High-Density Polyethylene(HDPE) Surface Treatment Using an RF Capacitive Atmospheric Pressure Cold Ar Plasma Jet

In this study,a high-density polyethylene（HDPE,5-mm-thick,0.95 g/cm3） surface was treated using an RF capacitive atmospheric pressure cold Ar plasma jet.By using this Ar plasma jet,a hydrophilic HDPE surface was formed during the plasma treatment.In particular, the effects of an additive gas（N;or O2） on the HDPE surface treatment were investigated in detail.It was shown that the addition of N2 or O2 gas had an important influence on the HDPE surface treatment.Compared to pure Ar plasma treatment,a lower value of water contact angle （WCA） was obtained when a trace of N2 or O2 gas was added.It was also found that besides the quantities of active species in the plasma jet,the treatment temperature played an important role in the HDPE surface treatment.This is because surface molecular motion is not negligible when the treatment temperature is close to the melting point of the polymer.

Structural evolution of silicone oil liquid exposed to Ar plasma

Structure properties of silicone oil serving as a liquid substrate exposed to Ar plasma axe investigated in this paper. Under the action of energetic Ar ions, the surface of silicone oil liquid substrate exhibits a branch-like fractal aggregation structure, which is related to the structure evolution of silicone oil liquid from Si-O chain to Silo network. The radicals from the dissociation of silicone oil molecule into the Ar plasma turns the plasma into a reactive environment. Therefore, the structural evolution of silicone oil liquid substrate and the reactive radicals in the plasma space become possible factors to affect the aggregation of nanopaxticles and also the structures and the compositions of nanopaxticles.

Measurement of the O_2 Dissociation Fraction in RF Low Pressure O_2/Ar Plasma Using Optical Emission Spectrometry

Measurement of the oxygen dissociation fraction in RF low pressure oxygen/argon plasma using optical emission spectrometry is presented. The oxygen dissociation fraction and its evolutions as functions of operational parameters were determined using argon as the actinometer. At a pressure of 30 Pa, the oxygen dissociation fraction decreased from 13.4% to 9.5% as the input power increased from 10 W to 70 W. At an input power of 50 W, the oxygen dissociation fraction decreased from 12.3% to 7.7% when the gas pressure increased from 10 Pa to 40 Pa. The influences of operational parameters on the generation of atomic oxygen were also discussed.

Analysis of an Ar plasma jet in a dielectric barrier discharge conjugated with a microsecond pulse

In this work, an Ar plasma jet generated by an AC-microsecond-pulse-driven dielectric barrier discharge reactor, which had two ring-shaped electrodes isolated from the ambient atmosphere by transformer oil, was investigated. By special design of the oil insulation, a chemically active Ar plasma jet along with a safe and stable plasma process as well as low emission of CO and NOxwere successfully achieved. The results indicated that applied voltage and frequency were basic factors influencing the jet temperature, discharge power, and jet length, which increased significantly with the two operating parameters. Meanwhile, gas velocity affected the jet temperature in a reverse direction. In comparison with a He plasma jet, the Ar plasma jet had relatively low jet temperature under the same level of the input parameters, being preferable for bio-applications. The Ar plasma jet has been tested to interact with human skin within 5 min without the perception of burnt skin and electrical shock.

Optical Emission Spectroscopic Studies of ICP Ar Plasma

The ion line of 434.8 nm and atom line of 419.8 nm of Ar plasma produced by an inductively coupled plasma （ICP） were measured by optical emission spectroscopy and the influences from the working gas pressure, radio-frequency （RF） power and different positions in the discharge chamber on the line intensities were investigated in this study. It was found that the intensity of Ar atom line increased firstly and then saturated with the increase of the pressure. The line intensity of Ar^＋, on the other hand, reached a maximum value and then decreased along with the pressure. The intensity of the line in an RF discharge also demonstrated a jumping mode and a hysteresis phenomenon with the RF power. When the RF power increased to 400 W, the discharge jumped from the E-mode to the H-mode where the line intensity of Ar atom demonstrated a sudden increase, while the intensity of Ar^＋ ion only changed slightly. If the RF power decreased from a high value, e.g., 1000 W, the discharge would jump from the H-mode back to the E-mode at a power of 300 W. At this time the intensities of Ar and Ar^＋ lines would also decrease sharply. It was also noticed in this paper that the intensity of the ion line depended on the detective location in the chamber, namely at the bottom of the chamber the line was more intense than that in the middle of the chamber, but less intense than at the top, which is considered to be related to the capacitance coupling ability of the ICP plasma in different discharge areas.

