ИСТИНА

Carbon nanowall (CNW) films consist of dense arrays of micron-sized flakes of few-layered graphene with dominating vertical orientation on the substrate. Due to a developed surface, high aspect ratio, and high conductivity, CNWs can be used as electrodes in electrochemical current sources, electron field emitters, catalyst supports, black body anti-reflective coatings and others. The most widespread method of CNW synthesis is plasma enhanced chemical vapor deposition (PECVD) from hydrocarbon precursor mixtures. Usually plasma parameters are smoothly changed from discharge breakdown conditions to steady- state that is maintained during further carbon film nucleation and linear growth. Here we investigate how sharp variation of plasma condition can affect the growth of CNWs. The idea is that the new plasma interacts with CNWs grown in the previous period of time modulating their surface. We employed a two dimensional plasma theoretical model and showed that a rapid change in discharge current and gas pressure can be used for fine tuning of the plasma composition that in turn allows us to control hydrogen etching of CNW surface, defect healing or nucleation of secondary nanowalls. The latter for example increased significantly total surface area of the film, which is important for some applications mentioned above.