Synthesis of graphene by cobalt-catalyzed decomposition of methane in plasma-enhanced CVD: Optimization of experimental parameters with Taguchi method

Abstract

This article describes the significant roles of process parameters in the deposition of graphene films via cobalt-catalyzed decomposition of methane diluted in hydrogen using plasma-enhanced chemical vapor deposition (PECVD). The influence of growth temperature (700–850 °C), molar concentration of methane (2%–20%), growth time (30–90 s), and microwave power (300–400 W) on graphene thickness and defect density is investigated using Taguchi method which enables reaching the optimal parameter settings by performing reduced number of experiments. Growth temperature is found to be the most influential parameter in minimizing the number of graphene layers, whereas microwave power has the second largest effect on crystalline quality and minor role on thickness of graphene films. The structural properties of PECVD graphene obtained with optimized synthesis conditions are investigated with Raman spectroscopy and corroborated with atomic-scale characterization performed by high-resolution transmission electron microscopy and scanning tunneling microscopy, which reveals formation of continuous film consisting of 2–7 high quality graphene layers.

Graphene Synthesis by Inductively Heated Copper Foils: Reactor Design and Operation

“…Many areas were found to have bilayers (40.6%) and multilayers (17.1%). These values are comparable to those of the thermal CVD-grown few-layer (2-3) graphene films [21] and better than of the PECVD [22]. Biand multilayer graphene could be formed by secondary nucleation on monolayer graphene domains.…”

Graphene synthesis by microwave plasma chemical vapor deposition: analysis of the emission spectra and modeling

“…Because the purpose of this work is to establish a reliable and accurate methodology for measuring the gas temperature in a microwave plasma under graphene growth conditions, we will assume that the rotational temperature is representative of the gas temperature for two sets of experiments. In one set, pure H 2 plasma is used at different microwave powers; in the other set, a CH 4 /H 2 mixture gas is used to grow graphene under four optimized conditions based on our previous Taguchi design study combining four growth parameters [76]. Since the transition energy is a characteristic of the species, the central wavelength  is an identifier of the radiating particle.…”

“…In our previous work [76], we used the Taguchi design method coupled with analysis of variance (ANOVA) to determine to the weightage of four parameters (i.e., substrate temperature, methane concentration, growth time and microwave power) during microwave (PECVD) graphene growth on cobalt substrates. To clarify the role of each growth parameter, a systematic study using thermochemical modeling is necessary.…”

One-Step Synthesis of Graphene, Copper and Zinc Oxide Graphene Hybrids via Arc Discharge: Experiments and Modeling

“…For some applications, defects can be intentionally induced in graphene by an electron beam irradiation in order to improve hydrophilic and photoelectrochemical graphene performances [36]. An alternative method to Hummer's [35] and CVD [37][38][39][40][41][42][43] or PECVD [44,45] methods is the electric arc discharge in which carbon is evaporated by implementing direct current DC arc voltage across two graphite electrodes in an inert gas atmosphere. When the electrodes are brought together, discharge occurs by consumption of the anode and plasma formation.…”