Generation and characterization of field-emitting surface dielectric barrier discharges in liquids

Abstract

Field-emitting surface dielectric barrier discharges (FESDBDs), previously generated in CO2 from high pressures up to supercritical conditions using 10 kHz ac excitation, were investigated in non-aqueous liquid CO2 and liquid silicone oil. In both liquids, the maximum amount of negative charge Q−deposited as a function of the applied voltage amplitude was consistent with the Fowler–Nordheim equation, which demonstrated the presence of field emission. Furthermore, purely continuum optical emission spectra attributable to electron-neutral bremsstrahlung were confirmed. The fact that these characteristics were identical to those in high-pressure CO2 reported from previous research shows that FESDBDs can be generated independently of the medium type and that they are low-power (on the order of 10 mW) discharges. To investigate the charging function of FESDBDs, the motion of fine particles suspended above the FESDBDs was studied by high-speed imaging. It revealed that the speed of fine particles affected by the FESDBDs depends on the particle size, the FESDBDs' function being to charge fine particles.

Spatiotemporal optical emission spectroscopy to estimate electron density and temperature of plasmas in solution

“…in which hν, E, c, n n, λ, k, and m e are the emitted photon energy, the electron energy, the speed of light, the neutral particle density, the emitted wavelength, the Boltzmann constant, and the electron mass, respectively. The calculated profile indicates that the maximum value and slope with the wavelength of the continuum spectrum depends on the electron temperature [37][38][39][40][41].…”

Communication—Development of Discharge-Assisted Electrophoretic Deposition and Demonstration for TiN Deposition

“…This structure was essentially the same as that used in our previous research. [38][39][40][41][42][43][44] However, the difference exists only in the shape of the powered electrode, which was designed in a 10 mm × 5 mm comb shape to increase the discharge area. A DCbiased silicon substrate, with an area of 10 mm × 5 mm was used as the third electrode for depositing fine particles.…”

“…Upon applying a 10 kHz sinusoidal high voltage (0-5 kV p−p ) to the FESDBD electrode using a function generator and a high-voltage amplifier, the DC voltage was immediately applied to the silicon substrate to deposit the film. Because the electric charge was expected to be negative based on our previous research, 41 the applied DC voltage was positive (+ 0-4 kV). The duration of the application of both voltages was equal to the film-deposition time.…”

“…FESDBD has been observed in high-pressure CO 2 , N 2 , Ar, and liquid silicone oil, and its generality has been confirmed through numerous studies. [38][39][40][41][42][43][44] In high-density media, the generation of FESDBD has been confirmed at relatively low applied voltages compared to standard high-energy discharge methods; this is an attractive feature for the discharge process in liquids. In addition, FESDBD employs a simple electrode structure and creates a larger discharge area compared to the conventional needle electrodes used for emitting electrons via field emission.…”

“…[45][46][47][48] Silicone oil was used to disperse the TiN particles, for which the generation of FESDBD was observed in our previous study. 41…”