Ground State and Excited State H-Atom Temperatures in a Microwave Plasma Diamond Deposition Reactor

Ground electronic state and excited state H-atom temperatures are measured in a microwave plasma diamond deposition reactor as a function of a low percentage of methane introduced in the feed gas and the averaged input microwave power density. Ground state H-atom temperatures (TH) and temperature of the H-atom in the n=3 excited state (THα) are obtained from the measurements respectively of the excitation profile by Two-photon Allowed transition Laser Induced Fluorescence (TALIF) and the Hα line broadening by Optical Emission Spectroscopy (OES). They are compared to gas temperatures calculated with a 1D diffusive non equilibrium H2 plasma flow model and to ground electronic state rotational temperatures of molecular hydrogen measured previously by Coherent Anti-Stokes Raman Spectroscopy.