Investigation of resonance and excimer radiation from a dielectric barrier discharge in mixtures of mercury and the rare gases

Abstract

The excitation of resonance and excimer radiation in mixtures of mercury and the rare gases has been investigated. The gas mixtures were excited in a dielectric barrier discharge. The emission features of such discharges which are mostly in the UV and VUV range were studied in detail. Whereas resonance radiation dominates in mixtures of mercury with He, Ne, and Ar, efficient excimer formation takes place in mixtures of mercury with Kr and Xe. All the emission features of the HgXe excimer which are expected between and around the resonance lines of mercury were found and measured. A theoretical model of HgXe excimer formation is presented. This model takes both the discharge formation and the charged particle kinetics as well as the excimer and excited species formation into account. Experimentally determined Boltzmann temperatures show a decline with mercury density as is predicted by the theory for the average electron temperature. Furthermore it is, e.g., possible to calculate the efficiency of the generation of the various species observed. Due to the geometrical flexibility and high obtainable power levels, dielectric barrier discharges are very well suited for the generation of UV radiation. Apart from well-established techniques like UV lithography, disinfection, or UV curing, also new techniques in photochemistry such as, e.g., photochemical vapor deposition, profit from these new sources.