Untitled

The recovery of glow-plasma structure in atmospheric radio frequency microplasmas at very small gaps

“…Of course this transition gap is also affected by the chemistry in plasmas and the power of discharges. 2,9 This reduction implies that in high frequency rf discharges over 13.56 MHz, the SDP structure would not be very easy to be observed in experiments because the structure transition will happen at very small size even below 100 lm. On the other side, the GP structure with quasineutral bulk region can still be sustained even in very small dimensions if the excitation frequency is high enough, and the generated plasmas with larger electron density may be important to many applications at small gaps; however, the microplasmas produced under these conditions may lose some unique properties discussed in Refs.…”

“…Atmospheric microplasmas have commanded much attention in recent years due to the considerable scientific depth and potential applications. [1][2][3][4] For atmospheric capacitively radio-frequency (rf) discharges, when the electrode gaps are confined to submillimeter dimensions, the generated microplasmas show many unique properties compared to the large-scale atmospheric plasmas, 3 such as the high energetic electrons, 5 different discharge structures, 6,7 and nonequilibrium characters. 8 The experimental 6 and computational studies 5,7 have demonstrated that in atmospheric rf discharges at 13.56 MHz, with the electrode gap reduced, the traditional glow-plasma (GP) structure will eventually transit to a new sheath-dominated-plasma (SDP) structure, where the sheath region occupies a large portion of the electrode gap and almost no distinct bulk plasma region develops.…”

“…The experimental diagnosis of atmospheric microplasmas, however, is facing many new challenges due to the small dimension and high gas pressure, 3,4 and numerical simulations provide a valuable alternative for investigating the properties of microplasmas. 2 In this letter a one-dimensional fluid model is explored to study the transition of discharge structures in capacitively rf discharges at atmospheric pressure. 11,12 Briefly, the continuity equations with the drift-diffusion approximation are used to describe the dynamic behaviors of the plasma species, and Poisson's equation is applied to obtain the electric field between the electrodes.…”

Electron Beam Assisted Patterning and Dry Etching of Nafion Membranes

“…To improve performance, several strategies have been investigated to tailor the morphology of the catalyst layer (CL)-Nafion interface by patterning the Nafion membrane. These include, surface roughening by abrasion, 11 Ar þ bombardment, 12,13 laser modification, 14 Ar/SF 6 , He/H 2 , and Ar/O 2 plasma treatments, 13,[15][16][17] and nanoimprint lithography. 18,19 In order to form the nano-or micro-patterns in Nafion in a controlled and reproducible fashion, we propose a novel technique employing electron beam (e-beam) lithography coupled with dry etching strategies.…”