1 / 25

Diffusion on surfaces

Diffusion on surfaces. TR Linderoth et al. Phys. Rev. Lett. 82 (1999) 1494 Aarhus Universitet. Surface Science Course 2006 Achim Schnadt. Surface diffusion is important for. ... growth processes. A. Groß, Theoretical Surface Science , Springer-Verlag. ... surface reactions.

sandra-neal
Download Presentation

Diffusion on surfaces

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Diffusion on surfaces TR Linderoth et al. Phys. Rev. Lett. 82 (1999) 1494 Aarhus Universitet Surface Science Course 2006 Achim Schnadt

  2. Surface diffusion is important for ... ... growth processes A. Groß, Theoretical Surface Science, Springer-Verlag ... surface reactions G. Ertl, Lecture at Nobel Symposium Energy in Cosmos, Molecules and Life, July 2005

  3. Which particles do diffuse on surfaces? Chemisorption, physisorption, and precurors Image from J. V. Barth, Surf. Sci. Rep. 40 (2000) 75

  4. T. Ala-Nissila, R. Ferrando, S. C. Ying Adv. Phys. 51 (2002) 949 Tekniska Högskolan, Helsingfors Brown University, Rhode Island Università di Genova

  5. T. Ala-Nissila, R. Ferrando, S. C. Ying Adv. Phys. 51 (2002) 949 Tekniska Högskolan, Helsingfors Brown University, Rhode Island Università di Genova

  6. Classical movement Quantum tunnelling T. Ala-Nissila, R. Ferrando, S. C. Ying Adv. Phys. 51 (2002) 949 Tekniska Högskolan, Helsingfors Brown University, Rhode Island Università di Genova only for hydrogen!

  7. Some theory ... Following the treatment in A. Groß, Theoretical Surface Science, Springer-Verlag

  8. A. Zangwill, Physics at Surfaces, Cambridge University Press

  9. Initial state – transition state – final state T. Ala-Nissila, R. Ferrando, S. C. Ying Adv. Phys. 51 (2002) 949 Single jump diffusion on a fcc(100) metal surface. A. Groß, Theoretical Surface Science, Springer-Verlag.

  10. What would you expect for the diffusion on a stepped surface? (take into account what you’ve just learned about transition states)

  11. What would you expect for the diffusion on a stepped surface? (take into account what you’ve just learnt about transition states) ”Ehrlich-Schwoebel-barrier” G. Ehrlich, F. G Hudda, J. Chem. Phys. 44 (1966) 1039 R. K. Schwoebel, J. Appl. Phys. 40 (1969) 614

  12. Single (nearest neighbour) jumps Image from T. Ala-Nissila, R. Ferrando, S. C. Ying Adv. Phys. 51 (2002) 949

  13. Single (nearest neighbour) jumps Long jumps Image from T. Ala-Nissila, R. Ferrando, S. C. Ying Adv. Phys. 51 (2002) 949

  14. Single (nearest neighbour) jumps Long jumps Depends on the energy dissipation rate and the temperature! Image from T. Ala-Nissila, R. Ferrando, S. C. Ying Adv. Phys. 51 (2002) 949

  15. Another mechanism for diffusion: Exchange diffusion Transition state Final state Initial state Exchange diffusion on a fcc(100) metal surface. A. Groß, Theoretical Surface Science, Springer-Verlag.

  16. A different view on downward diffusion at steps Image from T. Ala-Nissila, R. Ferrando, S. C. Ying Adv. Phys. 51 (2002) 949

  17. Island diffusion on Pt(110) (2x1) T.R. Linderoth et al. Phys. Rev. Lett. 82 (1999) 1494 Aarhus Universitet

  18. Island diffusion on Pt(110) (2x1) T.R. Linderoth et al. Phys. Rev. Lett. 82 (1999) 1494 Aarhus Universitet

  19. Single-particle diffusion coefficient and chemical diffusion coefficient

  20. Experimental techniques for studying surface diffusion Local probe techniques Field ion microscopy Image from A. Zangwill, Physics at Surfaces. Cambridge University Press Originally from G. Ehrlich, CRC Crit. Rev. Sol. State Mat. Sci. 10 (1982) 391 Scanning tunnelling microscopy M. Schunack et al., University of Aarhus More STM movies on http://www.ifa.au.dk/spm

  21. Experimental techniques for studying surface diffusion Integrating methods Laser-induced thermal desorption

  22. Experimental techniques for studying surface diffusion Integrating methods Quasielastic helium scattering Graphs from A.P. Graham, A. Menzel, J.P. Toennies, J. Chem. Phys. 111 (1999) 1676

  23. Experimental techniques for studying surface diffusion Integrating methods Photoelectron emission microscopy [1-10] O/Pt(110) 50 mm x 190 mm Time between images: 120 s A. von Oertzen, H. H. Rotermund, S. Nettesheim, Surf. Sci. 311 (1994) 322

  24. Want to know more? Experiment review (plus some theory): J. V. Barth, Surf. Sci. Rep. 40 (2000) 75 Theory review (easy to read!): T. Ala-Nissila, R. Ferrando, S. C. Ying, Adv. Phys. 51 (2002) 949

More Related