感性耦合Ar/O_(2)等离子体放电特性的数值模拟

本文采用流体力学模型对不同腔室材质下的感性耦合Ar/O_(2)等离子体放电特性进行研究.结果表明,由于中性粒子在不同材质表面的黏附系数不同,因而腔室材质对各活性粒子的密度和空间分布产生了显著的影响.依次采用不锈钢、阳极Al_(2)O_(3)和Cu腔室进行放电,发现电子、O^(+)、Ar^(+)、O、O(1D)和Ar_(m)的密度逐渐增大,O_(2)^(+),O^(-),O_(2)和O_(2)(a^(1)Δg)的密度变化趋势相反,各粒子的空间分布特点也有明显差异.在不同腔室中,电子在腔室中心区域的分布是均匀的;O和O_(2)(a^(1)Δg)的密度最大值位于腔室中心,并沿径向逐渐降低;而Ar^(+)和Ar_(m)的密度峰值出现在线圈下方;O^(+),O_(2)^(+)和O(^(1)D)的密度最大值却随着腔室的变化从线圈下方逐渐向腔室中心方向移动;C-离子则被局域在线圈和极板之间一个非常小的区域.最后,讨论了表面反应O→1/2O_(2)的黏附系数对O和O_(2)的影响,发现随着黏附系数的增大,O密度逐渐降低,O_(2)密度变化趋势相反,而且当黏附系数增大到0.5以上时,二者的密度几乎不再受黏附系数的影响.

Global simulation of plasma series resonance effect in radio frequency capacitively coupled Ar/O_(2) plasma

Radio frequency capacitively coupled plasmas(RF CCPs)play a pivotal role in various applications in etching and deposition processes on a microscopic scale in semiconductor manufacturing.In the discharge process,the plasma series resonance(PSR)effect is easily observed in electrically asymmetric and geometrically asymmetric discharges,which could largely influence the power absorption,ionization rate,etc.In this work,the PSR effect arising from geometrically and electrically asymmetric discharge in argon-oxygen mixture gas is mainly investigated by using a plasma equivalent circuit model coupled with a global model.At relatively low pressures,as Ar content(α)increases,the inductance of the bulk is weakened,which leads to a more obvious PSR phenomenon and a higher resonance frequency(ω_(psr)).When the Ar content is fixed,varying the pressure and gap distance could also have different effects on the PSR effect.With the increase of the pressure,the PSR frequency shifts towards the higher order,but in the case of much higher pressure,the PSR oscillation would be strongly damped by frequent electron-neutral collisions.With the increase of the gap distance,the PSR frequency becomes lower.In addition,electrically asymmetric waveforms applied to a geometrically asymmetric chamber may weaken or enhance the asymmetry of the discharge and regulate the PSR effect.In this work,the Ar/O_(2) electronegative mixture gas is introduced in a capacitive discharge to study the PSR effect under geometric asymmetry effect and electrical asymmetry effect,which can provide necessary guidance in laboratory research and current applications.

Influence of Additive Gas on Electrical and Optical Characteristics of Non-equilibrium Atmospheric Pressure Argon Plasma Jet

Electrical and optical properties of an argon plasma jet were characterized. In particular, effects of an additive gas, namely nitrogen or oxygen, on these properties were studied in detail. The plasma jet was found to be of a glow-like discharge, which scarcely changed upon the injection of an additive gas, either directly or through a glass capillary. Optical emission spectroscopy characterization revealed that excited argon atoms were the predominant active species in this plasma jet. Metastable argon atoms were highly quenched, and N2（C3yIu） became the main energy carrier following nitrogen injection. When oxygen was added to the afterglow zone through a glass capillary, no significant quenching effect was observed and the number of oxygen atoms decreased with the increase in oxygen concentration. Finally, to demonstrate an application of this plasma jet, a high-density polyethylene surface was treated with argon, argon/nitrogen, and argon/oxygen plasmas.

