The article introduces the plasma evolution of dielectric barrier discharge driven by the pulsed waveforms. The model is established under the Afivo adaptive grid framework and PIC-MCC simulation method. Through introducing the heavy particle reaction process, such as ion drift motion, photoemission, the accumulation and mapping of surface charges, and twobody radiative recombination process, the details of the plasma forming process and distribution is discussed. . The study yielded the evolution of electron and ion distributions under a time-varying electric field, corresponding alterations in potential and electric field induced by charged particle motion, are obtained under the first pulse of dielectric barrier discharge (DBD) structure at 2 kPa argon. The simulation results reveal the inceptive discharge evolution at the rising edge of pulse, the discharge extinction occurred near the upper dielectric layer is induced by the reverse electric field formed by the surface charge accumulation at the pulse duration period, and the second plasma packets in the entire cavity is obtained at the falling edge of the pulse. Meanwhile, the time resolved plasma discharge intensity distribution is obtained by ICCD, and the comparison and explanation of the result is discussed with the proposed simulation model. The key factor of formation of plasma sheath at different time period and the verification of simulation result is discussed. The proposed model is of great significance for exploring the evolution of plasma dynamics and the evolution of long pulse width discharges by analyzing the evolution process of discharge points during the first pulse, which is non steady state.

An exploration of discharge efficiency and uniformity improvement by using pre-ionized bipolar pulse method in dielectric barrier discharge (DBD) device under atmospheric pressure is conducted. Through utilizing the pre-ionized charged particles on the dielectric surface, the amplitude of the applied pulses for sustaining discharge can be significantly decreased. By analyzing the influence of “built-in” electric field from surface charges on discharge efficiency and uniformity, a scheme of pre-ionized bipolar pulse method is proposed. Since the property of “built-in” field is closely dependent with pre-ionized pulse parameters, such as amplitude, pulse number, and polarity, the discharge uniformity and efficiency under different combinations of pre-ionized pulse parameters are investigated. According to experimental results, the discharge efficiency of the proposed method is increased by 11.8% and 17.4%, and the production efficiency of active species of N₂(C³Π_u→ B³Π_g) is increased by 10.4% and 89.5% compared with a conventional bipolar pulse and positive pulse method, respectively, in ambient air. Moreover, the uniformity of DBD discharge is improved, and the maximum intensity difference between discharge regions is decreased from ∼20% to ∼5% compared with the one driven by the conventional positive pulse.

Different spatiotemporal modes of ionization wave propagation at opposite polarity of bipolar pulses in a micro-dielectric barrier discharge structure device are investigated. The device is fabricated on a heavily doped n-type silicon substrate, and a 1 cm × 1 cm square cavity is formed on the 180 μm-thick polyimide film. Different modes of ionization wave propagation determined by the polarity of bipolar pulses are observed, and the details of streamerlike mode and wavelike mode under positive and negative half cycles of pulses are investigated, respectively. The propagation speeds of streamerlike ionization waves and wavelike ionization waves are ∼120 km/s and ∼40 km/s on average and ∼150 km/s and ∼70 km/s in maximum, respectively. Different parameters of bipolar pulses, especially the rising time of pulses, are applied to the proposed device to explore the variation of ionization wave propagation properties. The results show that the modes of the ionization wave propagation are barely changed when the device is driven by different rising time pulses. However, the initial plasma generation time and propagation speed are greatly changed. With a decrease in the rising time from 400 ns to 50 ns, the initial plasma generation time is brought forward over 200 ns, and the ionization wave propagation speed is improved over 30% for both cases. The results imply great significance in the exploration of the dynamics of plasma discharge evolution and regulation of plasma discharge properties through manipulating the pulse parameters.

The electrical characteristics and stability of indium gallium zinc oxide (IGZO) thin film transistors (TFTs) are improved through surface single crystallization of IGZO film by Cs ions adsorption at room temperature. The experimental results show that the Cs ions can bond with the oxygen ions in IGZO film, changing surface structure of IGZO film from amorphous to a single crystalline. The electrical properties and stability of surface single crystalline IGZO and a-IGZO based thin film transistors were investigated, respectively. With the introduction of the surface single crystalline of the IGZO film, the electrical properties of TFT were greatly improved, showing that the carrier mobility improved from 5.28 cm ² V ⁻¹ s ⁻¹ to 8.84 cm ² V ⁻¹ s ⁻¹ , and the threshold voltage deceased from 7.6 V to 2.3 V, accompanied with a leakage current below 10 ⁻¹⁵ A. The stability of V _th shifts in surface single crystalline IGZO based TFT was 6.3 V under V _GS = 20 V for 5000 s, improved by ∼32% compared with that of a-IGZO TFT.

Self-organization of periodic, streamer-like ionization waves in planar microplasma devices having a dielectric barrier discharge structure is observed. In contrast to plasma propagation in arrays of microchannels or microcavities, the ionization waves originate from a single point but rapidly sub-divide into as many as 10 ‘branch’ plasma wave packets that eventually recombine. In less than 70 ns, the self-organization of the spatially-periodic array of co-propagating branches is complete and two successive sets of waves, separated in distance and time by ∼1.8 mm and ∼50 ns, respectively, are generated. The mean propagation velocity of each plasma packet is greater than 70 km s ⁻¹ but values as large as 150 km s ⁻¹ have been measured. Because the propagation path for all subsequent streamers is established by the first set of plasma packets, the intensity of the second set is noticeably enhanced. The average length of the primary branches is ∼1.5 mm but reaches a maximum of ∼4.5 mm as the wave packets travel an overall distance of 1 cm. These phenomena are interpreted in terms of photoelectron emission from the floor and walls of the shallow dielectric microcavity, induced by radiation from the advancing packets, and the rapid collapse of the sheath of each microplasma owing to the accumulation of charge on the underlying dielectric. The spatial profiles of the propagating plasmas suggest that generating and probing plasma solitons may now be feasible.