Study on rapid growth of 98% deuterated potassium dihydrogen phosphate (DKDP) crystals

•We grow tetragonal DKDP crystals rapidly under higher temperatures up to 51.0 °C.•We study the surface morphologies of tetragonal and monoclinic DKDP crystals.•We investigate the growth habits of tetragonal and monoclinic DKDP crystals.

Tetragonal 98% deuterated potassium dihydrogen phosphate (DKDP) crystals were grown rapidly from synthetic DKDP solution with higher deuterium concentration by using point-seeds technique. Crystallization was carried out under high supersaturation at different temperatures ranging from 38.3 °C to 51.0 °C. It is found that the metastable region of DKDP solution is non-specific and DKDP crystal can be grown from high starting temperature beyond the traditional metastable region. For comparison, monoclinic DKDP crystals were grown from the same solution. Surface morphologies of tetragonal and monoclinic DKDP crystals were investigated by AFM technique. The different growth habits between tetragonal and monoclinic DKDP crystals were analyzed according to their crystal structures with bond valence model.