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Surface modification via plasma treatment is useful in improving textile-based wound dressing functionality. This study was conducted to optimise the nitrogen plasma exposure time and its effect on the cotton surface (CS) properties at a constant nitrogen flow rate of 20 sccm for 5 to 30 min. The optimisation was done by analysing the alteration in morphology, functional group composition, crystallinity phase, electrokinetic charge, and colour of CS as subjected to nitrogen plasma. CS experienced an etching effect due to the presence of microcracks on its surface, with its electrokinetic charge becoming less negative, ranging from -5.51 to -1.32 mV. Then, the nitrogen functional group was detected on CS ranging from 2.9% to 4.5%, with its whiteness index reduced to 8.67% compared to the pristine cotton. As a result, 20 min was selected as the optimum exposure time for surface treatment because the exposure time of 30 min showed an early sign of degradation, which reduced its crystallinity index by 11.1%. Apparently, activated CS experienced slight changes in its molecular structure without affecting its bulk properties. Thus, the plasma-modified CS is useful in creating a biocompatible wound dressing that can anchor therapeutic biomaterial and improve healing.

Featured Application: In this scientific article, we present an environmentally friendly method for increasing the nitrogen content on the surface of activated carbons, which leads to enhanced CO2 adsorption of these carbons. The commercially available activated carbon was modified using barrier and spark discharge low-temperature nitrogen plasma treatment. The samples were investigated using nitrogen sorption at a temperature of −196 °C, XRD, SEM, and FTIR methods, and elemental analysis. The nitrogen content on the surface was increased, but other properties, such as specific surface area, total pore volume, pseudocrystallite height, and pseudocrystallite width, remained unchanged. The activated carbons after nitrogen plasma treatment indicated higher CO2 adsorption than the pristine ones. Since the investigated materials only differed in their nitrogen content, it has been unequivocally demonstrated that the increased presence of nitrogen is responsible for the enhanced adsorption of CO2. The low-temperature nitrogen plasma treatment of activated carbon is a promising method for enhancing CO2 capture. [ABSTRACT FROM AUTHOR]

Surface modification via plasma treatment is useful in improving textilebased wound dressing functionality. This study was conducted to optimise the nitrogen plasma exposure time and its effect on the cotton surface (CS) properties at a constant nitrogen flow rate of 20 sccm for 5 to 30 min. The optimisation was done by analysing the alteration in morphology, functional group composition, crystallinity phase, electrokinetic potential, and colour of CS as subjected to nitrogen plasma. CS experienced an etching effect due to the presence of microcracks on its surface, with its electrokinetic potential becoming less negative, ranging from -5.51 to -8.05 mV. Then, the nitrogen functional group was detected on CS ranging from 2.9% to 4.5%, with its whiteness index reduced to 8.67% compared to the pristine cotton. As a result, 20 min was selected as the optimum exposure time for surface treatment. An exposure time of 30 min showed an early sign of degradation, which reduced its crystallinity index by 11.1%. Apparently, the CS is activated as exposed to the nitrogen plasma and experiences slight changes in its molecular structure without affecting its bulk properties. [ABSTRACT FROM AUTHOR]

The active-particle number density is a key parameter for plasma material processing, space propulsion, and plasma-assisted combustion. The traditional actinometry method focuses on measuring the density of the atoms in the ground state, but there is a lack of an effective optical emission spectroscopy method to measure intra-shell excited-state densities. The latter atoms have chemical selectivity and higher energy, and they can easily change the material morphology as well as the ionization and combustion paths. In this work, we present a novel state-resolved actinometry (SRA) method, supported by a krypton line-ratio method for the electron temperature and density, to measure the number densities of nitrogen atoms in the ground and intra-shell excited states. The SRA method is based on a collisional-radiative model, considering the kinetics of atomic nitrogen and krypton including their excited states. The densities measured by our method are compared with those obtained from a dissociative model in a miniature electron cyclotron resonance (ECR) plasma source. Furthermore, the saturation effect, in which the electron density remains constant due to the microwave propagation in an ECR plasma once the power reaches a certain value, is used to verify the electron density measured by the line-ratio method. An ionization balance model is also presented to examine the measured electron temperature. All the values obtained with the different methods are in good agreement with each other, and hence a set of verified rate coefficient data used in our method can be provided. A novel concept, the 'excited-state system', is presented to quickly build an optical diagnostic method based on the analysis of quantum number propensity and selection rules. [ABSTRACT FROM AUTHOR]

This study reports on the influence of nitrogen plasma exposure of H‐diamond (100) on the adsorption of adventitious oxygen, nitrogen bonding, and thermal stability studied by X‐ray photoelectron spectroscopy. The nitrogen‐plasma exposures include microwave (MW) and radio frequency (RF) (at pressures: 3 × 10−2 (damaging) and 7 × 10−2 Torr (nondamaging)) nitrogen plasmas. The largest amount of oxygen ambient adsorption occurs on the damaging RF(N2) (O = 2.8 at%) exposed surface, whereas for MW(N2) (O = 0.8 at%) and nondamaging RF(N2) (O = 1.3 at%) exposed surfaces, a lower oxygen concentration is observed. Also, the highest level of structural damage to the upper atomic layers of the diamond is induced by exposure to the damaging RF(N2), followed by nondamaging RF(N2) and MW(N2). Thus, the near‐surface damage induced by the plasma interaction promotes adventitious oxygen adsorption (in various bonding configurations, including COx and C–NOx). For ambient‐exposed MW(N2)‐processed surface, nitrogen is adsorbed mainly in C–N/C=N state. Whereas for ambient‐exposed nondamaging‐ and damaging RF(N2)‐treated surfaces, nitrogen is bonded in mixed C–N/C=N and C≡N states alongside a small C–NOx component depending on the degree of surface defects. The damaging RF(N2)‐exposed surface exhibits a lower oxygen and nitrogen thermal stability than the other cases. [ABSTRACT FROM AUTHOR]

