Temperature and electron density measurements in a helium/hydrogen capacitively coupled microwave plasma

Abstract

Various temperature and electron density measurements have been carried out in a capacitively coupled microwave plasma (CMP) with a mixture of hydrogen and helium as the plasma gas using a photodiode array spectrometer for detection. FeI lines were used for excitation temperature, OH lines for rotational temperature and the H gb line for electron number density measurements. Rotational temperatures were found to be between 1800 K and 3000 K, excitation temperatures varied between 2000 K and 5000 K and electron number densities varied between 4 × 10 14 cm −3 and 9 × 10 14 cm −3, depending on operating conditions. The influence of power, observation position, solution uptake rate and carrier gas flow have been investigated.