3 1 0} faces of KLu(WO4)2 crystals for the case of top-seeded solution growth technique have been investigated using ex situ atomic force microscopy (AFM). Both 2D nuclei and spiral hillocks are imaged simultaneously on the {1 1 0} surfaces. A special dislocation sources structure with the Burgers vectors perpendicular to the {1 1 0} crystal face of b = 8 are discussed. The 2D nuclei with elementary-step height are distributed in the direction of the strong PBC [1 0 1], indicative of anisotropic surface diffusion or step edge energy. Straight step trains are observed on the {3 1 0} surfaces of KLuW and they move towards to [0 0 1] directions. It was confirmed that the growth proceeds by both screw dislocation sources and 2D nucleus on the {1 1 0} surfaces and by simple flow of steps on {3 1 0} surfaces.