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Wenchong Wang

Publications and source records attributed to Wenchong Wang.

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Boundary-induced nucleation control: A theoretical perspective

The pre-patterning of a substrate to create energetically more attractive or repulsive regions allows one to generate a variety of structures in physical vapor deposition experiments. A particular interesting structure is generated if the energetically attractive region is forming a rectangular grid. For specific combinations of the particle flux, the substrate temperature and the lattice size it is possible to generate exactly one cluster per cell, giving rise to nucleation control. Here, we show that the experimental observations of nucleation control can be very well understood from a theoretical perspective. For this purpose we perform, on the one hand, kinetic Monte Carlo simulations and, on the other hand, use analytical scaling arguments to rationalize the observed behavior. For several observables, characterizing nucleation control, a very good agreement is found between experiment and theory. This underlines the generality of the presented mechanism to control the deposition of material by manipulation of the direct environment.

physics.chem-ph

Area confined position control of molecular aggregates

We report an experimental approach to control the position of molecular aggregates on surfaces by vacuum deposition. The control is accomplished by regulating the molecular density on the surface in a confined area. The diffusing molecules are concentrated at the centre of the confined area, producing a stable cluster when reaching the critical density for nucleation. Mechanistic aspects of that control are obtained from kinetic Monte Carlo simulations. The dimensions of the position can further be controlled by varying the beam flux and the substrate temperature.

physics.chem-ph