Dynamical level-crossing model for the time-dependent electron emission from dielectric surfaces in symmetric dielectric barrier discharges

Purnima Ghale, Harley T. Johnson

Research output: Contribution to journalArticle

Abstract

In field emission plasmas, electrons that initiate plasma formation come from the surface of a metallic electrode, or wall, with emission controlled by the electron-work function of the wall, and can be computed via the Fowler-Nordheim formula. Impinging ions modify the rate at which electrons leave the surface, and are accounted via the coefficient of secondary electron emission. However, in the case of dielectric surfaces, the microscopic mechanism by which electrons are emitted is not as well understood. While simulations of dielectric barrier discharge plasmas assume an initial density of electrons in a time-dependent simulation, whether the presence of electrons is a necessary ambient condition or whether it is a result of emission from a surface is not clear. This is particularly relevant in the context of micro and nanoscale plasma generators when surface-related effects become more important. Here we consider electron emission from dielectric surfaces in the context of dielectric barrier discharges. The configuration of interest consists of two parallel-plate metallic electrodes, each covered by a dielectric layer. Assuming that the initial electrons for plasma formation arise from the surface, we compute the rate of charge transfer from surfaces, which is a necessary, but not sufficient, condition for plasma formation. This paper presents the application of the theory of nonadiabatic transitions (dynamical level crossing) to the problem of electron emission from dielectric surfaces in dielectric barrier discharges. The microscopic model of electron transfer described here has potential applications in the design of micro and nanoscale plasma generators.

Original languageEnglish (US)
Article number155405
JournalPhysical Review B
Volume99
Issue number15
DOIs
StatePublished - Apr 4 2019

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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