부산대학교 도서관

An experimental study was conducted to test the effect of changing the frequency of a 10 kV alternating voltage source on the properties of a plasma jet. Optical emission spectra of the plasma were recorded and analyzed. In plasma physics, the electron temperature and density are key parameters. These were determined using a Boltzmann plot and the Stark broadening of the argon line at 763.153 nm, respectively. As the frequency of the alternating voltage source was increased from 10 to 30 kHz (in increments of 5 kHz), the electron temperature increased from 0.995 to 1.357 eV and the electron density rose from 12.027 × 1017 to 12.838 × 1017 cm−3. A strong correlation between the plasma parameters and the frequency of the alternating voltage source was evident. Measurements were also taken on the length of the plasma torch, which was found to grow from 0.041 to 0.051 m as the frequency of the supply voltages was increased. Furthermore, the effect of plasma on the temperature of a silicon target was investigated for a range of frequencies of the supply voltage. It was observed that a slight increase in temperature occurred with increasing frequency, at a constant argon gas flow rate. The effect of plasma jetting on a silicon target was studied at a fixed voltage frequency and a variable gas flow rate. Only a small increase in target temperature was observed. This ensures that no damage or unwanted effects occur on the material being processed.