Control over the sp2/sp3 ratio by tuning plasma parameters of the Thermoionic Vacuum Arc

Thermoionic Vacuum Arc (TVA) plasma was used for the deposition of pure, hydrogen-free DLC films. TVA is an original deposition method using a combination of anodic arc and electron gun system for the synthesis of thin films from solid precursors under vacuum of 10(-6)Torr. It was found that, in order to tune amorphous carbon to have a specific sp(3) fraction, the following parameters are essential: filament current (I-r), arc current (l), applied voltage (V) and the distance to the substrate (d). A Philips CM 120 ST TEM system with a Resolution of 1.4 and a 1.4M magnification was used in this work. Other techniques were SAED (Selected Area Electron Diffraction) and FFT (Fast Fourier Transform). Also, the chemical composition of the films was studied with XPS, Mg; SG (W = 1252eV). The sp(3):sp(2) ratio found ranges between 20 and 50%, depending on the electrical parameters. Measured fringes could be indexed using cubic (diamond) structure of carbon, (ICSD 79-1467). (C) 2008 Elsevier B.V. All rights reserved.