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2 Optica Applicata

2 2009

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Fabrication and electrochemical properties of diamond layers grown on tungsten wire by HF CVD method

Torz-Piotrowska R., Uniszkiewicz C., Szreiber M., Wrzyszczynski A., Staryga E., Runka T., Kasprowicz D.

Optica Applicata

2009

Vol. 39, nr 4

951-957

Un-doped polycrystalline diamond thin films have been grown on tungsten substrates by hot filament chemical vapor deposition (HF CVD) using a hydrogen and methanol vapor mixture. Diamond films have been analyzed by Raman spectroscopy and scanning electron microscopy (SEM). Cyclic voltammetric behavior of diamond films of different quality and morphology has been studied in acetonitryle with (n-Bu)4NClO4 and in 0.1 M KCl aqueous solutions. Preliminary cyclic voltammetry (CV) measurements showed that our electrodes have a wide potential range over which negligible background response current is observed. The potential windows depend on the type of solvent. In the case of water solution the decomposition of water occurs electrochemically and evolves O2 during positive (anodic) polarization and H2evolution during negative (cathodic) polarization. The electrochemical properties of diamond electrodes have been evaluated by performing cyclic voltammetry measurements in [Fe(CN)6]3-/4- with 0.1 M KCl. The electrode demonstrates reversible kinetics during electrochemical analysis.

Electron paramagnetic resonance and scanning electron microscopy characterization of diamond films fabricated by HF CVD method

Fabisiak K., Szreiber M., Uniszkiewicz C., Runka T., Kasprowicz D.

Optica Applicata

2009

Vol. 39, nr 4

833-837

Defects in diamond films, produced by the hot filament chemical vapour deposition (HF CVD) of methanol and hydrogen mixture as function of gas composition, were investigated by electron paramagnetic resonance (EPR), scanning electron microscopy (SEM) and Raman spectroscopy measurements. We found an isotropic g-value (2.003š0.0002) independent of growth conditions. The peak-to-peak of EPR line width changes from 0.3 to 0.6 mT and the spin density increases from 2.3ź1017 to 3.2ź1018 spin/cm-3 with increasing concentration of methanol vapour. The EPR line in general shows double character and was found to be superposition of two components, a narrower Lorentzian and a broader Gaussian, suggesting the existence of two different types of defects in diamond layer. EPR measurements were supported by SEM observation.