AVS 63rd International Symposium & Exhibition
    Plasma Science and Technology Monday Sessions
       Session PS+SE-MoM

Paper PS+SE-MoM11
Plasma-Surface Interactions in Atmospheric Pressure Plasmas: In Situ Measurements of Local Excitations in Thin Films

Monday, November 7, 2016, 11:40 am, Room 104D

Session: Atmospheric Pressure Plasma Processing
Presenter: Scott Walton, Naval Research Laboratory
Authors: S.G. Walton, Naval Research Laboratory
B.M. Foley, University of Virginia
D.R. Boris, Naval Research Laboratory
E.D. Gillman, Naval Research Laboratory
S.C. Hernández, Naval Research Laboratory
A. Giri, University of Virginia
Tz.B. Petrova, Naval Research Laboratory
G.M. Petrov, Naval Research Laboratory
P.E. Hopkins, University of Virginia
Correspondent: Click to Email
The energy flux to a surface during plasma exposure and the associated surface heating are of long standing interest as they contribute to the physicochemical changes associated plasma-based materials processing. The unique feature of plasmas compared to other methods of materials synthesis and processing is that the energy flux is delivered and absorbed at or very near the surface over short time scales, and thus requires fast, surface-sensitive techniques to fully appreciate the dynamics of the plasma-surface interface. To achieve this, we employ pump-probe Time-Domain Thermoreflectance (TDTR) to measure the electron and phonon excitation and energy transport dynamics in thin metal films during exposure to an atmospheric pressure plasma jet. The results show the energy delivered by the plasma jet causes a localized thermal spike that is dissipated radially from the point of contact. More specifically, energy delivered via the flux of particles and photons causes the kinetic energy of the electrons within the material to increase over an area commensurate with the plasma jet radius. That energy is then dissipated through electron-electron collisions and electron-phonon interactions as the excited electrons propagate radially from the point of contact. These results, in conjunction with plasma characterization, will be discussed in an effort to develop a first order understanding of energy transfer and relevant kinetics during plasma jet–surface interactions. This work is partially supported by the Naval Research Laboratory base program.