Four free parameter empirical parametrization of glow discharge Langmuir probe data

Abstract

For the purpose of developing a simple empirical model capable of producing the electron energy distribution function (EEDF) from Langmuir probe I-V characteristics, a four parameter empirical equation that fits most Langmuir probe experimental data is suggested. The four free fitting parameters are related to the main plasma properties. These properties include the ion and electron saturation currents and the plasma electron temperature. This equation can be readily differentiated twice to give the EEDF according to the Druyvesteyn formula. Furthermore, a MATLAB platform based computer code based on this model yielding results for the plasma potential and all plasma parameters mentioned above is presented. The information given below can be used to write other computer codes for the same purpose in any other programming language.

Plasma characterization in CW and pulsed mode and its effect on beam current in 2.45 GHz ECR Ion source

“…At the end of the scan, the Langmuir probe I-V characteristics is plotted as shown in figure 7 and stored in .csv file format. The Langmuir probe theory is described in [14][15][16]. Here, we are interested mainly in plasma electron temperature (𝑇 𝑒 ) and plasma electron density (𝑛 𝑒 ).…”

Investigation of the Electron Energy Distribution Function in Capacitively Coupled (13.56 MHz) Radio Frequency Discharge in Dry Air

“…The basic trick used for obtaining the EEDF is the exploitation of the Druyvisteyn formula: …. 1Where m is the electron mass, e is the electron charge, A is the probe area, n is the electron density, I is the probe current and V is the probe voltage (Azooz, 2008). EEDF could easily be computed from the second derivative of the voltage-current which was employed in order to extract the EEDF from the voltage-current characteristic of a Langmuir probe, either by using analog devices or numerical methods.…”