Characterization Of Pulsed Plasma Research Articles

Electrical and optical characterization of pulsed plasma of N2–H2

This paper considers the electrical and optical characterization of glow discharge pulsed plasma in N2/H2 gas mixtures at a pressures range between 0.5 and 4.0 Torr and discharge current between 0.2 and 0.6 A. Electron temperature and ion density measurements were performed employing a double Langmuir probe. They were found to increase rapidly as the H2 percentage in the mixture was increased up to 20%. This increase slows down as the H2 percentage in the gas mixture was increased above 20% at the same pressure. Emission spectroscopy was employed to observe emission from the pulsed plasma of a steady-state electric discharge. The discharge mainly emits within the range 280–500 nm. The emission consists of N2 (C-X) 316, 336, 358 nm narrow peaks and a broad band with a maximum at λmax = 427 nm. Also lines of N2, N2+ and NH excited states were observed. All lines and bands have their maximum intensity at the discharge current of 0.417 A. The intensities of the main bands and spectral lines are determined as functions of the total pressure and discharge current. Agreement with other theoretical and experimental groups was established.

Characterization of pulsed plasma in unbalanced magnetron argon discharge

Time-resolved probe measurements have been conducted in a unipolar pulsed dc magnetron system to investigate the temporal evolution of plasma parameters, such as the electron density and the electron temperature, and to determine how the driving frequency and the duty cycle of the dc pulse affect these parameters. A new probe measurement system was employed to perform the time-resolved measurements of I-V characteristic curves and their second derivatives with a maximum time resolution of 100 ns. The measurements were performed in a constant voltage mode, constant current mode, and constant power mode, with various pulse frequencies ranging from 5 kHz to 50 kHz and duty cycles ranging from 10% to 90%, to investigate the detailed temporal evolutions of the electron energy distribution function and the plasma parameters. The results show that as the pulse frequency increases, the electron density and the electron temperature exhibit insignificant changes. However, the reduction of the duty cycles results in a significant increase of the electron temperature, irrespective of the operating mode. A comparison of the measured electron energy distribution functions shows that the increase in the electron temperature is caused by a decrease in the population of trapped low-energy electrons and∕or by an increase in the population of drifting high-energy electrons. This result can be explained by considering the electron heating due to the deep-penetrating cathode sheath.