Abstract
Through investigations on the growth of the (100) face of potassium dihydrogen phosphate (KDP) crystal by ex situ atomic force microscopy (AFM) with different pH values at different supersaturations at 40°C, it was found that the growth of crystal was controlled by step flow at lower supersaturations, and the morphologies of steps were different under different growth conditions. In addition, at the higher supersaturations, 2D nucleation mechanism controlled the growth. When the supersaturations were lower, the dislocation mechanism controlled the growth of crystal, and when σ ⩾0.05, 2D nucleation mechanism played a dominant role in the growth of the (100) face for pH=4.2 and pH=2.5. However, for pH=5.0, the dislocation mechanism also dominated the growth of crystal when the supersaturations were lower, but when σ ⩾0.03, the crystal growth was controlled by 2D nucleation mechanism. Through investigations on the step flow of the (100) face of KDP crystal by in situ AFM with different pH values at lower supersaturations at 25°C, the velocities of normal growth of the (100) face were estimated at different growth conditions by in situ AFM. It was found that when the pH value was 5.0, the normal growth rate was the fastest at the same supersaturation compared to the other pH values and screw dislocation mechanism controlled the crystal growth. In addition, we found that with the reduction of the supersaturation of the solution, the density of steps also decreased, the width of steps became larger. Finally, a phenomenon which was the obvious anisotropic growth of steps in the step flow was observed by in situ AFM at σ = 0.025 at pH=5.0.
Similar content being viewed by others
References
Painsner J A, Boyes J D, Kuopen S A, et al. National ignition facility. Laser Focus World, 1994, 5: 75
Land T A, Martin T L, Potapenko S, et al. Recovery of surfaces from impurity poisoning during crystal growth. Nature, 1999, 399: 442–445
Land T A, DeYoreo J J, Lee J D. An in-situ AFM investigation of canavalin crystallization kinetics. Surf Sci, 1997, 384: 136–155
Land T A, DeYoreo J J, Martin T L, et al. Crysallog. Rep, 1999, 44: 655–666
Mariusz J K, Ranieri R. Ex situ investigation of surface topography of as-grown potassium dihydrogen phosphate crystals by atomic force microscopy. J Crystal Growth, 1996, 169: 548–556
Yang S F, Su G B, Tang J, et al. Surface topography of rapidly grown KH2PO4 crystals with additives: Ex situ investigation by atomic force microscopy. J Crystal Growth, 1999, 203: 425–433
Rashkovich L N, Chernevich T G, Gvozdev N V, et al. Steps wandering on the lysozyme and KDP crystals during growth in solution. Surf Sci, 2001, 492: L717–L722
De Yoreo J J, Land T A, Rashkovich L N, et al. The effect of dislocation cores on growth hillock vicinality and normal growth rates of KDP {101} surfaces. J Crystal Growth, 1997, 182: 442–460
Thomas T N, Land T A, Martin T, et al. AFM investigation of step kinetics and hillock morphology of the {100} face of KDP. J Crystal Growth, 2004, 260: 566–579
Rashkovich L N, Moldazhanova G T. Growth kinetics and morphology of potassium dihydrogen phosphate crystal faces in solutions of varying acidity. J Crystal Growth, 1995, 151: 145–152
Zhong D G, Teng B, Zhang G H, et al. Influence of pH value on dislocation structure of KDP crystal (in Chinese). J Synthetic Crystal, 2007, 36: 501–506
Cheng M, Li M W, Fu D, et al. KDP crystal growth in differing pH value (in Chinese). J Chongqing Univ, 2008, 31: 809–814
Cheng M, Li M W, Fu D, et al. Investigation on the nucleation kinetics of supersaturation solution of KDP with different pH values (in Chinese). J Funct Mater, 2009, 5: 853–857
Cheng M, Li M W, Cao Y C, et al. In situ AFM investigation of 2D nucleation on the (100) face of KDP. Crystal Res Tech, 2009, 44: 1215–1222
Yu J T, Li M W, Wang X D. {100} surface topography under 2D nucleation growth of ADP crystals: Ex situ investigation by atomic force microscopy (in Chinese). J Funct Mater, 2008, 39: 1034–1039
Min N B. Physical Foundation of Crystal Growth. Shanghai: Shanghai Scientific and Technologic Press, 1982. 309, 312, 394
Zhang X L. Chemistry of Coordination Compounds (in Chinese). Beijing: Higher Education Press, 1991. 59–92
Zaitseva N, Carman L. Rapid growth of KDP-type crystals. Prog Crystal Growth Charact, 2001, 43: 1–118
Sangwal K. Growth kinetics and surface morphology of crystals grown from solutions: Recent observations and their interpretations. Prog Crystal Growth Charact, 1998, 36: 163–248
Etsuro H, Tomoya O. Measurements of the concentration gradient around a growing crystal in an aqueous solution by moiré fringes. J Crystal Growth, 1981, 51: 113–118
Burton W K, Cabrera N, Frank F C. The growth of crystals and the epuilibrium strcture of their surfaces. Phil Trans Roy Soc, 1951, A: 243–299
Author information
Authors and Affiliations
Corresponding author
Additional information
This work was supported by the National Natural Science Foundation of China (Grant Nos. 50676113, 50976127).
Rights and permissions
About this article
Cite this article
Cheng, M., Li, M., Guo, J. et al. Ex situ and in situ AFM investigations on the growth of the (100) face of KDP with different pH values. Sci. China Technol. Sci. 53, 1554–1561 (2010). https://doi.org/10.1007/s11431-010-3162-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11431-010-3162-x