Low-pressure-RF plasma modification of UiO-66 and its application in methylene blue adsorption

Defect engineering of metal-organic frameworks has attracted increasing attention in recent years for potential applications in gas storage and catalysis.In this study,defective UiO-66 is obtained by Ar and H_(2)plasma treatments.Compared with the pristine UiO-66,a new aperture with a size of~4 nm appears for a sample with the plasma modification,indicating the formation of mesopores within UiO-66 framework.Characterization results demonstrate that the pore volume,surface area and the number of Lewis and Br?nsted acid sites can be easily tuned by varying the discharge parameters.The adsorption performance of UiO-66 is evaluated for the adsorption of methyl blue.In comparison to the pristine UiO-66 and the sample with H_(2)plasma treatment,the Ar plasma modified sample shows excellent adsorption activity due to the suitable pore size and volume.Equilibrium adsorption capacity as high as 40.6 mg·g^(-1)is achieved for the UiO-66(Ar)sample.

Enhancement of output power density in a modified polytetrafluoroethylene surface using a sequential O_(2)/Ar plasma etching for triboelectric nanogenerator applications

In this work,the surface modification using a two-steps plasma etching has been developed for enhancing energy conversion performance in polytetrafluoroethylene(PTFE)triboelectric nanogenerator(TENG).Enhancing surface area by a powerful O_(2) and Ar bipolar pulse plasma etching without the use of CF_(4) gas has been demonstrated for the first time.TENG with modified surface PTFE using a sequential two-step O_(2)/Ar plasma has a superior power density of 9.9 W·m^(-2),which is almost thirty times higher than that of a pristine PTFE TENG.The synergistic combination of high surface area and charge trapping sites due to chemical bond defects achieved from the use of a sequential O_(2)/Ar plasma gives rise to the intensified triboelectric charge density and the enhancement of power output of PTFE-based TENG.The effects of plasma species and plasma etching sequence on surface morphologies and surface chemical species were investigated by a field emission scanning electron microscopy(FESEM),atomic force microscopy(AFM),and X-ray photoelectron spectroscopy(XPS).The correlation of surface morphology,chemical structure,and TENG performance was elucidated.In addition,the applications of mechanical energy harvesting for lighting,charging capacitors,keyboard sensing and operating a portable calculator were demonstrated.

Atmospheric Pressure Cold Argon/Oxygen Plasma Jet Assisted by Preionization of Syringe Needle Electrode

An atmospheric pressure nonequilibrium argon/oxygen plasma jet assisted by the preionization of syringe needle electrode discharge is reported. With the syringe needle plasma as its pre-ionization source, the hybrid barrier-jet was shown to generate uniform discharge with a lower breakdown voltage and a relatively low gas temperature varying from 390 K to 440 K, even when the vol.% oxygen in argon was up to 6%. Utilizing the actinometry method, the concentration of atomic oxygen was estimated to be about in an orders of magnitude of 10^17 cm^-3. The argon/oxygen plasma jet was then employed to clean out heat transfer oil, with a maximum cleaning rate of 0.1 mm/s achieved.

不同频率驱动下容性耦合Ar等离子体随气压变化的放电特性

讨论了在驱动频率分别为13.56MHz、40.68MHz、94.92MHz和100MHz,功率为40W,气压由3.3~26.6Pa下的容性耦合Ar等离子体的放电特性。利用光谱相对强度法分别诊断了电子激发温度和电子密度。采用粒子模拟和蒙特卡罗碰撞模型(PIC/MCC),模拟了上述实验条件下中心处电子密度和电子能量概率分布(EEPF)。结果表明,在每一个驱动频率下,电子密度均随放电气压的增加而增加,而电子温度则随气压增加而降低。驱动频率为13.56MHz和40.68MHz的电子密度随气压变化趋势几乎一致,而94.92MHz和100MHz的电子温度则随气压变化趋势几乎一致。通过比较EEPF,电子温度随气压的增加有下降的趋势,与光谱诊断结果基本吻合。

