Thin Film Instability and Nanostructure Formation: a Molecular Dynamics Study

摘要

One of the recent studies showed that the structures can be self-constructed by controlling the instability of thin fluid film of a nano-scale [S.Y. Chou and L. Zhuang,, J. Vac. Sci. and Technol B, 17, 3197-3202 (1999)]. The Molecular dynamics simulation is used to probe the phenomena. And two sources of instability are investigated: the normal temperature gradient and the long-range attractive potential by the wall. In the first case, the wall temperature is controlled so that the film maintains its temperature gradient. It is observed that the growth rate decreases in a monotonic fashion. The effect of the surface tension gradient, rather than evaporation, may drive the growth. Another source of instability is considered that is the interaction between the upper wall and the fluid film through a potential originating from the interaction between ion and non-polar molecule. The solid potential induces the formation of one or more vertical structures. This may result from the distortion of the pressure distribution.