Imperfect oriented attachment: Dislocation generation in defect-free nanocrystals

Science

Volumn 281, Issue 5379, 1998, Pages 969-971

  Penn, R Lee ^a   Banfield, Jillian F ^a,b  

^a UNIVERSITY OF WISCONSIN MADISON   (United States)

^b UNIVERSITY OF TOKYO   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

NANOPARTICLE;

ARTICLE; CRYSTAL STRUCTURE; CRYSTALLIZATION; CRYSTALLOGRAPHY; PRIORITY JOURNAL; SURFACE PROPERTY;

EID: 0032516657     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.281.5379.969     Document Type: Article

References (29)

1. The two most commonly noted mechanisms of crystal growth are spiral growth around a dislocation and surface nucleation followed by two-dimensional growth. Both mechanisms involve the addition of atoms to reactive surface sites from solution, vapor, or melt. W. K. Burton, N. Cabrera, F. C. Frank, Nature 163, 398 (1949); L. J. Griffin, Philos. Mag. 41, 196 (1950); W. K. Burton, N. Cabrera, F. C. Frank, Philos. Trans R. Soc. London A 243, 299 (1951); J. Friedel, Dislocations (Pergamon, New York, 1964). M. F. Hochella, Mineral-Water Interface Geochemistry, vol. 23 of Reviews in Mineralogy, M. F. Hochella and A. F. White, Eds. (Mineralogical Society of America, Washington, DC, 1990), pp. 87-132.
2. The two most commonly noted mechanisms of crystal growth are spiral growth around a dislocation and surface nucleation followed by two-dimensional growth. Both mechanisms involve the addition of atoms to reactive surface sites from solution, vapor, or melt. W. K. Burton, N. Cabrera, F. C. Frank, Nature 163, 398 (1949); L. J. Griffin, Philos. Mag. 41, 196 (1950); W. K. Burton, N. Cabrera, F. C. Frank, Philos. Trans R. Soc. London A 243, 299 (1951); J. Friedel, Dislocations (Pergamon, New York, 1964). M. F. Hochella, Mineral-Water Interface Geochemistry, vol. 23 of Reviews in Mineralogy, M. F. Hochella and A. F. White, Eds. (Mineralogical Society of America, Washington, DC, 1990), pp. 87-132.
3. The two most commonly noted mechanisms of crystal growth are spiral growth around a dislocation and surface nucleation followed by two-dimensional growth. Both mechanisms involve the addition of atoms to reactive surface sites from solution, vapor, or melt. W. K. Burton, N. Cabrera, F. C. Frank, Nature 163, 398 (1949); L. J. Griffin, Philos. Mag. 41, 196 (1950); W. K. Burton, N. Cabrera, F. C. Frank, Philos. Trans R. Soc. London A 243, 299 (1951); J. Friedel, Dislocations (Pergamon, New York, 1964). M. F. Hochella, Mineral-Water Interface Geochemistry, vol. 23 of Reviews in Mineralogy, M. F. Hochella and A. F. White, Eds. (Mineralogical Society of America, Washington, DC, 1990), pp. 87-132.
4. The two most commonly noted mechanisms of crystal growth are spiral growth around a dislocation and surface nucleation followed by two-dimensional growth. Both mechanisms involve the addition of atoms to reactive surface sites from solution, vapor, or melt. W. K. Burton, N. Cabrera, F. C. Frank, Nature 163, 398 (1949); L. J. Griffin, Philos. Mag. 41, 196 (1950); W. K. Burton, N. Cabrera, F. C. Frank, Philos. Trans R. Soc. London A 243, 299 (1951); J. Friedel, Dislocations (Pergamon, New York, 1964). M. F. Hochella, Mineral-Water Interface Geochemistry, vol. 23 of Reviews in Mineralogy, M. F. Hochella and A. F. White, Eds. (Mineralogical Society of America, Washington, DC, 1990), pp. 87-132.
5. The two most commonly noted mechanisms of crystal growth are spiral growth around a dislocation and surface nucleation followed by two-dimensional growth. Both mechanisms involve the addition of atoms to reactive surface sites from solution, vapor, or melt. W. K. Burton, N. Cabrera, F. C. Frank, Nature 163, 398 (1949); L. J. Griffin, Philos. Mag. 41, 196 (1950); W. K. Burton, N. Cabrera, F. C. Frank, Philos. Trans R. Soc. London A 243, 299 (1951); J. Friedel, Dislocations (Pergamon, New York, 1964). M. F. Hochella, Mineral-Water Interface Geochemistry, vol. 23 of Reviews in Mineralogy, M. F. Hochella and A. F. White, Eds. (Mineralogical Society of America, Washington, DC, 1990), pp. 87-132.
6. R. J. Kirkpatrick, Kinetics of Geochemical Processes, vol. 8 of Reviews in Mineralogy, A. S. Lasaga and R. J. Kirkpatrick Eds. (Mineralogical Society of America, Washington, DC, 1981), pp. 321-398.
7. A. Lasaga, Kinetics of Geochemical Processes, vol. 8 of Reviews in Mineralogy, A. S. Lasaga and R. J. Kirkpatrick Eds. (Mineralogical Society of America, Washington, DC, 1981), pp. 261-320.