Comparison of Structures and Properties between Wool and Ramie Fibers Treated by Atmospheric Pressure Ar and Ar/O_2 Plasma

The technique of atmospheric pressure plasma is of value in textile industry.In this paper,argon(Ar)and argon/oxygen(Ar/O2)atmospheric pressure plasma were used to treat wool and ramie fibers.The structures and properties of treated fibers were investigated by means of SEM,XPS,single fiber tensile tester and so on.The results proved that the effects of plasma treatments depended on structural characteristics of fibers to a great extent,besides conditions of plasma treatment.By atmospheric pressure plasma treatment,wool fiber had significant changes in morphology structure,surface chemical component,mechanic properties and dyeability,while ramie fiber just showed a little change.In additional,Ar/O2 plasma showed more effective action than argon.And at the beginning of treatment,plasma brought about remarkable effects,which did not increase with prolonging of treat time.

Mode transition in dusty micro-plasma driven by pulsed radio-frequency source in C_2H_2/Ar mixture

Physical qualities of dusty plasma in the pulsed radio-frequency C_2H_2/Ar microdischarges are carefully investigated by a one-dimensional hydrodynamic model and aerosol dynamics model.Since the thermophoretic force has a great effect on the nanoparticle density spatial distribution,the neutral gas energy equation is taken into accounted.The effects of pulse parameters（dust ratio,modulation frequency） on the nanoparticle formation and growth process are mainly discussed.The calculation results show that,as the duty ratio increases,the mode transition from the sheath oscillation（a regime） to the secondary electron heating（7 regime） occurred,which is quite different from the conventional pulsed discharge.Moreover,the effect of modulation frequency on the width of sheath and plasma density is analyzed.Compared with the H_2CC^-ions,the modulation frequency effect on the nanoparticles density becomes more prominent.

Reactive Ion Etching of ITO Transparent Electrode of TFT-AMLCD in Ar/CF_4 Plasma

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The Effect of Discharge Power on the Atmospheric Pressure Non-equilibrium Ar/O_2/TiCl_4 Plasma Deposition of TiO_2 Film

Deposition of TiO2 film from atmospheric pressure non-equilibrium Ar/O2/TiCl4 plasma was done to study the effect of discharge power during the film deposition process in this paper. TiO2 films with kinds of morphologies and controlled crystallization were deposited from mixtures of TiCl4 and O2 on quartz substrate by one step process. Scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to analyze the morphology and crystallization of the deposited TiO2 films. It was found that the discharge power played a key role in the morphology and crystallization of the deposited TiO2 film whether the flow of TiCl4 was large or small. When the flow of TiCl4 was large, the deposited TiO2 film was amorphous particles at low discharge power and was multi-crystalline at high discharge power. When the flow of TiCl4 [JP2]was small, the deposited TiO2 film became more compact and the crystallization was enhanced as the discharge power increased . The dependence of the discharge current and the applied voltage with the discharge power indicated that it was a glow discharge. The gas temperature which increases with the discharge power is one of the main causes that affect the morphology and crystallization of the deposited film.

Influence of dielectric materials on uniformity of large-area capacitively coupled plasmas for N_2/Ar discharges

The effect of the dielectric ring on the plasma radial uniformity is numerically investigated in the practical 450-mm capacitively coupled plasma reactor by a two-dimensional self-consistent fluid model. The simulations were performed for N2/Ar discharges at the pressure of 300 Pa, and the frequency of 13.56 MHz. In the practical plasma treatment process,the wafer is always surrounded by a dielectric ring, which is less studied. In this paper, the plasma characteristics are systematically investigated by changing the properties of the dielectric ring, i.e., the relative permittivity, the thickness and the length. The results indicate that the plasma parameters strongly depend on the properties of the dielectric ring. As the ratio of the thickness to the relative permittivity of the dielectric ring increases, the electric field at the wafer edge becomes weaker due to the stronger surface charging effect. This gives rise to the lower N~+ ion density, flux and N atom density at the wafer edge. Thus the homogeneous plasma density is obtained by selecting optimal dielectric ring relative permittivity and thickness. In addition, we also find that the length of the dielectric ring should be as short as possible to avoid the discontinuity of the dielectric materials, and thus obtain the large area uniform plasma.

