Nanostructured surfaces

Pattern formation and islands growth control in plasma-condensate system
Kharchenko V.O., Dvornichenko A.V.
Sumy State University, 2 Rimskii-Korsakov St., 40007 Sumy, Ukraine. 
E-mail: vasiliy.kharchenko@gmail.com

We propose a new model to describe first-order phase transitions between low-density state and high-density state and pattern formation with formation of separated adsorbate islands in adsorptive multilayer plasma-condensate systems. We take into account adsorption on a free sites, substratum mediated desorption, vertical and lateral diffusion of interacting adsorbate and the anisotropy in a motion of adatoms between neighbor layers with preferential direction of motion from bottom layers towards lower layers, induced by the electric field presence near the substrate. By assuming that the concentration of adsorbate on layers of multi-layer system decreases with an increase in the number of the layer we derive the one-layer model to describe pattern formation on intermediate layer of multi-layer system. In the framework of stability analysis we have found the phase diagram illustrating ranges of the reduced density of plasma and reduced strength of the electric field, when the self-organization of adatoms into separated adsorbate clusters is possible. By using numerical simulation procedure we discussed an influence of the electric field strength onto dynamics and statistical properties of adsorbate islands, formed on the intermediate layer of the multi-layer plasma-condensate system, meaning formation of well defined separated pyramidal-like adsorbate islands on the substrate.