Time-Resolved Imaging of a Silicon Micro-Cavity Discharge Array

Here, we present a modular constructed metal-grid micro cavity plasma array as a flexible, robust, and simple alternative to micro-structured devices based on silicon. They show great potential for applications requiring large-area treatment, catalytic conversion or decomposition of volatile organic compounds. The metal-grid array is an easily assembled layered structure consisting of a metal grid, a dielectric foil and a magnet. The grid contains between hundreds and thousands of uniformly arranged cavities with a diameter of 150 μm. The whole system is kept together by magnetic force. This also allows disassembling and exchange of the components independently. Typically, the arrays are operated close to atmospheric pressure with an alternating voltage of up to 1.4 kV peak-to-peak in the kHz range. For a first comparison with silicon-based configurations, the metal-grid array is examined from two different perspectives using phase-resolved imaging. The individual cavities show the same asymmetric discharge behaviour as in the silicon-based arrays. In addition, the expansion width of the discharge from the cavities could be measured. The same interaction between the cavities with the propagation of an ionization wave with velocities in the km/s range is observed as for the silicon-based devices. Thus, with respect to the most basic discharge properties, both configurations show the same behaviour, although they are different in structure and composition.

Section: Wave Velocitysupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Modular constructed metal-grid arrays—an alternative to silicon-based microplasma devices for catalytic applications

Dzikowski

Michaud

Böttner

et al. 2020

“…A similar phenomenon of emission propagation has been observed for the 50 × 50 µm 2 microplasma array device [10,11,21]. For this device, we assume that some cavities which differ slightly due to inhomogeneities in the manufacturing process ignite first.…”

Section: Spatial Variationssupporting

confidence: 64%

Excitation dynamics of a kHz driven micro-structured plasma channel device operated in argon

Greb

Boettner

Winter

et al. 2011

The excitation dynamics of a micro-structured plasma channel device with an inverted equilateral triangular cross-section are investigated. This device is operated in argon close to atmospheric pressure with an ac voltage. It is characterized by means of electrical measurements and optical emission spectroscopy. One emission phase is observed in each half-cycle of the applied voltage waveform. Each shows self-pulsing of the device. The integrated intensities for both phases differ by a factor of about two. Phase-resolved wavelength-integrated optical emission spectroscopy which resolves the intensity profile of the plasma channel reveals clear differences between positive and negative half period. Emission features propagating along the discharge channel at velocities of a few km s −1 are observed. Discharge dynamics are compared with those reported for micro-structured atmospheric pressure plasma arrays with discharge cavities of similar triangular cross-section. The comparison allows conclusions on the interaction of individual inverted pyramidal cavities.

“…In previous experiments, phase-resolved investigations of array devices consisting of identical cavities with invertedpyramid profile suggested long-living species as determining for the behaviour [5,9,11,12]. Since the multiple trench array discharge reactors are intended to investigate these assumptions as a prerequisite, it has to be ensured that they and in particular the individual sub-arrays can be compared with the previously investigated devices.…”

Section: Experimental Characterization Of the Multiple Trench Array D...mentioning

confidence: 99%

“…Array devices consisting of identical cavities with inverted-pyramid profile have been investigated by phaseresolved methods [5,9,11,12]. The experiments indicate that the interaction depends in particular on the separation between adjacent micro-cavities.…”

Section: Introductionmentioning

confidence: 99%

Width-dependent interaction of trench-like microdischarges arranged in sub-arrays on a single silicon-based chip

Kulsreshath

Golda

Gathen

et al. 2014

Multiple trench microdischarge reactor arrays based on a silicon (Si) platform were investigated as a concept to overcome production-based errors. The devices incorporated four sub-arrays of trench-like anisotropically etched cavities on a single 2 cm × 2 cm Si chip. Each sub-array consisted of an equal number of structures of equal length, depth and separation only varying in trench width. Experiments were performed in argon (Ar) close to atmospheric pressure at ac frequencies of the order of 10 kHz. The arrays were characterized by means of electrical measurements and by (phase-resolved) optical emission. It is shown that the whole device as well as the independent sub-arrays and the individual cavities behave in a similar way as the inverted-pyramid structures investigated beforehand. Under identical conditions, the voltage required for a first ignition increases with the width of the cavities. For maximum voltages high enough for operation of all sub-arrays, the individual arrays ignite within the excitation period in reverse order. For different excitation frequencies, self-pulsing and emission waves propagating independently across the sub-arrays were observed. Both phenomena show distinct characteristics for the individual sub-arrays being more prominent for the smaller cavities. The observations are interpreted within the frame of a simple physical picture, as a field and a surface-dependent process and the influence of long-living species such as metastables.