Deposition Of Thin Film By Atmospheric Pressure Plasma And Research On The Characterization Of Different Frequency Plasma

In recent decades,due to simple configuration and its ability to dispense expensive vacuum system,atmospheric pressure plasma jet?APPJ?have gathered enormous interest in numerous applications,such as synthesis and modification of materials,biological sterilization,and wastewater treatment.Plasma makes reactive radical more active,which will play a crucial role in alleviating the pressure of the resource shortages.Plasma with high energy promote chemical reaction with polymer materials,and save time effectively.A novel electrode structure extends plume length of plasma jet in the limited spatial scope in comparison with needle-plane electrode,which means miniaturized and portable production.The gas temperature of APPJ is relatively lower,approximately room temperature,which is significant for the treating of thermal sensitive material;and importantly,the density of charge-particle is between 10¹¹-10¹²cm^-3,chemical activity of active species is higher.Compared to single-frequency,dual-frequency?DF?plasma exhibit prominent advantages when radio-frequency?RF?incorporate with low-frequency?LF?plasma.The LF plasma can obtain a longer plasma plume,which expanded plasma discharge area,and it is relatively convenient for large size and complex shape objects.Furthermore,higher electron density of RF plasma indicates that the plasma have a abundance of active radicals,promote the formation of reactive species on the substrate surface,which is the main ingredient of film,makes film deposition more efficient.APPJ is generated by dual-frequency excitation,tube which is composed of 50kHz low-frequency connected to pin electrode and a 33MHz radio frequency applied to copper ring.The stable operating range of?mode discharge generated by dual-frequency can also be expanded,and plasma discharge can be kept stable in a larger voltage range.On the other hand,the centimeter scale plume length and active species of DF plasma jet are helpful in practical plasma application.Organosilicone thin films were deposited using a DF?50kHz/33MHz?plasma jet,precursor HMDSO in the deposition are broken into small radicals in a dual-frequency atmospheric-pressure plasma jet.The emission intensities of reactive species decomposed by HMDSO first increase and followed by a rapid decrease with increasing HMDSO content.Fourier transform infrared spectroscopy?FTIR?and x-ray photoelectron spectroscopy demonstrate that the films are organosilicon with methyl and hydroxyl radical based on Si-O-Si backbone.Based on advantages of dual-frequency atmospheric pressure plasma jet,Organosilicone thin films were favoringly deposited by different double-frequency combination?50kHz/2MHz and 50kHz/33MHz?and more cost-effective in production cost.The highest gas temperature is not more than 200?,the deposited thin film is uniform relatively.Mixed-phase TiO₂ powder is synthesized using atmospheric pressure plasma jet driven by50kHz/100MHz dual-frequency,particle diameter is nanometer scale,its catalytic activity is significantly superior to single frequency case.As mentioned above,excellent performance in material synthesis is attributed to dissimilar radio-frequency sources.Consequently,we feel it necessary to study the characteristics of single radio frequency at the frequencies of 25,64and 100MHz and compare their discharge characteristics.So far most plasma sources were only powered by either LF of several tens of kilohertz or industrial frequency of 13.56MHz.The similar investigation remains largely unexplored between 25¹00MHz.Hence,the effect driving frequency on atmospheric pressure cold plasma is investigated by emission spectra and electric measurements.Contrasting characteristics with driving frequencies at 25,64 and100MHz are prepare for the research of the radio frequency coupling at atmospheric pressure.Motived by the idea,there are still additional work to achieve laboratorial RF source coupled.