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[IEEE 2018 China International SAR Symposium (CISS) - Shanghai (2018.10.10-2018.10.12)] 2018 China International SAR Symposium (CISS) - Imaging and Detection of Moving Targetsbased on Spaceborne Video SAR Mode
摘要： Yttrium fluoride (YF3) films were grown on sapphire substrate by a radio frequency magnetron using a commercial ceramic target in a vacuum chamber. The structure, composition, and plasma etching behavior of the films were systematically investigated. The YF3 film was deposited at a working pressure of 5 mTorr and an RF power of 150 W. The substrate-heating temperature was increased from 400 to 700 °C in increments of 100 °C. High-resolution transmission electron microscopy (HRTEM) and X-ray diffraction results confirmed an orthorhombic YF3 structure was obtained at a substrate temperature of 700 °C for 2 h. X-ray photoelectron spectroscopy revealed a strongly fluorinated bond (Y–F bond) on the etched surface of the YF3 films. HRTEM analysis also revealed that the YF3 films became yttrium-oxyfluorinated after exposure to fluorocarbon plasma. The etching depth was three times lower on YF3 film than on Al2O3 plate. These results showed that the YF3 films have excellent erosion resistance properties compared to Al2O3 plates.
关键词： yttrium fluoride,plasma processing equipment,films
更新于2025-09-23 15:22:29
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Effects of material degradation on electrical and optical characteristics of surface dielectric barrier discharge
摘要： In this paper, screen-printed electrodes are asymmetrically fabricated on three different dielectrics (multi-layered polyimide, quartz, and alumina). Supplied with AC power, sustainable surface dielectric barrier discharge (SDBD) plasma is generated in atmospheric pressure. During plasma processing, different changes of material degradation and discharge images are observed. The corresponding electrical and optical characteristics are investigated by optical emission spectra (OES) and Lissajous figure analysis, respectively. It is found that both dielectric degradation and electrode erosion occur on the surface of the polyimide based SDBD device, while there is only electrode erosion for the quartz and alumina based devices, which results in different changes of electrical characteristics. OES calculated results show that with an increase of discharge aging time, electron temperature increases for the polyimide based SDBD device and decreases for quartz and alumina based SDBD devices, while all the gas temperatures of three dielectrics increase with the aging time. Furthermore, compared to vibrational temperature and gas temperature, the distribution of electron temperature is more suitable for evaluating the changes in discharge uniformity during plasma processing.
关键词： electrical characteristics,plasma processing,optical characteristics,surface dielectric barrier discharge,material degradation
更新于2025-09-23 15:21:21
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Precise control of ion and radical production using electron beam generated plasmas
摘要： Precise control over both the relative and absolute ?ux of plasma species as well as their energy deposition at surfaces is critical to enabling the plasma processing of materials with atomic layer precision. In addition to the need for low damage, the complex device structures proposed for next generation nanoelectronics will also require control over radical to ion ratio. Electron beam generated plasmas are capable of generating a wide range of charged particle densities (109–1012 cm?3), while maintaining low electron temperatures (0.1–1.0 eV) and in reactive gas backgrounds, a relatively low radical production rate compared to discharges. These characteristics provide the ability to precisely control both the ion energy at adjacent surfaces and the ion to radical ?ux ratio. The latter capability is realized by coupling an electron beam generated plasma with an auxiliary plasma source designed to promote radical production. In this work, optical emission spectroscopy and Langmuir probe measurements are combined to measure the positive ion and ?uorine atom densities in electron beam generated Ar/SF6 plasmas coupled to a remote, inductively coupled plasma source operating in the same environment. The results indicate that the approach can be used to indepen- dently control the positive ion and F radical densities such that the ion to radical density ratio can be varied over a range of 2–3 orders of magnitude.
关键词： electron beam generated plasmas,ion production,atomic layer precision,radical production,plasma processing
更新于2025-09-23 15:21:01
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Application of Nanostructured Tungsten Fabricated by Helium Plasma Irradiation for Photoinduced Decolorization of Methylene Blue
摘要： The dendritic nanostructure was fabricated on a surface of tungsten plate by helium plasma irradiation. The nanostructure consisting of W metal was partially oxidized to form WO3 on exposure to air, and the resulting surface exhibited a broad photoabsorption in the range from 1 to 5 eV. We examined photoinduced reaction of methylene blue (MB) on the material. It was found that the partially and fully oxidized surface nanostructures were able to promote a decolorization of MB under photoirradiation even with the near-infrared light (< 1:55 eV), whose energy is lower than the band gap of WO3. The reaction rate was varied with the fraction of W and WO3 on the surface layers, that is, the partially oxidized sample promoted the reaction at a higher rate than the fully oxidized one. It is also found that the reaction rate decreased with time, which would be caused by the products accumulation on the surface and the surface oxidation.
