Ultrasmooth nanocrystalline carbon film induced by low concentration doping: Carbide disorienting graphene nanocrystalliteHits [159] Published :2019-12-06 09:21:22

Ultrasmooth nanocrystalline carbon film induced by low concentration doping: Carbide disorienting graphene nanocrystallite

Carbon 158 (2020) 69-76 （PDF-File）

Cheng Chen, Xue Fan, Dongfeng Diao*

The fabrication of nanocrystalline films is usually accompanied by undesired surface roughening, which limits their applications in tribology, optics and electronics. Here, we report a technique to reduce the average roughness of graphene nanocrystalline carbon film from 18.3 nm to 0.66 nm by ~5 at.% Tidoping. The surface of the Ti-doped graphene nanocrystalline carbon film stay ultrasmooth from few nanometer thick up to 1 mm thick. Based on the nanostructure characterization, the ultrasmooth mechanism is interpreted that Ti-doping leads to the formation of TieC bond, and changes the growth of graphene nanocrystallite from preferred vertical-aligned orientation to random orientation. The ultrasmooth mechanism is general, as shown by similar effects with low concentration doping of Si, Al, Cr, Zr and W. This approach paves a way for fabricating ultrasmooth nanocrystalline carbon films without a requirement of ion-impact-induced downhill current, and significantly improving the hardness of the graphene nanocrystalline carbon film.