Impact of N$_2$O and O$_2$ admixtures on pulsed DBDs in N$_2$ at atmospheric pressure

The gas composition is a key parameter that determines basic properties of dielectric barrier discharges (DBDs). N$_2$ is a common working gas for DBD-based plasma processing and N$_2$O is frequently admixed as a precursor in plasma-enhanced chemical vapour deposition of thin oxide layers or for the control of layer stoichiometry in other layer deposition processes. Furthermore, O$_2$ impurities are known to have a strong impact on discharge characteristics and are difficult to avoid. The present contribution investigates systematically the impact of N$_2$O and O$_2$ admixtures on pulsed-driven, single-filament DBDs in N$_2$ at atmospheric pressure. Reaction kinetic modeling was used to analyze the change of plasma-chemical processes for different gas mixtures, and electrical measurements were performed. Similar non-monotonous changes of DBD properties caused by pre-ionization effects were observed both for increasing N$_2$O and O$_2$ content, although the underlying processes were found to be essentially different for N$_2$O and O$_2$ admixtures, respectively. A transition from electropositive to electronegative plasma conditions was found with increasing N$_2$O content, while the admixture of O$_2$ strongly affects the recombination of electrons with positive ions.