Synthesis and Characterization of carbon nanomaterials obtained in Ar/C₂H₂ DC glow discharge plasma

This research focuses on the synthesis and characterization of carbon nanomaterials in a DC glow discharge plasma using an Ar/C₂H₂ gas mixture. The operating parameters: p = 1 Torr and U = 1 kV. The working gas mixture is composed of Ar and C₂H₂ in a ratio of 98% to 2% [1]. The primary aim is to investigate the dynamic behavior, morphology, and surface properties of the synthesized DLC films and NPs.

Plasma ignition was carried out in a cyclic mode at various time intervals (10–60 seconds). OES was employed to investigate the dynamics of plasma parameters, particularly the electron temperature. During acetylene injection, the electron temperature exhibited significant transient fluctuations. These variations were found to be closely related to the dynamics of nanoparticle nucleation and agglomeration processes.

NPs were synthesized at the anode and characterized using SEM and AFM. SEM and AFM images revealed a uniform distribution and detailed surface morphology of the nanoparticles. The DLC films formed on the cathode were analyzed by Raman spectroscopy, XPS, UPS and XRD. Raman spectra confirmed the presence of both sp² and sp³ carbon bonding configurations, while XPS data verified the existence of C–C, C–H, and oxygen-containing functional groups. UPS was employed to determine the work function of the DLC films. XRD analysis indicated an amorphous structural nature [2].

Fig.1 presents SEM and AFM images of the fractal structures. Such fractal growth was observed under experimental conditions involving a 50/50 volumetric mixture of argon and acetylene gases, an applied voltage of 5 kV, and a pressure of 1 Torr.



Fig.1 – Images of the fractal growth (a) AFM and (b) SEM