The commercially available activated carbon was modified using barrier and spark discharge low-temperature nitrogen plasma treatment. The samples were investigated using nitrogen sorption at a temperature of −196 °C, XRD, SEM, and FTIR methods, and elemental analysis. The nitrogen content on the surface was increased, but other properties, such as specific surface area, total pore volume, pseudocrystallite height, and pseudocrystallite width, remained unchanged. The activated carbons after nitrogen plasma treatment indicated higher CO2 adsorption than the pristine ones. Since the investigated materials only differed in their nitrogen content, it has been unequivocally demonstrated that the increased presence of nitrogen is responsible for the enhanced adsorption of CO2. The low-temperature nitrogen plasma treatment of activated carbon is a promising method for enhancing CO2 capture.

The effect of cooling conditions in the plasma-assisted molecular-beam epitaxy growth on the structural and optical properties of InGaN nanostructures is studied. It is shown that cooling of the samples without nitrogen plasma contributes to the suppression of phase separation in InGaN nanostructures. The integrated intensity of photoluminescence from these nanostructures increased by a factor of 2. [ABSTRACT FROM AUTHOR]

The formation of the electron energy distribution function (EEDF) and phase flows of electrons in the plasma of a positive column of a glow discharge in a model gas with strong vibrational excitation, similar to molecular nitrogen, is analyzed in a wide pressure range. It is found that the traditional local approximation for calculating the EEDF can only be used at medium gas pressures, when the characteristic size of the plasma volume exceeds electron energy relaxation length in the entire range of electron energies. With a decrease in gas pressure, a new phenomenon is discovered—merging the phase flow streamlines into a single line on the coordinate-energy phase plane in the energy region of the of vibrational excitation threshold. It is shown that the combination of a strong electron sink at the threshold of vibrational excitation and the deceleration of electrons in an ambipolar field lead to a practical 'vanishing' of the component of the phase electron flux upward in energy. As a result, the streamlines of electron phase flow approach to some approximately straight line of constant kinetic energy close to the threshold energy of vibrational excitation. The formation of this feature on the phase plane correlates with the predominant escape to the walls of electrons with kinetic energy equal to the threshold of vibrational excitation. [ABSTRACT FROM AUTHOR]

A nanosecond atmospheric pressure plasma jet operated in pure nitrogen is studied by spatially and temporally resolved optical emission spectroscopy complementing the companion paper (Kuhfeld et al 2023 Plasma Sources Sci. Technol. 32 084001), where the discharge is investigated by means of Particle-in-Cell/Monte Carlo collisions (PIC/MCC) simulations and fluid models. Two temporal phases of the evolution of the discharge are identified: a fast breakdown and a quasi-DC phase. It is shown that during the breakdown phase several ionization waves develop, while after the breakdown the discharge has a structure similar to DC glow discharges, in agreement with the modeling predictions. The results of the measurements of the spatial-temporal dynamics of the light emission are compared with the distribution of densities of the N 2 + ( B 2 Σ u +) and N 2 ( C 3 Π u) states reconstructed from the PIC/MCC simulations. A good agreement is demonstrated. [ABSTRACT FROM AUTHOR]

The present study investigates the physics of a nanosecond-pulsed microplasma operated at a pressure of 200 mbar with the help of a particle-in-cell simulation with Monte Carlo treatment of collision (PIC/MCC) and (semi-)analytical models. The discharge is ignited in a 1 mm gap between two parallel molybdenum electrodes by applying a voltage in the kV-range for several tens to hundreds of nanoseconds. A PIC/MCC simulation code is developed in order to describe the experiment performed under identical conditions. The simulation includes the external electrical circuit to perform ab-initio calculations of the complete experimental setup. Notable features of the PIC/MCC are (i) the adjustment of super-particle weights to reduce the computational load during drastic changes of the plasma density, which reaches values up to a few 10 19 m − 3 , and (ii) the inclusion of dissociative recombination of the N 4 + ions, which is the key loss process for the charge carriers in the plasma bulk regions. The current and voltage waveforms obtained from the simulation are compared to the experimentally measured ones and good agreement is found. After ignition, the discharge establishes a quasi-steady state exhibiting spatial features similar to a conventional DC glow discharge. Using the PIC/MCC results, reasonable approximations are identified, which allow the development of various analytical fluid models for the individual plasma regions. These models are able to reproduce the key features of the discharge in agreement with the PIC/MCC results. The simplified models for the different discharge regions can be combined to describe the global behaviour of the discharge and—in a next step—might be used to develop computationally efficient global chemistry models that account for the different power dissipation mechanisms along the discharge gap. [ABSTRACT FROM AUTHOR]

This study discussed the effect of oxygen impurity in the inlet gas of a nitrogen atmospheric pressure plasma jet (APPJ). A numerical model that takes into account the fluid dynamics, heat transfer, mass transfer, diffusion, and chemical reactions was developed to simulate the nitrogen APPJ. Further, a DC nitrogen APPJ experiment was performed to verify the plasma temperature characteristics on the treated surface. The plasma temperature decreased with an increase in the oxygen impurity. Moreover, the oxygen impurity influenced the related excited and neutral species. Specifically, with added oxygen impurity, N-related species decreased whereas O- and NOx-related species increased. Because the excited state species constitutes the most important reactant in APPJ treatment, this study could serve as a reference for the adjustment of a nitrogen APPJ. [ABSTRACT FROM AUTHOR]

Hydroxyethyl cellulose (HEC) doped with 3 wt% erbium nitrate film was prepared by casting from solution. The effect of plasma treatment on optical properties of composite film was investigated. The optical absorbance was measured in the wavelength region of 200–800 nm. . Electronic transition was proved to be direct allowed for pristine and plasma treated film. Tauc’s plots were used to determine the optical band gap (Eopt) of the samples under study. The energy gap was 5.30 eV for untreated composite film and the treated samples at 10, 20 and 30 min have lower values of optical band gap, 5.22, 5.20 and 4.90 eV respectively. It was also found that the Urbach energy values (Ee) were decreased under different plasma treatment times. It begins with 1.46 eV for untreated sample till it reaches 0.72 eV for 30-minute treated sample. Wemple–DiDomenico model parameters such as, oscillator energy, dispersion energy and zero-frequency refractive index values were calculated and their variations with plasma were studied. The color parameters for composite film are noticeably affected under plasma treatment.

