Stranski

Figure 10.5. The three modes of growth of films (a) Frank and van der Merwe s monolayer (two-dimensional) mode (b) the Volmer-Weber three-dimensional mode (c) the Stranski-Krastanov mode involving two-dimensional growth followed by three-dimensional growth.

J. Grilz and Z. Stransky, Acta Univ. Palacki Olomouc, Fac. Rerum. 

Growth theories of surfaces have received considerable attention over the last sixty years as summarized by Laudise et al. [53] and Jackson [54]. The well-known model of the crystal surface incorporating adatoms, ledges and kinks was first introduced by Kossel [55] and Stranski [56]. Becker and Doring [57] calculated the rates of nucleation of new layers of atoms, and Papapetrou [58] investigated dendritic crystallization. 

In practice, uniform films are obtained for only a limited number of film-substrate material combinations (17). The more common experience is that the deposited material forms 3D clusters. The clusters may form directly on the bare substrate, in the Volmer-Weber growth mode, or on top of a very thin but uniform film of the deposit, the Stranski-Krastanov growth mode. We now discuss a method for determining the equilibrium configuration of the deposited material. 

Therefore, we predict that for a system with any finite misfit, a uniform film with a thickness greater than several monolayers is not the equilibrium state the system can lower the chemical potential by the formation of clusters. Clusters will form on either the bare substrate (Volmer-Weber mode any finite misfit with WKl and large misfits if W >1) or on a few layers of uniform film (Stranski-Krastanov mode up to moderate misfits with W>1). This will be true for any system without long-range (e.g. electrostatic) forces. 

NbOx Pt(lll) Stranski-Krastanov growth (distorted Nb06 octahedral) (2)... 

Aufbauend auf Arbeiten von E. W. Muller und Stranski hat M. Drechsler (16) die Berechnung von relativen, flachenspezifischen... 

Stranski-Krastanov growth has been documented for copper on Au(lll) [101, 102], Pt(100) and Pt(lll) [103], for silver on Au(lll) [104, 105], for cadmium on Cu(lll) [106] and for lead on Ag(100) and Ag(lll) [107-109]. In all of these examples, an active metal is deposited onto a low-index plane of a more noble metal. Since the substrate does not undergo electrochemical transformations at the deposition potential, a reproducible surface can be presented to the solution. At the same time, the substrate metal must be carefully prepared and characterized so that the nucleation and growth mechanisms can be clearly identified, and information can be obtained by variation of the density of surface features, including steps, defects and dislocations. 

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