Investigating recent developments and applications of optical plasma spectroscopy: A review
Angela R. Hanna, Ellen R. Fisher
Abstract
Optical spectroscopy is a powerful, nonintrusive diagnostic tool that can provide unparalleled insight into fundamental plasma properties. Specifically, these techniques are widely employed to qualitatively and quantitatively characterize interactions of species within a discharge. This work is comprised of two parts: (1) a brief review of recent literature on the application of optical emission spectroscopy from the past decade, ranging from the study of atomic rare gas to more complex environmentally and technologically relevant plasma systems and (2) the presentation of new data that illustrate the power of optical spectroscopy techniques beyond simple species identification. Specifically, time-resolved optical emission spectroscopy was utilized to provide kinetic information about excited state species formation, ultimately lending mechanistic insights into a range of plasma processes. In addition, by combining optical emission and broadband absorption spectroscopies, rotational and vibrational temperatures for both excited and ground state species were determined. These data provide a thermodynamic base for enhanced understanding of the fundamental chemistry in plasma systems. The two platforms explored here were plasma-assisted catalysis systems containing NxOy species and fluorocarbon plasmas utilizing a range of precursors to evoke either etching or deposition, depending on the plasma conditions.