Solid‐state batteries (SSBs) that use solid electrolytes instead of flammable liquid electrolytes have the potential to generate higher specific capacity and offer better safety. Magnesium (Mg) based SSBs with Mg metal anodes are considered to be one of the most promising energy storage candidates, because it gives high theoretical volumetric capacities of 3830 mAh cm−3. Here, we demonstrate an atomic layer deposition (ALD) process with a double nitrogen plasma process that successfully produces nitrogen‐incorporated magnesium phosphorus oxynitride (MgPON) solid‐state electrolyte (SSE) thin films at a low deposition temperature of 125 °C. The ALD MgPON SSEs exhibit an ionic conductivity of 0.36 and 1.2 μS cm−1 at 450 and 500 °C, respectively. The proposed ALD strategy shows the ability of conformal deposition nitrogen‐doped SSEs on pattered substrates and is attractive for using nitride ion‐conducing films as protective or wetting interlayers in solid‐state Mg and Li batteries. [ABSTRACT FROM AUTHOR]

Few-layer violet phosphorus (VP) shows excellent potential in optoelectronic applications due to its unique in-plane anisotropy and high mobility. However, the poor air stability of VP severely limits its practical applications. This article reports highly air-stable VP obtained by a two-step nitrogen plasma treatment where the nitrogen volume flow rate is controlled to coordinate physical etching and chemical doping. Specially, this plasma process can remove partial oxidations formed on the VP surface with barely etching to the intrinsic VP surface but efficiently incorporates nitrogen into VP, resulting in surface nitrogen-doped VP (N-VP) nanosheets with atomically smooth surfaces that exhibit excellent air stability. Atomic force microscopy images show that the N-VP nanosheet, nearing a monolayer thickness, maintained its surface morphology and flatness unchanged in ambient air for over 60 days. The improved stability of N-VP can be partly due to its atomically smooth surface, which reduces the number of active or oxidation sites. Further elucidation was made by density functional theory calculations, showing that this ultrastability may intrinsically be attributed to repairing P vacancies by N dopants. This research provides a feasible strategy for significantly enhancing the durability of VP.

In this work, we demonstrate the effectiveness of nitrogen plasma treatment on the formation of low-resistive source/drain (S/D) in self-aligned (SA) oxide thin-film transistors (TFTs) using a high-mobility oxide semiconductor (OS), In-Ga-Zn-Sn-O (IGZTO). The nitrogen plasma treatment was more effective at reducing the sheet resistance ( ${R} _{\mathrm{ sheet}}$ ) of IGZTO films than the commonly used argon plasma treatment. Furthermore, ${R} _{\mathrm{ sheet}}$ for nitrogen-plasma-treated IGZTO films remained low, even when the RF power and radiation time during the plasma treatment were increased when the minimum ${R} _{\mathrm{ sheet}}$ was achieved. The same trends were also observed in OS films with different compositions, such as In-Ga-Zn-O and In-Sn-Zn-O. These results indicate that nitrogen plasma treatment is effective for achieving a reduction of ${R} _{\mathrm{ sheet}}$ for various OS films with a wide process window regarding plasma processing parameters. The advantages could be attributed to the smaller sputtering effect on the OS films due to the lower mass of nitrogen ions than argon ions, which was verified by X-ray reflectivity and X-ray photoelectron spectroscopy analyses. For further validation, SA IGZTO TFTs with a channel length ( ${L}$ ) of 3 to 100 $\mu \text{m}$ were fabricated with nitrogen or argon plasma treatment. The width-normalized parasitic SD resistance ( $R_{\mathrm{ SD}} {W}$ ) with the nitrogen plasma treatment was determined to be 11.3 $\Omega \cdot $ cm, which was ca. 40% lower than that with the argon plasma treatment. This improvement in $R_{\mathrm{ SD}} {W}$ resulted in higher mobility ( $\mu $ ) in the nitrogen-plasma-treated SA IGZTO TFTs. A nitrogen-plasma-treated SA IGZTO TFT with $L=10\,\,\mu \text{m}$ exhibited a high $\mu $ of 27.2 cm2/Vs.

High temperature thermal plasma gasification can treat non-homogeneous waste at increased conversion efficiency, compared to conventional gasification. A novel nitrogen plasma technology demonstration system is presented. The system can convert 20 kg/h of biomass to synthesis gas and is constructed inside a shipping container, which makes it mobile and suitable for application in remote rural areas of developing countries. An Aspen Plus model of the plasma gasification reactor was developed to enable energy and exergy analysis. The model gave good predictions of the real synthesis gas composition obtained during experimental runs. Simple gas and steam power cycles were also modelled to assess the feasibility of the system producing its own power. Based on typical composition of wood, it was found that the plasma torch power requirement is 20.7 kW. This amount of power can be generated using an open gas turbine cycle with compressor pressure ratio of 5 and turbine inlet temperature of 1007 °C. For a combined cycle case, using steam at 8 bar and 400 °C in a steam cycle, 14.6 kW of excess power becomes available. Alternatively, 68 kg/h of steam can be delivered, in addition to satisfying the torch requirement. • Plasma gasification can treat non-homogeneous waste at high conversion efficiency. • Plasma gasification requires significant power for the plasma torch. • A containerized nitrogen plasma system for small scale waste processing is presented. • The plasma torch power requirement can be satisfied by converting the syngas to power. • Exergy analysis identified non-avoidable and avoidable losses for future improvement. [ABSTRACT FROM AUTHOR]