大气压Ar-NH_(3)混合气体氧化锆介质阻挡放电特性与产物分布

为了更好地调控等离子体氨制氢的效果,从等离子体自身入手,采用较高介电常数(37.1)的氧化锆阻挡介质,通过改变外施电压幅值和NH_(3)掺杂比例,研究大气压Ar-NH_(3)混合气体氛围放电的光电特性,利用光学发射光谱分析了放电产物的种类和代表性产物的分布规律。研究发现,随着外施电压的增加,等离子体沉积的功率逐渐增强,放电电流脉冲数目逐渐增加。较低NH_(3)比例下,亚稳态Ar原子和NH_(3)之间的彭宁反应使得放电图像表现为由汤森发展成辉光放电;而在较高NH_(3)比例下,NH_(3)对放电的淬灭作用逐渐增强,使得放电图像表现为细丝状。放电后缓慢降低电压时,较低NH_(3)比例下的辉光放电保持该放电模式熄灭,而较高NH_(3)比例下的丝状放电以单根放电柱熄灭。随着NH_(3)比例的增加,放电颜色由淡紫色转变为橙黄色,放电发射光强逐渐减弱,NH_(3)对电子的淬灭作用打破了电子产消的平衡模式,大量消耗了激发态氩原子和降低了NH产量,使得产物浓度逐渐降低。研究结果说明,一方面可以利用NH_(3)比例来调控放电模式,另一方面可通过外施电压幅值和NH_(3)比例协同控制放电产物浓度。

大气压双频容性耦合Ar/O_(2)等离子体特性研究

文章利用二维流体模型对双频调制大气压Ar/O_(2)放电特性进行了研究,着重讨论高低频电压、低频频率等不同匹配方式对等离子体参数的影响,并且通过对电子加热模式、电子密度、中性粒子密度、正离子能量以及正离子总通量等分析了大气压Ar/O_(2)放电双频调控机制。结果表明,低频源电压的改变使得电子加热模式由α模式转变为DA/α混合模式,且等离子体密度、正离子总通量及离子能量均随着低频电压的升高而增大,发生了解耦现象。与低频源电压不同,高频源电压和低频源频率对电子加热模式不产生影响。此外,高频源电压对等离子体密度及正离子总通量影响较大,对刻蚀工业中易对材料造成损伤的离子能量影响很小;而低频源频率对工业中影响影响较大的离子能量和离子总通量影响较大,对等离子体密度影响较小,实现了等离子体密度和离子能量的独立控制。

Acetylene/argon mixture plasma to build ultrathin carbon bridge of CF_(x)/C/MnO_(2) for high-rate lithium primary battery

Forming an ultrathin conducting layer on a fluorinated carbon(CFx)surface for reducing severe electrochemical polarization in lithium/fluorinated carbon primary batteries(Li/CF_(x))remains a considerable challenge for achieving batteries with excellent rate capability.Herein,CFxwas modified by using acetylene/argon mixture plasma combined with MnO_(2)particles.The CF_(x)/C/MnO_(2)composite effectively reduced the voltage hysteresis and improved the electrochemical performance of Li/CF_(x).The excellent rate performance of CF_(x)/C/MnO_(2)was due to the high electrochemical activity provided by the atomicscale conductive carbon layer and ultrafine MnO_(2)particles.Compared with pristine CF_(x),the charge transfer resistance of the optimized CF_(x)/C/MnO_(2)decreased from 218.5 to 48.2Ω,the discharge rate increased from 2C to 10C,and the power density increased from 3.11 to 13.44 kW·g^(-1),The intrinsic reason for the enhanced rate performance was attributed to the fact that the ultrathin carbon layer acted as a conductive bridge to reduce the voltage hysteresis at the initial stage of the Li/CF_(x)discharge,and the high electrochemical activity of the ultrafine MnO_(2)particles provided a faster lithium-ion diffusion rate.