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6 pags, 7 figs, 3 tabs, A dielectric barrier discharge (DBD) technique has been employed to produce uniform atmospheric plasmas of He and N2 gas mixtures in open air in order to functionalize the surface of filtered-arc deposited hydrogen-free diamond-like carbon (DLC) films. XPS measurements were carried out on both untreated and He/N2 DBD plasma-treated DLC surfaces. Chemical states of the C 1s and N 1s peaks were collected and used to characterize the surface bonds. Contact angle measurements were also used to record the short- and long-term variations in wettability of treated and untreated DLC. In addition, cell viability tests were performed to determine the influence of various He/N2 atmospheric plasma treatments on the attachment of osteoblast MC3T3 cells. Current evidence shows the feasibility of atmospheric plasmas in producing long-lasting variations in the surface bonding and surface energy of hydrogen-free DLC and consequently the potential for this technique in the functionalization of DLC-coated devices. © 2008 Elsevier B.V. All rights reserved., Financial support from the Marie Curie Outgoing Fellowship Grant MOIF-CT-2005-02195 is gratefully acknowledged. Work at Lawrence Berkeley National Laboratory was supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Financial support from the Spanish Ministry of Education under project MAT2004-01451 is also gratefully acknowledged

Optical emission spectroscopy in the range 200-800 nm was applied for investigation of the copper plasma produced by a metal vapour vacuum arc plasma source. The experiments were conducted for the cases when the plasma was guided by straight and Ω-shaped curved solenoids as well as without solenoids, and also for different vacuum conditions. It was found that, besides singly- and doubly-charged ions, a relatively high concentration of excited neutral copper atoms was present in the plasma. The relative fraction of excited atoms was much higher in the region close to the cathode surface than in the plasma column inside the solenoid. The concentration of excited neutral, singly- and doubly-ionized atoms increased proportionally when the arc current was increased to 400 A. Some weak lines were attributed to more highly ionized copper species and impurities in the cathode material.

Energy-resolved mass spectrometry has been used to measure the time-averaged energy and mass distributions of negative ion species in high power impulse magnetron sputtering (HiPIMS) of titanium in an argon/oxygen gas mixture for a number of different discharge conditions. The discharges were found to contain O−, , TiO−, and ions and their respective energy spectra are presented. The oxygen negative ion (O− and ) energy distributions exhibit three broad energy populations (low, medium and high energy) and their origin is discussed. The high-energy peak is found to coincide with a value corresponding to the absolute target potential during the stable on-phase of the HiPIMS pulse. The shape of the high-energy population of O− ions is compared with both a theoretical Thompson energy distribution of sputtered particles and a current-weighted target potential distribution function.A study of the attenuation of high-energy O− ions as a function of the pressure–distance product has been performed. An exponential decrease in intensity of the high-energy O− ions with an increasing pressure–distance product in the substrate region is observed, yielding an effective total cross section of 2.2 × 10−19 m2 for O− interacting with the background gas mixture.

Using a biased quartz crystal microbalance in combination with a gridded electrode, the ionized metal flux fraction in a high power impulse magnetron sputtering (HiPIMS) discharge operated with a titanium target has been investigated. The average discharge power was controlled by varying three different parameters; initial target voltage, pulse width and pulse frequency. The average discharge power was varied from 0.3 to 1.3 kW and irrespective of the power control method used an associated decrease in the flux fraction (from 50% to 30%) was observed. The mechanisms responsible for this decrease in the time-averaged flux fraction of metal ions are discussed.