Two West Virginia University physicists and a graduate student are making significant contributions toward optimizing plasma processing.

WVU physics professors Vladimir Demidov and Mark Koepke and graduate student Jon Blessingtonalong with Air Force principal research physicist Charles DeJoseph Jr.recently published innovative findings on plasma processing in the internationally known Institute of Physics Journal of Physics B: Atomic, Molecular and Optical Physics.

The project is a research collaboration between WVU physicists and DeJoseph at the Air Force Research Laboratory at Wright-Patterson Air Force Base in Ohio.

Plasma is used to etch, coat or modify surfaces of materials. Plasma processing is indispensable to the fabrication of electronic components and is widely used in the aerospace industry and other industries.

The long-range goal of the project is to optimize, well beyond the present state-of-the-art technology, both near-wall sheath and plasma for the purposes of nanofabrication and plasma processing,Koepke said.The additional dimension of research capability is broadening student research and educational opportunities in the physics, science and technology of plasmas.

A copy of the study,Investigation of a Radio-frequency Inductive- Coupled-plasma Discharge Afterglow in Noble Gases,is available online athttp://www.iop.org/EJ/abstract/0953-4075/40/19/003. The print version was published Oct. 14.

The study was also recently nominated to be highlighted in European Physics News, a semimonthly journal covering the best in innovative scientific publications.

The project has incorporated a new plasma processing research component into the WVU Plasma Physics Laboratory in the WVU Department of Physics in the Eberly College of Arts and Sciences.

With this project as a spearhead, we have a real chance to develop this new nonlocal plasma technology at WVU ,Demidov said.

Plasma, the fourth state of matter, is thought to be a physical component in 99 percent of the visible universe. It is described as ionized gas because its constituents are charged particlesspecifically, free electrons and ions that were produced when neutral gas becomes ionized.

In the project, pulsed radio waves are responsible for ionizing argon, neon and helium, and the experiments are conducted immediately after the pulse has produced the plasma, Koepke said.

The study explores a novel approach for controlling the nonlocal parameters of the near-wall plasma sheath.

Nonlocality refers to conditions at one point being strongly influenced by conditions elsewhere. The plasma sheath is the interface between the ambient plasma and boundaries such as the chamber walls.

The size of the sheath can be dramatically influenced by what goes on quite a distance from the sheathin the ambient plasmaand this would be considered a nonlocal effect,Koepke said.The sheath will adopt a thickness and a voltage drop that will result in a balance of electrons and ions passing through the sheath in equal numbers.

The influence of a small minority of energetic electrons from the ambient plasma will result in a thickening of the sheath and an increased voltage drop of the sheath so that ion escape will be increased and electron escape will be decreased to compensate the energetic electronscontribution to the electron escape, he noted.

If only the less-energetic 99.99 percent of the electrons participated in this balance, the sheath characteristics would be quite different, and consequently, the plasma processing capabilities related to the energy gained through the sheath, in some ways like the energy gained by water as it falls over a waterfall, would be fundamentally different,Koepke said.In this instance, the energetic electrons emerge from collisions and from the decay of excited neon, argon or helium atoms.

The researchers have given presentations, one of which was featured in an American Physical Society (APS) news report:http://www.aps.org/publications/apsnews/200612/dppmeeting.cfm. The report was one of the top eight highlights in the 2006 APS -Plasma Physics annual meeting that hosted 1,600 scientific presentations.

Blessington, a physics graduate student and Philadelphia native, earned his masters degree on the project and is currently working toward his doctorate. He has presented the results of the project at three international conferences and awaits one in November.

Jon has made great strides in his graduate research project,Koepke said.I am very proud of him and the way he has taken responsibility for performing the experiments.

The Institute of Physics is a scientific membership organization devoted to increasing the understanding and application of physics. It has an extensive worldwide membership and is a leading communicator of physics with all audiences, from specialists through government to the general public.