Growth morphology of nanoscale sputter-deposited Au films on amorphous soft polymeric substrates

摘要: The growth of a room-temperature sputter-deposited thin Au film on two soft polymeric substrates, polystyrene (PS) and poly(methyl methacrylate) (PMMA), from nucleation to formation continuous is investigated by means atomic force microscopy. In particular, we studied the surface morphology evolution as function deposition time observing an initial three-dimensional island-type growth. Then evolves, with increasing time, hemispherical islands partially coalesced worm-like island structures, percolation, finally rough film. overall discussed in framework interrupted coalescence model, allowing us evaluate critical radius for partial R c=8.7±0.9 nm PS c=7.6±0.8 nm PMMA. Furthermore, application kinetic freezing model allows diffusion coefficient D s≈1.8×10−18 m2/s s≈1.1×10−18 m2/s Vincent us, also, coverage (at which percolation occurs) P c=61% c=56% Finally, dynamic scaling theory growing interface was applied characterize roughening both PMMA PS. Such analyses allow scaling, growth, roughness exponents z=3.8±0.4, β=0.28±0.03, α=1.06±0.05 z=4.3±0.3, β=0.23±0.03, α=1.03±0.05 PMMA, agreement non-equilibrium but conservative linear process phenomenon plays key role.