Outstanding wide‐bandgap semiconductor material such as gallium nitride (GaN) has been extensively utilized in power electronics, radiofrequency amplifiers, and harsh environment devices. Due to its quantum confinement effect in enabling desired deep‐ultraviolet emission, excitonic impact, and electronic transport features, 2D or ultrathin quasi‐2D GaN semiconductors have been one of the most remarkable candidates for future growth of microelectronic devices. Here, for the first time, the authors report a large area, wide bandgap, and room‐temperature quasi‐2D GaN synthesis and printing strategy through introducing the plasma medicated liquid metal gallium surface‐confined nitridation reaction mechanism. The developed direct fabrication and compositional process is consistent with various electronics manufacturing approaches and thus opens an easy going way for cost‐effective growth of the third‐generation semiconductor. In particular, the fully printed field‐effect transistors relying on the GaN thus made show p‐type switching with an on/off ratio greater than 105, maximum field‐effect hole mobility of 53 cm2 V−1 s−1, and a small sub‐threshold swing. As demonstrated, the present method allows to produce at room temperature the GaN with thickness spanning from 1 nanometer to nanometers. This basic method can be further extended, generalized, and utilized for making various electronic and photoelectronic devices in the coming time. [ABSTRACT FROM AUTHOR]

The challenge of combining MEC-MIP OES arises from the limited number of emission lines available in this analytical technique. For the MEC-MIP OES optimization, the emission line wavelengths, sample dilution, proportion sample:standard for preparing MEC solutions, and nebulizer gas flow rate were studied. Then, the use of multi-energy calibration (MEC) and microwave-induced plasma optical emission spectrometry (MIP OES) was proposed as an alternative method for the determination of essential elements (Ca, K, Mg, Mn, and Na) in cocoa. In the optimized conditions, the method presented adequate analytical performance, with recoveries of 94–104 % and relative standard deviations lower than 5 %, showing adequate precision. The limits of detection (mg kg−1) were 12 for Ca, 2 for K, 3 for Mg, 3 for Mn, and 6 for Na. The proposed method was applied to analyze cocoa samples cultivated in Brazil and Ecuador after acid decomposition. The results were in the range (mg kg−1) of 409–1530 for Ca, 5520-13300 for K, 1460–3210 for Mg, 16–34 for Mn, and 28–61 for Na. Samples cultivated in Ecuador presented higher metal concentrations than the Brazilian samples. The proposed procedure was an easy and reliable approach for determining metals in cocoa samples, enabling multi-elemental determination with a lower cost and simplified calibration to be applied in routine applications. [Display omitted] • MEC-MIP OES method was proposed for the determination of metals in cocoa. • Mn, Na, Ca, K, and Mg can be determined by MEC-MIP OES in cocoa. • MEC-MIP OES method is cheaper than conventional methods and precise (RSD < 4 %). [ABSTRACT FROM AUTHOR]

• Oxygen adsorption from the ambient depends on the structural defect density on the Di(111) surface caused by the nitrogen plasma interaction. • Nitrogen and oxygen exist in mostly a single bonding configuration on low damage surface. • Hydrogen co-adsorbs alongside N and O onto the Di(111) surfaces upon nitrogen plasma exposure. We report on the chemical composition, bonding, and in-vacuum thermal stability (up to 1000 °C) of nitrogen plasma terminated H-Diamond(111) (H-Di(111)) surfaces followed by ambient exposure. The nitrogen-plasma exposures include radio frequency (RF) (at pressure: 3 × 10−2 (damaging) and 7 × 10−2 Torr (non-damaging)) and microwave (MW) nitrogen plasmas and studied by X-ray photoelectron spectroscopy (XPS) and high resolution electron energy loss spectroscopy (HREELS). The largest nitrogen intake was observed upon exposure to RF(N 2) damaging plasma, followed by MW(N 2) and non-damaging RF(N 2) plasmas. A similar trend follows the adsorption of adventitious oxygen. The XPS analysis shows that most of the adventitious oxygen is adsorbed in a CO x configuration upon nitride surfaces exposure to ambient conditions. However, upon high temperature annealing of the damaging RF(N 2) plasma exposed surface, some NO x (species) were detected by XPS. From the HREELS analysis, the hydrogen adsorbed on the H-Di(111) is not fully removed by exposure to the different nitrogen plasmas. These measurements show that NH(ads) species are formed on the surface and are desorbed upon vacuum annealing in the 500–700 °C range. This study may be of importance in all ex-situ applications influenced by the near-surface physicochemical and electronic properties of nitrogen-terminated H-Di(111) surfaces. [Display omitted] [ABSTRACT FROM AUTHOR]

Copper (Cu) removal efficiency is a key parameter in the processing of Cu-based electronic devices. Herein, a nitrogen plasma-assisted picosecond (ps) laser process for Cu removal is presented. Based on the cleaning and activation effect of nitrogen plasma on the surface of Cu film in ps-laser ablation, the removal efficiency can be significantly improved. Theoretically, the interaction mechanism between Cu and the ps-laser under the action of the plasma flow field is investigated by the dual temperature model (TTM) and finite element analysis (FEA). Meanwhile, the experimental results show that the angle of the plasma flow significantly affects the laser ablation of Cu. Small-angle plasma helps to improve the ps-laser processing precision of Cu, while large-angle plasma can effectively improve the ps-laser processing efficiency of Cu. Under the laser fluence of 2.69 J/cm2, the removal depth of the Cu film by a 30° plasma-assisted ps-laser is 148% higher than that by the non-plasma-assisted ps-laser, which indicates the application potential of nitrogen plasma in improving the laser ablation process. [ABSTRACT FROM AUTHOR]

