Influence of magnetic field on power deposition in high magnetic field helicon experiment

Based on high magnetic field helicon experiment(HMHX), HELIC code was used to study the effect of different magnetic fields on the power deposition under parabolic distribution. This paper is divided into three parts: preliminary calculation, actual discharge experiment and calculation. The results of preliminary calculation show that a magnetic field that is too small or too large cannot produce a good power deposition effect. When the magnetic field strength is 1200 Gs,a better power deposition can be obtained. The actual discharge experiment illustrates that the change of the magnetic field will have a certain influence on the discharge phenomenon. Finally, the results of verification calculation successfully verify the accuracy of the results of preliminary simulation. The results show that in the actual discharge experiment, it can achieve the best deposition effect when the magnetic field is 1185 Gs.

Enhanced antibacterial activity of cotton via silver nanocapsules deposited by atmospheric pressure plasma jet

In this work,the antibacterial activity of cotton containing silver nanocapsules prepared by atmospheric pressure plasma(APP)deposition is investigated.The nanocapsules consist of a shell and a silver nanoparticle(Ag NP)core,where the core is used to bring antibacterial activity,and the shell is utilized to suppress the potential toxicity of Ag NPs.The surface morphology and the elements of the samples are analyzed by scanning electron microscopy(SEM),energy dispersive x-ray and x-ray photoelectron spectroscopy(XPS).The SEM results show that the skin of the cotton fibers will fall off gradually after APP treatment over 3 min,and the XPS results show that the Ag content will rise to 1.6%after APP deposition for 10 min.Furthermore,the antimicrobial activity tests show that the reduction rates of Escherichia coli and Staphylococcus aureus can achieve 100%when the sample is treated for 10 min,which exhibits excellent antibacterial activity.In addition,the UV absorption properties of the cotton will also be correspondingly improved,which brings a broader application prospect for antibacterial cotton.

Impact of back-gate bias on the hysteresis effect in partially depleted SOI MOSFETs

The hysteresis effect in the output characteristics,originating from the floating body effect,has been measured in partially depleted（PD） silicon-on-insulator（SOI） MOSFETs at different back-gate biases.I D hysteresis has been developed to clarify the hysteresis characteristics.The fabricated devices show the positive and negative peaks in the I D hysteresis.The experimental results show that the I D hysteresis is sensitive to the back gate bias in 0.13-渭m PD SOI MOSFETs and does not vary monotonously with the back-gate bias.Based on the steady-state Shockley-Read-Hall（SRH） recombination theory,we have successfully interpreted the impact of the back-gate bias on the hysteresis effect in PD SOI MOSFETs.

Synthesis of SiC/graphene nanosheet composites by helicon wave plasma

We report an approach to the rapid, one-step, preparation of a variety of wide-bandgap silicon carbide/graphene nanosheet(Si C/GNSs) composites by using a high-density helicon wave plasma(HWP) source. The microstructure and morphology of the Si C/GNSs are characterized by using scanning electron microscopy(SEM), Raman spectroscopy, x-ray diffraction(XRD), x-ray photoelectron spectroscopy(XPS), and fluorescence(PL). The nucleation mechanism and the growth model are discussed. The existence of Si C and graphene structure are confirmed by XRD and Raman spectra.The electron excitation temperature is calculated by the intensity ratio method of optical emission spectroscopy. The main peak in the PL test is observed at 420 nm, with a corresponding bandgap of 2.95 e V that indicates the potential for broad application in blue light emission and ultraviolet light emission, field electron emission, and display devices.

Synthesis of Ag-decorated vertical graphene nanosheets and their electrocatalytic efficiencies

Herein we report the successful preparation of silver(Ag)-decorated vertically oriented graphene sheets(Ag/VGs)via helicon wave plasma chemical vapor deposition(HWP-CVD)and radiofrequency plasma magnetron sputtering(RF-PMS).VGs were synthesized in a mixture of argon and methane(Ar/CH_(4))by HWP-CVD and then the Ag nanoparticles on the prepared VGs were modified using the RF-PMS system for different sputtering times and RF power levels.The morphology and structure of the Ag nanoparticles were characterized by scanning electron microscopy and the results revealed that Ag nanoparticles were evenly dispersed on the mesoporous wall of the VGs.X-ray diffraction results showed that the diameter of the Ag particles increased with the increase in Ag loading,and the average size was between 10.49 nm and 25.9 nm,consistent with the transmission electron microscopy results.Ag/VGs were investigated as effective electrocatalysts for use in an alkaline aqueous system.Due to the uniquely ordered and interconnected wall structure of VGs,the area of active sites increased with the Ag loading,giving the Ag/VGs a good performance in the oxygen evolution reaction.The double-layer capacitance(C_(dl))of the Ag/VGs under different Ag loadings were studied,and the results showed that the highest Ag content gave the best C_(dl)(1.04 mF cm^(-2)).Our results show that Ag/VGs are likely to be credible electrocatalytic materials.

Effect of Low-Frequency Power on Etching Characteristics of 6H-SiC in C4F8/Ar Dual-Frequency Capacitively Coupled Plasma

Dry etching of 6H silicon carbide （6H-SiC） wafers in a C4Fs/Ar dual-frequency capacitively coupled plasma （DF-CCP） was investigated. Atomic force microscopy （AFM） and X-ray photoelectron spectroscopy （XPS） were used to measure the SiC surface structure and compositions, respectively. Optical emission spectroscopy （OES） was used to measure the relative concentration of F radicals in the plasma. It was found that the roughness of the etched SiC surface and the etching rate are directly related to the power of low-frequency （LF） source. At lower LF power, a smaller surface roughness and a lower etching rate are obtained due to weak bombardment of low energy ions on the SiC wafers. At higher LF power the etching rate can be efficiently increased, but the surface roughness increases too. Compared with other plasma dry etching methods, the DF-CCP can effectively inhibit CχFγ films＇ deposition, and reduce surface residues.