Understanding the influence of discharge device configuration on atmospheric pressure plasma jet properties and dose delivery of charged particles at plasma jet-substrate interface

Atmospheric pressure plasma jets have been studied extensively in recent years because of their wide range of applications in biomedicine, surface treatments, and material processing. In this work, a two-dimensional simulation study is carried out to compare the axisymmetric discharge device configuration on the fundamental characteristics of an atmospheric pressure plasma jet and delivery dose of charged particle fluxes to the substrate surface. The plasma jets are ignited by inserting a high-voltage needle electrode inside a quartz tube containing a grounded ring electrode (single dielectric material device) or by inserting the high-voltage needle electrode inside a one-end closed quartz tube, which is inside a quartz tube containing a grounded electrode (double dielectric material device). Simulation results of the electron density and electric field show that the single dielectric material device induces a stronger discharge than that of the double dielectric material device with significantly faster propagation of plasma bullet toward to the dielectric substrate. These characteristics of the plasma jet generated by the single dielectric material electrode are accompanied with a higher dose of charged particles delivered to the substrate surface. Shielding of the high-voltage needle electrode in the double dielectric material electrode device can reduce the potential, which, in return, reduces the electric field in the jet channel, and, thus, both the jet velocity and charged particle fluxes to the substrate surface are reduced. In addition, the reduction in the distance between the high-voltage needle electrode and the grounded ring electrode in the double dielectric material device has both double-side effects on the fluxes of the charged particles transported to the substrate surface.