Abstract
The deposition of several monolayers of cobalt on germanium (001) substrates results in the formation of two types of clusters: flat-topped and peaked nanocrystals. Scanning tunneling spectroscopy and helium ion microscopy measurements reveal that these nanocrystals contain cobalt. The shape evolution of the flat-topped and peaked nanocrystals as a function of their size is investigated with scanning tunneling microscopy. For small sizes the nanocrystals are compact. Beyond a critical size, however, the peaked nanocrystals exhibit an elongated shape, whilst the flat-topped nanocrystals remain compact. The shape transition of the peaked nanocrystals is driven by a competition between boundary and strain energies. For small sizes the boundary energy is the dominant term leading to a minimization of the peaked nanocrystal's perimeter, whereas at larger sizes the strain energy wins resulting in a maximization of the perimeter. On the top facet of the flat-topped nanocrystals one-dimensional structures are observed that are comprised of small square shaped units of about 1 nm2. Time-resolved scanning tunneling microscopy measurements reveal that these square shaped units are dynamic at room temperature
Original language | English |
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Pages (from-to) | 924-927 |
Number of pages | 4 |
Journal | Surface science |
Volume | 606 |
Issue number | 11-12 |
DOIs | |
Publication status | Published - 2012 |
Keywords
- METIS-286055
- Optics (see also 3311)Solid state physics (see also 2307)Niet in een andere rubriek onder te brengen
- IR-84669