Atomic force microscopy studies on growth steps and 2D nuclei on the {100} faces of deuterated L-arginine phosphate crystals

Growth steps and 2D nuclei of the {100} faces of the deuterated L-arginine phosphate (DLAP) crystals have been studied using ex-situ atomic force microscopy (AFM). Straight steps along the b direction as well as meandered steps are detected. The bunched steps have wider terraces than the elementary ones, which are supposed to result from the slower growth rate of the former than the latter. Many 2D nuclei exist on the step terraces and edges acting as the growth sources. Occasionally, 2D islands generated by 2D nuclei could also be observed. In conclusion, the crystal grows by layer growth mechanism.