Possibilities of determining non-Maxwellian EEDFs from the OES line-ratios in low-pressure capacitive and inductive plasmas containing argon and krypton

Optical emission spectroscopy (OES) is classically used to determine the electron temperature in low-temperature plasmas by assuming a Maxwellian electron energy distribution function (EEDF). However, non-Maxwellian EEDFs are often found in these plasmas. In this work, we propose an OES line-ratio method that is aimed at obtaining non-Maxwellian EEDFs, with a collisional-radiative model of argon and krypton. When applied for both a capacitively coupled plasma and an inductively coupled plasma, this method provides satisfactory results compared with those measured using a Langmuir probe.