Naci Ekem

Diamond-like carbon coated on polyethylene terephthalate by Thermionic Vacuum Arc

Diamond-like carbon (DLC) coatings were deposited on transparent polyethylene terephthalate (PET) using a thermionic vacuum arc (TVA) method. The TVA method parameters used to produce DLC coating and the volt—ampere characteristic during the plasma ignition were determined with 22 A of filament current. The crystal orientations and surface morphology of the deposited DLC thin films were investigated using X-ray diffractometer and atomic force microscopy. Reflectance and refractive indices of DLC-coated PET were analyzed by interferometry. According to experimental measurement, DLC-coated thin film was polycrystalline with (1 1 1) and (1 1 0) preferred orientations. Refractive indices were approximately 2.60 in the visible range. DLC-coated PET reflection is close to the PET substrate in the infrared region. According to Fresnel equation, the DLC-coated PET reflection decreased from 19.25% to 10% at 632 nm due to local coating agglomeration. Surface hardness increased to from 2.77 to 10 GPa with DLC coating.

ANTIREFLECTIVE COATING ON POLYETHYLENE TEREPHTHALATE BY THERMIONIC VACUUM ARC

Transparent polyethylene terephthalate (PET) substrates were coated with SiO2 and ZrO2 using thermionic vacuum arc (TVA) method for the first time. The melting point of PET is approximately 260°C. Transmittances, thickness, reflectance, and refractive indices of coated PET samples were measured by ultraviolet—visible spectrophotometer and interferometry to characterize their optical properties. Additionally, scanning electron microscopy, energy dispersive X-ray spectroscopy, and atomic force microscopy were used to characterize the coated PET surface morphologies. Our results show that the SiO2- and ZrO2-coated PET samples had lower reflection when the TVA method was used; so, they show antireflective (AR) properties. Moreover, the coating homogeneity and surface roughness are proper for multi-layer AR coatings.

Study of Metal and Ceramic Thermionic Vacuum arc Discharges

The thermionic vacuum arc (TVA) is a new type of plasma source, which generates a pure metal and ceramic vapour plasma containing ions with a directed energy. TVA discharges can be ignited in high vacuum conditions between a heated cathode (electron gun) and an anode (tungsten crucible) containing the material. The accelerated electron beam, incident on the anode, heats the crucible, together with its contents, to a high temperature. After establishing a steady-state density of the evaporating anode material atoms, and when the voltage applied is high enough, a bright discharge is ignited between the electrodes. We generated silver and Al2O3 TVA discharges in order to compare the metal and ceramic TVA discharges. The electrical and optical characteristics of silver and Al2O3 TVA discharges were analysed. The TVA is also a new technique for the deposition of thin films. The film condenses on the sample from the plasma state of the vapour phase of the anode material, generated by a TVA. We deposited silver and Al2O3 thin films onto an aluminium substrate layer-by-layer using their TVA discharges, and produced micro and/or nano-layer Ag-Al2O3 composite samples. The composite samples using scanning electron microscopy was also analysed.

Investigation of Properties of Boron Thin Film Deposited By Thermionic Vacuum Arc Technology

In this study, we first used boron as anode material in the TVA system. We also present boron thin film deposition using TVA technology.

Analysis of Sterilization Effect of Atmospheric Pressure Pulsed Plasma

We have developed a new technology, the High Voltage Atmospheric Pressure Pulsed Plasma (HVAPPP), for bacteria killing. The aim of this paper is to present a simple device to generate plasma able to kill efficiently bacteria.

Studies on Ag‐Al2O3 Nano‐layer Composite Produced by the Thermionic Vacuum Arc Method (TVA)

Thermionic Vacuum Arc (TVA) is a new type plasma source and generates pure, gas and macroparticle‐free plasma. We generated silver and alumina TVA discharges and we investigated their emission properties. The deposited Ag and Al2O3 layers were imaged using Scanning Electron Microscope (SEM) and analyzed using Energy dispersive X‐ray spectroscopy (EDX).

Emission Spectra of Two Interacting Plasmas

The aim of this present paper is to put in evidence the emission spectral lines of Ar that present M‐effect at the interaction of two different ionized gas flows.

Optical Emission Spectra of Plasma Display Panel

In this study, optical emission spectra of plasma display panel (PDP) was investigated between 200–850 nm at various pressure, pure (Ar) an mixture gas (0,5Ar+0,5 N2). This device is an application of dielectric barrier discharge.

Investigation of the Carbon Produced by Methane Pulsed Discharge

In this paper, we report the new production method amorphous carbon grown on sharpened tungsten electrode at atmospheric pressure by using high voltage pulsed methane discharge.