Diagnostic of 13.56 MHz RF sustained Ar–N₂ plasma by optical emission spectroscopy

¹ Department of Physics, Gomal University, D.I. Khan, Pakistan
² Department of Physics, Quaid-i-Azam University, 45320 Islamabad, Pakistan
³ Department of Physics, Peshawar University, Peshawar, Pakistan
⁴ National Tokamak Fusion Program, 3329 Islamabad, Pakistan

Corresponding author: mzakaullah@qau.edu.pk

Received: 8 January 2008
Revised: 10 July 2008
Accepted: 1 November 2008
Published online: 14 January 2009

Abstract

Optical Emission Spectroscopy (OES) is used to investigate the effect of argon gas mixing on the electron temperature, the degree of nitrogen dissociation and the active species concentration in a 13.56 MHz radio frequency (RF) sustained nitrogen plasma. The electron temperature is determined from Ar-I emission line intensities by using the modified Boltzmann's plot method and is found to be increased with argon mixing in nitrogen plasma. The concentration of active species and is monitored in terms of the emission intensities of nitrogen (0–0) bands of the second positive and the first negative systems respectively. The concentration of active species along with the degree of N₂-dissociation is appreciably enhanced by argon mixing signifying the role of argon metastables in the excitation and dissociation processes.