On the Structural, Morphological, and Electrical Properties of Carbon Nanowalls Obtained by Plasma-Enhanced Chemical Vapor Deposition

Abstract

In this study, we investigated the morphological, structural, and electrical properties of carbon nanowall (CNW) structures obtained by plasma-enhanced chemical vapour deposition (PECVD) and underlined the induced effects of argon/nitrogen (Ar/N2) postsynthesis plasma treatment on the electrical behaviour. The top view and cross-section scanning electron microscopy micrographs revealed that the fabricated samples are about 18 μm height, and the edges are less than 10 nm. The Raman analysis showed the presence of the specific peaks of graphene-based materials, i.e., D-band, G-band, D′-band, 2D-band, and D+G-band. The average values of the electrical resistance of fabricated samples were evaluated by current-voltage characteristics acquired at room temperature, in the ranges of 0 V–0.2 V, and an increase was noticed with about 50% after the Ar/N2 postsynthesis plasma treatment compared to pristine samples. Moreover, the Hall measurements proved that the obtained CNW structures had p-type conductivity (Hall coefficient was 0.206 m3/C), and the concentration of charge carriers was 7.8×1019 cm-3, at room temperature.

Carbon-Nanowall Microporous Layers for Proton Exchange Membrane Fuel Cell

“…The vertical form of the individual nanowalls and their height (~6 μm) can be observed in Figure 3a. This patterning was induced by the high values of working temperature and the local electrical field created by the applied power (700 °C and 300 W) which forced the carbon sheets to curl up on vertical walls [34,35]. The structure of the graphene porous network exposes an assortment of tubular open spaces which extend vertically, across the layer, from bottom to top (Figure 3a,b).…”

Influence of Carbon Nanowalls Interlayer on Copper Deposition

“…A sample coated with carbon nanowalls was prepared on K455 steel (OL) by plasma deposition in experimental conditions optimized in previous studies [36][37][38]. SEM images corresponding to this sample are presented in Figure 3a-c, at different magnifications, and the sample was named OL/CNW.…”

“…In addition, copper composite coatings with other carbon structures-graphene or reduced graphene oxide, showed improved mechanical properties (wear resistance, Vickers hardness), and thermal conductivity [28]. Carbon fibers reinforced in a copper metal matrix also offers excellent characteristics, namely good self-lubrication, low thermal expansion, low thermal conductivity, good wear resistance and high mechanical strength [35] Other carbon nanostructures, carbon nanowalls (CNW), were also obtained and presented in our recent publications for electronics (micro-supercapacitors) [36] or bio applications (to mediate biological cells interaction with oxidized silicon substrate) [37,38]. These can be described as networks of interconnected carbon walls with a few to tens of nanometers thickness, grown vertically on a substrate [39].…”

Morphological characterization of carbon nanowalls networks using Minkowski functionals

“…Among nanomaterials, carbon nanowalls (CNWs) are of particular interest for research due to the large specific surface area, mechanical strength, attractive electrical, optical and other properties. [19][20][21][22][23] Most scientists suggest using CNWs for practical applications, in particular for the creation of solar cells, [24][25][26][27] light-emitting diodes, 28,29) sensors, 30,31) superhydrophobic coatings, 32,33) supercapacitors, [34][35][36] storage devices, [37][38][39] black body coating, 40) photo-electrochemical water splitting 41) and etc.…”

“…CNWs are three-dimensional networks with open edges with vertically oriented linked graphene nanosheets, which are freely positioned perpendicular to the substrates and form a labyrinthine surface. [19][20][21] The morphology of such nanostructure as CNWs is unique and the study of its properties for further practical applications is a very urgent task. The morphology is assessed using various analytical devices, in particular, scanning electron microscopy and scanning probe microscopy, 23,42) however the analysis of the obtained results requires additional tools, in particular special software and methods.…”