Surface defects and mechanical hardness of rapidly grown DAST crystals

DAST crystals were grown by the two-zone growth technique and the crystal surfaces were analyzed with help of optical and scanning electron microscopic results. Owing to a high supersaturation in the growth zone, growth striations were observed on the {0 0 1} smooth surfaces (vicinal), while macrosteps were observed on the {0 0 1̄} rough surfaces of the grown crystals. Hillocks occurred on the F-surface, because new layers nucleated before the lateral growth of the deeper layers were completed. The microhardness of the grown crystals was measured on the (0 0 1) and (1 1 0) faces under different loads.