In this work, formation of nitrogen-containing TiOх and СuxO/TiOх coatings, as well as their structure-related phase composition, elemental composition, and hydrophilicity have been studied. The coatings have been obtained by treating titanium films in a flow of low-temperature nitrogen plasma in open atmosphere using a copper anode. It has been shown that the rate of copper anode erosion and treatment conditions directly affect the synthesis and structure-related phase composition, elemental composition, and hydrophilicity of the coatings. These results indicate the potential of plasma technology for the formation of composite coatings with desired characteristics through variations in the material and erosion rate of an anode. [ABSTRACT FROM AUTHOR]

Three‐dimensional porous scaffolds have the potential to revolutionize a number of fields, including stem cell research, biomedical implants, tissue engineering, and regeneration, as well as energy technologies, filtration, and sensing. The ability to precisely engineer their surface properties is paramount to successful and enduring application. Plasma treatments promise to deliver homogeneous surfaces with tailored characteristics while generating few by‐products and not relying on the diffusion of liquids into a porous network. However, forming plasma inside complex interconnected pores is a significant challenge and requires much parameter fine‐tuning. This study uses numerical modeling to investigate key parameters which affect plasma breakdown and makes practical recommendations for achieving treatment homogeneity. We consider a dielectric barrier discharge (DBD) system, where nitrogen gas flows through a glass tube containing a porous scaffold, which is surrounded by a cylindrical electrode, with ground electrodes at either end of the tube. The parameters investigated include the scaffolds' pore size and porosity as well as electrode size and position. The results showed that homogeneous treatment is achieved by avoiding alternative breakdown pathways such as a poor seal between the scaffold and the glass containment tube, using a narrow supply electrode centered at the scaffold, and positioning ground electrodes as close as possible to the supply electrode without arcing. This strategy maximizes the electric field strength at a given voltage, allowing for higher pressures to be used, which in turn give a more homogeneous mean free path inside the pores. [ABSTRACT FROM AUTHOR]

Hydroxyethyl cellulose (HEC) doped with 3 wt% erbium nitrate film was prepared by casting from solution. The effect of plasma treatment on optical properties of composite film was investigated. The optical absorbance was measured in the wavelength region of 200–800 nm.. Electronic transition was proved to be direct allowed for pristine and plasma treated film. Tauc's plots were used to determine the optical band gap (E opt) of the samples under study. The energy gap was 5.30 eV for untreated composite film and the treated samples at 10, 20 and 30 min have lower values of optical band gap, 5.22, 5.20 and 4.90 eV respectively. It was also found that the Urbach energy values (E e) were decreased under different plasma treatment times. It begins with 1.46 eV for untreated sample till it reaches 0.72 eV for 30-minute treated sample. Wemple–DiDomenico model parameters such as, oscillator energy, dispersion energy and zero-frequency refractive index values were calculated and their variations with plasma were studied. The color parameters for composite film are noticeably affected under plasma treatment. [ABSTRACT FROM AUTHOR]

Herein, the nitrogen plasma treatment with different time irradiation (0, 90, 120, and 150 min) is used to tune the structure, optical, and magnetic properties of nanostructured NiMoO4 NMO NPs. The XRD patterns revealed that the crystallinity of NMO samples increases with an increase in the N2 plasma exposure time. The notable reduce in this peak' intensity for the sample at dose of 120 min may be attributed to the energy dissipated in the defect generation. Also, the crystallite size for NMO samples was found in the range (23.9–26.7) nm. Further, EPR is used to evaluate the impact of the treatment duration on the oxygen vacancy density. The total number of spins rises as plasma irradiation duration increases, revealing that the NMO NPs can be used as a dosimeter for plasma irradiation. The optical bandgap ranged from 2.92 eV to 3.24 eV as the N2 plasma treatment duration changed. The saturation magnetization was enhanced with the rise of plasma treatment time. Furthermore, the Hc increases from 16.67 G for untreated NMO NPs to 128.41 G for N2 plasma-treated NMO NPs for 150 min. The resulted optical and magnetic properties of N2 plasma-treated NMO NPs make it candidate material for photocatalysis applications. [ABSTRACT FROM AUTHOR]

In this work, the effect of different modes of lime charging and plasma exposure on the removal of impurities from the pig iron melt was studied. Pig iron melt was prepared in a 2 kg capacity electric arc furnace. Fluxed direct reduced iron (DRI) (~ 80%Reduced (R) and 8-Basicity (CaO/SiO2) pellets were taken into consideration in this study. The liquid melt was exposed to different plasma (air, nitrogen and hydrogen) environments for reaction times of 15 min. In the current study, nitrogen is used to provide neutral and hydrogen is used to provide a reducing environment on the top of the melt inside the furnace. Lime was charged in the powder form as pure and in the form of flux as reduced pellets (fluxed DRI). Results showed that phosphorous removal is negligible in all the cases while sulphur removed a maximum of ~ 91% in the case of nitrogen and hydrogen plasma and lime charging as powder. [ABSTRACT FROM AUTHOR]

This study discussed the effect of oxygen impurity in the inlet gas of a nitrogen atmospheric pressure plasma jet (APPJ). A numerical model that takes into account the fluid dynamics, heat transfer, mass transfer, diffusion, and chemical reactions was developed to simulate the nitrogen APPJ. Further, a DC nitrogen APPJ experiment was performed to verify the plasma temperature characteristics on the treated surface. The plasma temperature decreased with an increase in the oxygen impurity. Moreover, the oxygen impurity influenced the related excited and neutral species. Specifically, with added oxygen impurity, N-related species decreased whereas O- and NOx-related species increased. Because the excited state species constitutes the most important reactant in APPJ treatment, this study could serve as a reference for the adjustment of a nitrogen APPJ.

