On the influence of metastable states and the behavior of the EEDF in the characterization of the negative glow of a N2 -Ar discharge by OES

ISOLA, L M; LOPEZ, M; GOMEZ, B J; GUERRA, V

Journal of Physics: Conference Series

IOP

Año: 2014 vol. 511

1742-6588

Optical emission spectroscopy (OES) is an essential diagnostic technique in many plasmasystems, such as those used for surface treatments or fabrication of thin films. Despite thesimplicity of application of OES, its interpretation is not straightforward. In particular, itrequires the use of models, which due to the complexity and variety of discharge conditions,have not yet been fully understood [1]?[3].In addition, Langmuir probes have been widely used to characterize plasmas. They allowthe measurement of several parameters of interest, such as the electron density and temperature,as well as the determination of the electron energy distribution function (EEDF) by numericalderivation of the characteristic V − I [4] or by probe-current modulation [5].In this work, some second positive system bands in the negative glow of an Ar-N 2 plasma ata pressure of 2.5 Torr were investigated both by OES and Langmuir probes, for different mixtureconcentrations. The main purpose of this study was to verify how metastable states and thebehavior of the EEDF may influence the interpretation of OES data.