Spatially-resolved spectral analysis of Ar-NH3 plasma jet

Summary form only given. Like-glow plasma is frequently observed in ambient helium gas with dielectric barrier discharge (DBD). Actually, the high cost of helium makes it unsuitable for application. Therefore, a replaceable gas or mixture gases is necessary. As our reported work, like-glow plasma jet was obtained by adding a little ammonia (NH₃) into argon. In this work, spatially-resolved spectra of argon atmospheric pressure plasma jet (APPJ) with different proportions of ammonia are captured by using a mechelle spectrometer system. The electrode configuration consists of two copper strips (10mm width) which are wrapped around a hollow quartz tube with inner and outer diameters of 2mm and 4mm, respectively. The argon gas flow is fixed at 3slm (standard liter per minute) with the ammonia gas flow adjustable.From analysis of captured spectra, we can fmd that the plasma productions major include a lot of radicals (NH, OH etc.), excited atomic Ar species (metastable and high excited Ar), and excited atomic 0, etc .. When the argon gas flow is 3slm and ammonia is 0.6sccm (standard cubic centimeter per minute), the intensity of NH and OH spectra bands decrease from upstream of grounded electrode to the end of plasma jet. At nozzle of tube, the line intensity of these spectra decreases gradually with increasing proportion of ammonia. It can be explained by considering the penning effect between metastable atomic Ar* and Amolecular ammonia (NH3), as well as electronegativity of NH3.