[Display omitted] • A model for energy-dependent XPS for depth profiling of chemical bonding. • N-Terminated diamonds obtained by Microwave Plasma show no sp2 defects. • A ∼5 % coverage of graphene-like islands is present atop the diamond surface. • The energy level of N surface states is determined within the diamond bandgap. • The high energy of the unoccupied surface states could help to stabilize NV- centers. Nitrogen-terminated diamonds hold promise for stabilizing near-surface NV− centers, which is essential for reliable quantum sensing. Among various surface preparation methods, microwave (MW) nitrogen plasma, known for its minimal surface damage, appears as the most effective choice. In this investigation, we explore the nature of nitrogen bonding of polycrystalline diamond (PCD) surfaces exposed to MW nitrogen plasma using X-ray Photoelectron Spectroscopy (XPS) depth profiling and Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy at the C K - and N K -edges. XPS depth profiling with atomic resolution, achieved by varying the probing photon energy using synchrotron radiation and supported by a physical model considering the associated inelastic mean free path, suggests a surface of almost fully saturated nitrogen in two main bonding configurations of similar contribution and a low coverage of ∼5 % of graphene-like islands residing atop the nitrogen-terminated diamond surface. The thermal stability of these surface groups is monitored by in situ annealing up to 700 °C. The depth profiles reveal that nitrogen atoms do not diffuse in the diamond crystal, resulting in excellent diamond crystallinity in the first atomic planes below the surface. C K -edge NEXAFS analysis reveals the position of unoccupied surface states within the diamond bandgap, opening new perspective on the stabilization of near-surface NV− centers. [ABSTRACT FROM AUTHOR]

Polyacrylonitrile (PAN)-based carbon felt was subjected to N2-plasma treatment to increase the heteroatom defects and reactive edge sites as a method to increase the performance in vanadium redox flow batteries (VRFBs). N-doping in the felt was mainly in the form of pyrrolic and pyridinic nitrogen. Even though the amount of oxygen functional groups on the N2-plasma-treated sample was very low, the felt showed enhanced electrochemical performance for both V3+/V2+ as well as V5+/V4+ redox reactions. The result is highly significant as the pristine electrode with the same amount of oxygen functional groups showed significantly less activity for the V3+/V2+ redox reaction. Overall, the single-flow cell experiments with N2-plasma-treated felt showed superior performance compared to the pristine sample. Therefore, the enhanced performance observed for the N2-plasma-treated sample should be attributed to the increase in defects and edge sites. Thus, from the present study, it can be concluded that an alternate way to increase the performance of the VRFBs is to introduce specific defects such as N-doping/substitution or to increase the edge sites. In other words, defects induced in the carbon felt such as heteroatom doping are as beneficial as the presence of oxygen functional groups for the improved performance of VRFBs. Therefore, for an optimum performance of VRFBs, defects such as N-substitution as well as oxygen functionality should be tuned.

The article investigates a low-temperature plasma of the magnetron discharge of a device used for the synthesis of dielectric films by reactive cathode sputtering. The aim of the study is to determine the temperature characteristics of plasma particles and a sputtered substance, as well as the mechanism for the formation of a chemical bond between sputtered atoms and active gas molecules. A study of the composition and energy parameters of the plasma, as well as the chemical composition of the particles obtained by sputtering, was carried out by a spectroscopic method. The quantitative composition was determined by a mass spectrometer to determine the composition of the sputtered particles.

Background: Skin laxity is one of the defining characteristics of aging and can be the result of various factors including intrinsic aging, genetics, diet, stress, lifestyle, sun exposure, weight fluctuations, and smoking. Recent reports suggest the ability of subdermal energy application to reduce skin laxity. Thermal energy can be delivered using different devices including lasers, radiofrequency (RF) monopolar and bipolar devices, and plasma/RF devices. Plasma‐based energy platforms generate a plasma gas, allowing heat to be applied to the tissue. This study focused on the evaluation of thermal effect of plasma/RF compared to a monopolar RF device applied percutaneously to the subdermis and connective fibroseptal network in a porcine model. Methods: The subdermal application of energy was conducted using a plasma/RF system and a monopolar RF system. Both low and high energy/temperature settings were evaluated in dynamic and stationary modes. Histomorphometry was used to determine the depth of thermal effect associated with each treatment setting. Results: Both dermis and fibroseptal network tissue exhibited the presence of microscopically thermally treated zones. There were no significant differences in average and maximum depths of thermal effect between the different handpieces and electrosurgical systems used for all treatment settings. Conclusions: No significant differences in the thermal effect between plasma/RF and monopolar RF systems were observed, suggesting that plasma/RF systems can be safely used for the percutaneous application of energy in the subcutaneous space. [ABSTRACT FROM AUTHOR]

Copper (Cu) removal efficiency is a key parameter in the processing of Cu-based electronic devices. Herein, a nitrogen plasma-assisted picosecond (ps) laser process for Cu removal is presented. Based on the cleaning and activation effect of nitrogen plasma on the surface of Cu film in ps-laser ablation, the removal efficiency can be significantly improved. Theoretically, the interaction mechanism between Cu and the ps-laser under the action of the plasma flow field is investigated by the dual temperature model (TTM) and finite element analysis (FEA). Meanwhile, the experimental results show that the angle of the plasma flow significantly affects the laser ablation of Cu. Small-angle plasma helps to improve the ps-laser processing precision of Cu, while large-angle plasma can effectively improve the ps-laser processing efficiency of Cu. Under the laser fluence of 2.69 J/cm2, the removal depth of the Cu film by a 30° plasma-assisted ps-laser is 148% higher than that by the non-plasma-assisted ps-laser, which indicates the application potential of nitrogen plasma in improving the laser ablation process.

