Abstract
An excimer lamp constructed by a piezoelectric transformer (PT) has been developed and studied in our laboratory. The excimer lamp is based on the excitation of dielectric barrier discharge (DBD) generated by the PT surface that induces high-voltage due to the piezoelectric effect. Spectroscopic measurement in the vacuum ultraviolet (VUV) region is performed for the excimer lamp filling with a He-Xe mixture and Ar. Emission spectra having a peak at 172 and 126 nm are found, which are respectively radiated from the Xe2* and Ar2* excimers that returns to ground states. A self-organization phenomenon (SOP) is also recognized in the He and Ar DBD. Static and time-resolved observations of the self-organized patterns are performed by a single reflex and ICCD cameras, respectively. The formation of self-organized patterns in argon requires a small amount of the air as an additive. From the time-resolved observation, we found dark spots arrayed hexagonally in a weak emission on the PT surface whose arrangement well coincides with that of bright hexagonal filaments. The dark spots are considered as the traces of the accumulated charges on the dielectric electrode, which interrupt the hexagonally filamentary discharges.
