Spectroscopic Diagnostic of Silicon Plasma Produced by DC and AC Plasma Jet Techniques: Comparative Study

Abstract

In this work, modern technologies use plasma jets in industrial and medical applications for their exciting effectiveness, the properties of which are determined by the type of gas and metal placed as electrodes in the system, as they operate under atmospheric pressure and generate cold plasma, and by using silicon metal and argon gas connected to a high voltage power supply, the current was changed to generate plasma and characterize the produced optical spectrum and compare the effect of this change on its parameters (temperature and electron density) and know the processes associated with its generation. With an applied voltage of 11 kV and using optical emission spectroscopy (OES), the spectral diagnostics were recorded to describe the resulting plasmonic properties. Using DC current, the peak spectral density shown by the results was higher than the alternating current. By comparing the effect of the type of current for the same gas and silicon metal on the parameters, it was found that the values ​​of temperature and electron density at direct current were 2.22-2.67 eV, 3.238×10¹⁶-3.305×10¹⁶ cm^-3, at a gas flow rate of 0.5-2 L/min. At the same flow rate and by applying AC current, it was found that the temperature and electron density were 1.018-1.093 eV, 5.026×10¹⁶-6.897×10¹⁶ cm^-3. Through the comparative study, the effect of direct current was greater on the plasma parameters than alternating current, since alternating current works in the form of an intermittent sinusoidal pulse that affects the movement of charges and thus causes a momentary interruption in the generation of plasma, which leads to cooling the plasma column and reducing the electron density.