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Tunable self-organization of nanocomposite multilayers

Postdocs: Dr. ChangQiang Chen and Dr. JianCun Rao
This work concentrates on the controlled growth and structure evolution of self-assembled nanocomposite multilayers that are induced by surface ion-impingement. The nanoscale structural and chemical information, especially at the growing front, has been investigated with high-resolution transmission electron microscopy. Concurrent ion impingement of growing films produces an amorphous capping layer of ~3 nm thicknesses where spatially modulated phase separation is initiated. The modulation of multilayers, controlled by the self-organization of nanocrystallites below the capping layer, is maintained and is also tunable through the entire film.

nano_multilayers

Figure: (a) XTEM images showing the evolution of multilayers with growing thickness in TiC/a-C nanocomposite films, with (b) filtered inverse FFT image highlighting multilayer waveness, which shows similarity with edge dislocations induced distortion in lattice planes in a crystal, with the maximum fluctuation smaller than a period.