Initial growth process of carbon nanowalls synthesized by radical injection plasma-enhanced chemical vapor deposition

Abstract

We synthesized carbon nanowalls (CNWs) using radical injection plasma-enhanced chemical vapor deposition. The initial growth process of CNWs was investigated with and without O2 gas addition to a C2F6 capacitively coupled plasma with H radical injection. In the case of the CNW synthesis without the addition of O2 gas, scanning electron microscopy (SEM), transmission electron microscopy, x-ray photoelectron spectroscopy (XPS), and Raman spectroscopy revealed that a 10-nm-thick interface layer composed of nanoislands was formed on a Si substrate approximately 1 min prior to CNW formation. In contrast, with O2 gas addition, SEM and XPS revealed that an interface layer was not formed and that CNWs were grown directly from nanoislands. Moreover, Raman spectroscopy suggested that the interface layer was composed of amorphous carbon and that O2 gas addition during CNW growth is effective for achieving a high graphitization of CNWs. Therefore, O2 gas addition has the effect of reducing the amorphicity and disorder of CNWs and controlling CNW nucleation.

DC Biasing Effects on Properties of Carbon Nanowalls by Microwave Surface-Wave Plasma Chemical Vapor Deposition and Towards Transparent Electrode

“…The growth process of carbon nanowalls has been reported by several groups [21][22][23]. We compare those reports with the results of this study.…”

“…Furthermore, according to a report by Kondo at al. [22], the initial layers contain a large amount of amorphous carbon. Here, the initial layers of the substrate surface layers were graphitized (Fig.…”

Nucleation and Vertical Growth of Nano-Graphene Sheets

“…A 10 nm thick interface layer composed of carbon nanoislands was firstly formed on the Si substrate for a short time, and then CNWs growth began from the nuclei on the interface layer [13]. In order to realize the industrial applications of CNWs with unique characteristics, it is very important to understand the growth mechanism of the initial layer and CNWs to achieve control of the characteristics and morphologies that are appropriate to each application [5][6][7].…”

“…The height (h) of each sample is indicated in each SEM image. [13] The roles of fluorocarbon radicals and hydrogen radicals are discussed. At the top of the growing CNW, the edge would be terminated by CF 3 .…”

Synthesis of Carbon Nanowalls and Few-Layer Graphene Sheets on Transparent Conductive Substrates

“…However, due to variations in the technical details of PECVD setups the quality of the samples can be very different, as is documented in the literature. For example Wang/Zhu et al [13,[27][28][29] and Seo et al [18] used an inductively-coupled RF PECVD with 13.56 MHz, Suzuki et al [17] and Vitchev et al [30] used a MPECVD with 2.45 GHz, and Kondo et al [31] or Hiramatsu et al [20] used a capacitivelycoupled VHF (100 MHz) PECVD system with hydrogen radical injection and C 2 F 6 as carbon precursor. An overview of different methods is shown in Ref.…”