8. A. P. Alivisatos, Ber. Bunsenges Phys. Chem. 101, 1573 (1997). One attempt to explain the absence of defects in nanocrystals is to estimate the equilibrium distance between two dislocations in the case of dislocation pileup by relating the repulsive force between two dislocations to an externally applied force (17). This model predicts that dislocations are unstable within crystallites of dimensions smaller than such a calculated distance. If we use published values for the shear modulus (18), a Burgers vector of 0.4 nm, an estimated Poisson's ratio, and hardness, the calculated minimum distance between dislocations in titania (anatase) is between 7 and 8 nm. The minimum separation is predicted to scale with the magnitude of the Burgers vector. This prediction is supported by HRTEM examination of the nanocrystalline titania used in this study, which revealed the as-synthesized particles (which are 5 to 6 nm in diameter) to be dislocation free (19).
9. Incorporation of impurities in a growing crystal and shear stress [in nanocrystalline aggregates (8)] can introduce dislocations. However, in many cases, explanations involving impurity adsorption and shear are unsatisfactory, and alternative mechanisms for dislocation formation are required.
10. R. L. Penn and J. F. Banfield, in preparation.
11. J. F. Banfield and R. J. Hamers, Geomicrobiology: Interactions Between Microbes and Minerals, vol. 35 of Reviews in Mineralogy, J. F. Banfield and K. H. Nealson, Eds. (Mineralogical Society of America, Washington, DC, 1997), pp. 86-122.
12. R. L. Penn and J. F. Banfield, Am. Mineral., in press.
13. The definition of twinning was given by G. Friedel, in étude sur les groupements cristallins. (Bulletin de la Société de l'Industrie minérale, Quatreme série, Tomes III e IV, Societe de l'Impreimerie Theolier J. Thomas et C., Saint-Étienne, France, 1904).
14. T. Ito, X-Ray Studies on Polymorphism (Maruzen, Tokyo, Japan, 1950).
15. R. L. Penn and J. F. Banfield, in preparation.
16. A. A. Gribb and J. F. Banfield, Am. Mineral. 82, 717 (1997).
17. R. S. Averback, H. Zhu, R. Tao, H. Höfler, Synthesis and Processing of Nanocrystalline Powder, D. L. Bourell, Ed. (The Minerals, Metals, Materials Society, Warrendale, PA, 1996).
18. Spiral growth about screw dislocations supplies a mechanism for generating a subset of the known polytypes [D. Pandey, A. Baronnet, P. Krishna, Phys. Chem. Miner. 8, 268 (1982); R. S. Mitchell, Z. Kristallogr. 109, 1 (1957)].
19. Spiral growth about screw dislocations supplies a mechanism for generating a subset of the known polytypes [D. Pandey, A. Baronnet, P. Krishna, Phys. Chem. Miner. 8, 268 (1982); R. S. Mitchell, Z. Kristallogr. 109, 1 (1957)].
20. S. Amelinckx, C. R. Acad. Sci. Paris 237, 1726 (1953); W. Dekeyser, Report of the Conference on Defects in Crystalline Solids, July 1954, H. H. Wills Physical Laboratory, University of Bristol, Bristol, UK (The Physical Society, London, 1955). V. G. Bhide, Zs. Krist. 109, 81 (1957); A. Baronnet, Prog. Crystal Growth Charact. 1, 151 (1978).
21. S. Amelinckx, C. R. Acad. Sci. Paris 237, 1726 (1953); W. Dekeyser, Report of the Conference on Defects in Crystalline Solids, July 1954, H. H. Wills Physical Laboratory, University of Bristol, Bristol, UK (The Physical Society, London, 1955). V. G. Bhide, Zs. Krist. 109, 81 (1957); A. Baronnet, Prog. Crystal Growth Charact. 1, 151 (1978).
22. S. Amelinckx, C. R. Acad. Sci. Paris 237, 1726 (1953); W. Dekeyser, Report of the Conference on Defects in Crystalline Solids, July 1954, H. H. Wills Physical Laboratory, University of Bristol, Bristol, UK (The Physical Society, London, 1955). V. G. Bhide, Zs. Krist. 109, 81 (1957); A. Baronnet, Prog. Crystal Growth Charact. 1, 151 (1978).
23. S. Amelinckx, C. R. Acad. Sci. Paris 237, 1726 (1953); W. Dekeyser, Report of the Conference on Defects in Crystalline Solids, July 1954, H. H. Wills Physical Laboratory, University of Bristol, Bristol, UK (The Physical Society, London, 1955). V. G. Bhide, Zs. Krist. 109, 81 (1957); A. Baronnet, Prog. Crystal Growth Charact. 1, 151 (1978).
24. Examples include polymorphs that are long-period interstratifications of serpentine and chlorite, consisting of various proportions of layer types in regularly repeating patterns [J. F. Banfield and S. W. Bailey, Am. Mineral. 81, 79 (1996)].
25. G. Nieh and J. Wadsworth, Scr. Metall. Mater. 25, 955 (1991); D. Sundararaman, Mat. Sci. Eng. B Solid 32, 307 (1995).
26. G. Nieh and J. Wadsworth, Scr. Metall. Mater. 25, 955 (1991); D. Sundararaman, Mat. Sci. Eng. B Solid 32, 307 (1995).
27. H. J. Hofler and R. S. Averback, Scr. Metall. Mater. 24, 2401 (1990).
28. A. A. Gribb, J. F. Banfield, R. L. Penn, unpublished observations.
29. We thank M. Nespolo and T. Kogure (University of Tokyo) and H. Zhang and R. J. Hamers (University of Wisconsin-Madison) for helpful discussions. Funding was provided by NSF grant EAR-9508171, a National Physical Science Consortium Scolarship to R.L.P. (sponsored by Sandia National Laboratories), and Mineralogical Society of America Grant for Student Research in Mineralogy and Petrology to R.L.P.