p-type cupric oxide (p-CuO) thin films on n-type silicon substrates were grown to make p-CuO/n-Si heterojunctions. The CuO deposition on Si was carried out using radio frequency (RF) magnetron sputtering followed by rapid thermal annealing at 350°C. Plasma nitridation was used to incorporate nitrogen (N) for improving the electrical conductivity of the CuO thin films. The crystalline structure and surface composition of RF-sputtered CuO were characterized by x-ray diffraction and x-ray photoelectron spectroscopy. It was observed that the introduction of nitrogen in CuO improves the photovoltaic properties, such as the open-circuit voltage, short circuit current, and the photocurrent of the p-CuO-n-Si heterojunction. [ABSTRACT FROM AUTHOR]

The strategic design of catalysts for the oxygen evolution reaction (OER) is crucial in tackling the substantial energy demands associated with hydrogen production in electrolytic water splitting. Despite extensive research on birnessite (δ-MnO 2 ) manganese oxides to enhance catalytic activity by modulating Mn 3+ species, the ongoing challenge is to simultaneously stabilize Mn 3+ while improving overall activity. Herein, oxygen (O) vacancies and nitrogen (N) doping have been simultaneously introduced into the MnO 2 through a simple nitrogen plasma approach, resulting in efficient OER performance. The optimized N-MnO 2 v electrocatalyst exhibits outstanding OER activity in alkaline electrolyte, reducing the overpotential by nearly 160 mV compared to pure pristine MnO 2 (from 476 to 312 mV) at 10 mA cm -2 , and a small Tafel slope of 89 mV dec -1 . Moreover, it demonstrates excellent durability over a 122 h stability test. The introduction of O vacancies and incorporation of N not only fine-tune the electronic structure of MnO 2 , increasing the Mn 3+ content to enhance overall activity, but also play a crucial role in stabilizing Mn 3+ achieved through the two engineering methods, effectively lowering the intermediate adsorption free energy barrier. Our synergistic approach, utilizing nitrogen plasma treatment, opens a pathway to concurrently enhance the activity and stability of OER electrocatalysts, applicable not only to Mn-based but also to other transition metal oxides.2 achieved through the two engineering methods, effectively lowering the intermediate adsorption free energy barrier. Our synergistic approach, utilizing nitrogen plasma treatment, opens a pathway to concurrently enhance the activity and stability of OER electrocatalysts, applicable not only to Mn-based but also to other transition metal oxides.

This paper presents the one-dimensional simulation of the dielectric barrier discharge (DBD) in pure nitrogen at atmospheric pressure using a sinusoidal supply, within a reactor which consists of two parallel plates. For this purpose, significant reactions among the reactive species in the discharge are taken into account in this work by considering more than 70 reactions for 13 species. The model used in this study to describe the kinetics of the plasma species is the second order fluid model which consists in replacing the Boltzmann equation by these first three moments by using the drift-diffusion approximation for flux. In order to validate the model developed in this research, a comparison of the simulated discharge currents obtained with available experimental data is carried out, before presenting the evolution of the properties of the plasma species. After that, a parametric study is performed showing the effect of some parameters like applied voltage, frequency and nature of the coating dielectric material on the characteristics of DBD in nitrogen. Simulation results for a double dielectric DBD reactor are also presented at the end of this paper. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the effect of nitrogen plasma treatment on the shear bonding strength (SBS) of polyetheretherketone (PEEK) to resin cements. A total of 240 PEEK specimens were subjected to different duration of nitrogen plasma treatment for 0 min, 15 min, 25 min, 35 min respectively. The surface topography was observed by a scanning electron microscope (SEM). In addition, X-ray photoelectron spectroscopy (XPS) was applied to study the surface element content changes before and after treatment. The adhesive specimens were bonded with Variolink in all groups. Afterwards, each group was divided into three subgroups (n = 20/group), (a) water storage for 56 h at 37 °C, (b) thermal cycling for 5000 times, (c) thermal cycling for 10000 times. Following storage shear bond strength (SBS) was tested in a universal testing machine and the failure modes were observed by stereoscopic microscope. After plasma treatment, the bonding strength between PEEK and Variolink was significantly increased. Among them, the 25 min group achieved the highest bonding strength. After thermal cycling, the SBS values were significantly decreased, compared with the group in water storage. Nitrogen low temperature plasma treatment improves SBS between PEEK and resin, and a duration of 25 min treatment group seems to be the best. [ABSTRACT FROM AUTHOR]