关键词： Scanning electron microscopy (SEM),Tungsten oxide,Surface photochemistry,Plasma processing,Nano-wires, quantum wires, and nanotubes,Visible/ultraviolet absorption spectroscopy, X-ray photoelectron spectroscopy
更新于2025-09-23 15:21:01
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Laser-generated plasmas in length scales relevant for thin film growth and processing: simulation and experiment
摘要： In pulsed laser deposition, thin film growth is mediated by a laser-generated plasma, whose properties are critical for controlling the film microstructure. The advent of 2D materials has renewed the interest in how this ablation plasma can be used to manipulate the growth and processing of atomically thin systems. For such purpose, a quantitative understanding of the density, charge state, and kinetic energy of plasma constituents is needed at the location where they contribute to materials processes. Here, we study laser-induced plasmas over expansion distances of several centimeters from the ablation target, which is the relevant length scale for materials growth and modification. The study is enabled by a fast implementation of a laser ablation/plasma expansion model using an adaptive Cartesian mesh solver. Simulation outcomes for KrF excimer laser ablation of Cu are compared with Langmuir probe and optical emission spectroscopy measurements. Simulation predictions for the plasma-shielding threshold, the ionization state of species in the plasma, and the kinetic energy of ions, are in good correspondence with experimental data. For laser fluences of 1–4 J cm?2, the plume is dominated by Cu0, with small concentrations of Cu+ and electrons at the expansion front. Higher laser fluences (e.g. 7 J cm?2) lead to a Cu+ -rich plasma, with a fully ionized leading edge where Cu2+ is the dominant species. In both regimes, simulations indicate the presence of a low-density, high-temperature plasma expansion front with a high degree of ionization that may play a significant role in doping, annealing, and kinetically-driven phase transformations in 2D materials.
关键词： pulsed laser deposition,plasma diagnostics,plasma processing of 2D materials,laser plasma simulation,2D materials,laser ablation,plasma assisted processing
更新于2025-09-23 15:19:57
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[IEEE 2018 IEEE International Interconnect Technology Conference (IITC) - Santa Clara, CA, USA (2018.6.4-2018.6.7)] 2018 IEEE International Interconnect Technology Conference (IITC) - Spray Plasma Processing of Barrier Films Deposited in Air for Improved stability of Flexible Electronic Devices
摘要： We report on submicron organosilicate barrier films produced rapidly in ambient by a scalable spray plasma process for improved solar cell stability. The plasma is at a sufficiently low temperature to be compatible with flexible electronic devices. The thickness of the barrier films is tunable and fully transparent over the visible spectrum. The morphology and density of the barrier are shown to improve with the addition of a fluorine-based precursor. Thin-film perovskite solar cells with submicron coatings exhibited significant improvements in stability when exposed to light, heat, and moisture. X-ray diffraction measurements performed while heating showed the barrier film dramatically slows the formation of PbI2. When deposited on a flexible substrate, the barrier films exhibit no signs of cracking or delamination after 10,000 bending cycles on a 127 μm substrate with a bending radius of 1 cm.
关键词： barrier films,spray plasma processing,flexible electronics,perovskite solar cells,stability
更新于2025-09-10 09:29:36
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Study on the electrical, optical, structural, and morphological properties of highly transparent and conductive AZO thin films prepared near room temperature
摘要： A correlation study between the microstructural, electrical, optical, and morphological properties of the highly transparent and conductive Al-doped ZnO (AZO) films of varying thickness deposited by 3D confined DC magnetron sputtering is reported. Incorporating a high-density plasma environment as indicated by plasma diagnostic it was possible to fabricate AZO films of resistivity as low as ~ 5.2×10-4 Ωcm and the maximum transmittance ~ 89 % with well crystalline structured and smooth morphology at low-temperature. Correlation among the film properties reveals the possibility of filling the Zn atom in the Zn vacancy could be responsible for preparing AZO thin film with improved microstructure and high enrichment of carrier mobility and concentration.
关键词： AZO film,3-D confined magnetron sputtering,Transparent conducting oxide (TCO),Plasma processing
更新于2025-09-10 09:29:36
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A micro-scale plasma spectrometer for space and plasma edge applications (invited)
摘要： A plasma spectrometer design based on advances in lithography and microchip stacking technologies is described. A series of curved plate energy analyzers, with an integrated collimator, is etched into a silicon wafer. Tests of spectrometer elements, the energy analyzer and collimator, were performed with a 5 keV electron beam. The measured collimator transmission and energy selectivity were in good agreement with design targets. A single wafer element could be used as a plasma processing or fusion first wall diagnostic.
关键词： electron beam,microchip stacking,silicon wafer,plasma processing,fusion first wall diagnostic,lithography,plasma spectrometer,collimator,energy analyzer
更新于2025-09-04 15:30:14