Date of Graduation
1997
Document Type
Dissertation/Thesis
Abstract
From lightning in the summer sky to the neon lamp outside of the department store, electrical discharges have become commonplace fixtures in many aspects of everyday life. Although these devices have been present for a significant time period, their principals of operation are still only vaguely understood. The focus of these studies is to characterize a particular analytical plasma, the glow discharge, and more specifically, to develop a better understanding of the fundamental processes that occur during power modulated operation. The characterization of both power modulated r.f. and d.c. glow discharge plasmas was performed using mass spectrometry as well as optical spectroscopic techniques. Studies were designed to facilitate the monitoring of gas phase plasma chemistry during distinct temporal regions of the modulated plasma's pulse cycle. The time regime occurring just after pulsed power termination affords enhanced analyte sensitivity with the suppression of signal contributions from contaminant species. These benefits are not possible while operating under steady state conditions. A concrete understanding of these temporally exclusive processes is essential to maximize the analytical utility of pulsed plasma operation. The glow discharge plasma is also considered as a reactor for the deposition of diamond thin films. Both steady state and modulated argon plasmas diluted with CH{dollar}\\sb4{dollar} were characterized by mass spectrometry to assess their utility for diamond synthesis. The focus of studies performed using the Ar/CH{dollar}\\sb4{dollar} discharges is the optimization of experimental parameters that preferentially form the activated species essential for high quality diamond film growth. Some of the information accrued from the Ar/CH{dollar}\\sb4{dollar} work was then applied to a technique utilizing a similar hydrocarbon gas, CF{dollar}\\sb4{dollar}, but with drastically different results. Dilution of an argon plasma with a fluorinated species induces a process known as chemical etching. The driving force behind this preliminary work is to develop an alternative method for the analysis of nonconducting samples.
Recommended Citation
Steiner, Robert Ernest, "The characterization of pulsed glow discharge phenomena by mass spectrometry and optical spectroscopies." (1997). Graduate Theses, Dissertations, and Problem Reports. 9832.
https://researchrepository.wvu.edu/etd/9832