Using a microwave‐excited plasma source based on a microstrip line, we have generated a nitrogen plasma jet at a moderate pressure in the range from 1 to 10 kPa. The densities of nitrogen (N) atoms produced by the plasma jet were measured with a vacuum ultraviolet absorption spectroscopy. The results show that the plasma jet is able to provide a high density of N atoms at least 4.5 × 1014 cm−3 at 1.5 kPa. The N atom densities vary widely with the change in gas flow rate and substrate placement. We expect that this plasma source will provide a high performance as an advanced N radical source in various applications. © 2020 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The ionization source is the central system of analytical devices such as mass spectrometers or ion mobility spectrometers. In this study, a recently developed flexible microtube plasma (FμTP) is applied as an ionization source for a custom-made drift tube ion mobility spectrometer (IMS) for the first time. The FµTP is based on a highly miniaturized, robust and a small-footprint dielectric barrier discharge design with an outstanding ionization efficiency. In this study, the experimental setup of the FµTP was further improved upon to achieve optimal coupling conditions in terms of the ion mobility spectrometry sensitivity and the plasma gas consumption. One major focus of this study was the adjustment of the electrical operation parameters, in particular, the high voltage amplitude, frequency and duty cycle, in order to minimize the electric field disturbances and yield higher signals. Additionally, the consumption of helium plasma gas was reduced by refining the FµTP. It was found that the ionization efficiency could be significantly enhanced by increasing the plasma high voltage and through application of a duty cycle up to 90:10. Plasma gas flows could be reduced down to 3 mL min-1 by increasing the plasma high voltage amplitude. Furthermore, a smaller wire electrode design enables the operation of the FµTP with nitrogen and clean air. Moreover, detection limits of a homologous series of ketones in the range of 330 ppt v (N 2 -FµTP, 2-decanone) down to 20 ppt v (He-FµTP, 2-octanone) could be reached in the optimized setup. To sum up, this feasibility study demonstrates the potential of the optimized FµTP as a powerful ionization source for ion mobility spectrometry especially with regard to ionization efficiency. Image 1 • Introducing the flexible microtube plasma as ionization source for a custom-built drift tube ion mobility spectrometer. • Stepwise optimization process of electrical operation parameters for maximum sensitivity thus reducing gas consumption. • Plasma gas (helium, nitrogen, clean air) with flow rates down to 3 mL min−1 were successfully ignited. • LODs of 330 ppt v (FµTP-gas: nitrogen) down to 20 ppt v (helium) for a homologous series of ketones were reached. • Enormous potential of this innovative ion source and the key role of individual adaptation to IMS geometry was proven. [ABSTRACT FROM AUTHOR]

The present study reports a novel and fast nitrogen plasma treatment approach to boost hydrogen evolution on antimony(III) sulphide (Sb2S3) thin films via light‐driven water splitting. The Sb2S3 films were synthesised by electrodepositing antimony followed by sulphurisation, and then using different treatment times under nitrogen plasma. The plasma treatment time did not result in significant changes in the microstructural and optical properties, compared to the non‐plasma films. However, the wettability drastically changed from superhydrophobic for the non‐plasma film to hydrophilic once treated. Photoelectrochemical analysis showed a substantial photocurrent density increase (24‐fold) for the film treated for 10 s in comparison with the non‐plasma film. Further characterisation by X‐ray photoelectron spectroscopy and scanning electron microscopy revealed chemical and morphological modifications for the films treated, which explain the enhancement of photoelectroactivity and wettability. [ABSTRACT FROM AUTHOR]

[Display omitted] • N-doped 1T-2H MoSe 2 /N doped carbon paper was fabricated by a low-temperature nitrogen plasma strategy. • N doping along with 1T phase into the 2H-MoSe 2 can expose more active edge sites and improve electrical conductivity. • N-MoSe 2 /NCP-30 only needs an overpotential of 274 mV to reach −200 mA cm−2 with Tafel slope of 54.7 mV dec-1. Molybdenum selenide (MoSe 2) is considered to be a promising catalyst for seawater hydrogen evolution, but its catalytic activity falls far short of requirements due to its inert surface. Here, self-supported N-doped 1T@2H-MoSe 2 /N doped carbon paper (N-MoSe 2 /NCP) was fabricated by a novel low-temperature nitrogen plasma strategy. In alkaline simulated seawater, the optimized N-MoSe 2 /NCP-30 only requires an overpotential of 274 mV to reach −200 mA cm−2 with Tafel slope of 54.7 mV dec-1, and exhibits stability over 24 h. This work proposes that the introduction of 1 T phase and N dopant into 2H-MoSe 2 using low-temperature plasma strategy can significantly facilitate the exposure of abundant active edge sites and boost the conductivity of MoSe 2. [ABSTRACT FROM AUTHOR]

Graphene was reported as the first-discovered two-dimensional material, and the thermal decomposition of SiC is a feasible route to prepare graphene films. However, it is difficult to obtain a uniform single-layer graphene avoiding the coexistence of multilayer graphene islands or bare substrate holes, which give rise to the degradation of device performance and becomes an obstacle for the further applications. Here, with the assistance of nitrogen plasma, we successfully obtained high-quality single-layer and bilayer graphene with large-scale and uniform surface via annealing 4H-SiC(0001) wafers. The highly flat surface and ordered terraces of the samples were characterized using in situ scanning tunneling microscopy. The Dirac bands in single-layer and bilayer graphene were measured using angle-resolved photoemission spectroscopy. X-ray photoelectron spectroscopy combined with Raman spectroscopy were used to determine the composition of the samples and to ensure no intercalation or chemical reaction of nitrogen with graphene. Our work has provided an efficient way to obtain the uniform single-layer and bilayer graphene films grown on a semiconductive substrate, which would be an ideal platform for fabricating two-dimensional devices based on graphene.

The smelting behavior of waste chromite ore fines containing Cr and Ni to produce crude Fe–Cr–Ni–N alloy was investigated in this study. In the experiments, for each heat, liquid steel melt (metal pool 1 kg) was prepared in a 3--capacity laboratory-scale electric arc furnace for the absorption of reduced metals like chromium, nickel, etc., under hydrogen and nitrogen plasma atmosphere at ~ 1600 °C temperature. The result shows the formation of crude alloy containing ~ 13% Cr, ~ 3% Ni along with ~ 500 ppm nitrogen. The highest recovery level of chromium was achieved ~ 63% in 20-min nitrogen plasma exposure. A negligible amount of chromium recovery (14.73%) in case of only hydrogen plasma and improved recovery (60%) for a combination of carbon and hydrogen plasma was observed. Suitable nitrogen level in the Fe–Cr melt can replace the required nickel content for making austenitic stainless steel. Hence, smelting reduction of chromite ore fines in the plasma arc furnace could be feasible to produce crude Fe–Cr–Ni–N alloy. This alloy could be used for making austenitic stainless steel after adopting suitable decarburization techniques. [ABSTRACT FROM AUTHOR]