The European Physical Journal Applied Physics

Plasma, Discharges and Processes

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

F. U. Khana1, N. U. Rehmana2, S. Naseera3, M. A. Naveeda2, A. Qayyuma4, N. A.D. Khattaka1 and M. Zakaullaha2

Department of Physics, Gomal University, D.I. Khan, Pakistan

Department of Physics, Quaid-i-Azam University, 45320 Islamabad, Pakistan

Department of Physics, Peshawar University, Peshawar, Pakistan

National Tokamak Fusion Program, 3329 Islamabad, Pakistan


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 $\rm N_2(C ^3\Pi_{\it u})$ and $\rm N_2^+ (B ^2\Sigma_{\it u}^+)$ 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 $\rm N_2 (C^3\Pi_{\it u})$ 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.

(Received January 8 2008)

(Revised July 10 2008)

(Accepted November 1 2008)

(Online publication January 14 2009)


  • 52.80.Pi – High-frequency and RF discharges;
  • 52.70.Kz – Optical (ultraviolet, visible, infrared) measurements;
  • 81.65.Lp – Surface hardening: nitridation, carburization, carbonitridation;
  • 51.50.+v – Electrical properties