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[Display omitted] • A high barrier RC film was prepared by coagulation bath coupled with PECVD. • The oxygen transmission rate of the composite film was 31.21 cm3/(m2·d). • The water contact angle of the composite film was 116.7°. • The composite film was completely degraded in soil within 35 days. Regenerated cellulose (RC) films are considered a sustainable packaging material that can replace non-degradable petroleum-based plastics. However, their susceptibility to water vapor and oxygen can limit their effectiveness in protecting products. This study introduces a novel approach for enhancing RC films to create durable, flexible, hydrophobic, high-barrier, and biodegradable packaging materials. By exploring the impact of ascorbic acid coagulation bath treatment and plasma-enhanced chemical vapor deposition (PECVD) on the properties of RC films, we found that the coagulation bath treatment facilitated the organized reconfiguration of cellulose chains, while PECVD applied a dense SiO x coating on the film surface. The results demonstrated a significant enhancement in water vapor and oxygen barrier properties of the composite film, almost reaching the level of commercial barrier films. Moreover, the composite film displayed exceptional biodegradability, fully degrading in soil within 35 days. Additionally, it showcased impressive mechanical strength, hydrophobic characteristics, and freshness preservation, positioning it as a valuable option for bio-based high-barrier packaging applications. [ABSTRACT FROM AUTHOR]

Semiconductor industry is experiencing a rising demand for environmentally friendly processes with the emphasis on green policies and worldwide environmental sustainability. Nitrogen trifluoride (NF3), the most common plasma chamber cleaning agent gas, poses a significant concern as a potent greenhouse gas since it has global warming potential (GWP), 740 times and 6 times higher than that CO2 and N2O. This study investigated the exhaust gas using quadrupole mass spectroscopy (QMS) and analyzed the change in cleaning speed and the type of exhaust gas through plasma monitoring using optical mass spectroscopy (OES). The objective is to lower the use of the amount of NF3 gas in chamber cleaning process to partially contribute the environmental sustainability in the point of semiconductor manufacturing. When a small amount of N2 was added to NF3 whose ratio of 7:23, the cleaning efficiency reached to 90% compared to NF3 gas alone. Addition of N2 positively affected electron density and temperature to increase the F-radical in remote plasma system. In conclusion, 18% of NF3 usage amount was reduced during the Sio2 deposition chamber cleaning process. [ABSTRACT FROM AUTHOR]

The study of BP layers and BP/n-Si heterojunctions formed by plasma enhanced chemical deposition on n-Si substrates has been carried out at a temperature of 350 °C using diborane and phosphine. The additional enhancement of hydrogen plasma power was established to make it possible to avoid pinning of the Fermi level at the BP/n-Si interface. Moreover, additional dilution with a hydrogen flow led to an increase in the BP layer conductivity, and the behavior of the current-voltage characteristic of the Au/BP/n-Si structure (golden electrode) became rectifying. Surface states of electrons at the BP/n-Si heterojunctions in all the samples and deep electronic levels with energy 0.58–0.65 eV in BP layers grown without the additional hydrogen flow were detected by admittance spectroscopy.

The drilling of printed circuit board (PCB) using micro-drills is an important processing method in modern industry. A protective film with good lubricating and anti-wear properties is generally applied to improve the processing problems of micro-drills during operation. In this study, the effects of C2H2 flow rate on the microstructure, mechanical, and tribological properties of a-C:H films deposited by plasma enhanced chemical vapor deposition (PECVD) technique were investigated. The results showed that when the C2H2 flow rate was low, varying the flow rate had little effect on the microstructure of the prepared a-C:H films. However, when the C2H2 flow rate was greater than 210 sccm, the increase in flow rate caused large particles of carbon clusters to aggregate on the surface of a-C:H films, which resulting in an increase Ra value. Not only did it reduce the adhesion between the film and the substrate, but it also deteriorated the mechanical and tribological properties of the a-C:H film produced. In addition, a-C:H films were also deposited on the micro-drill, and were used for drilling tests on the PCBs to evaluate its servce capability. The optimal parameters of a-C:H film deposited on the micro-drill surface were obtained by observing the morphology of the micro-drill surface after drilling and the hole accuracy statistics. The results showed that a-C:H film deposited on the surface of the micro-drill showed the best machining performance when the C2H2 flow rate was 180 sccm. The surface wear of micro-drill was minimal, the entanglement of tangled chips was minimal. The value of the process capability index (CPK) after 500, 1000, and 2000 drilling of PCB boards was 5.95, 4.33, and 3.15 respectively, which showed the highest drilling accuracy. This is mainly attributed to the better overall properties of the a-C:H films prepared at C2H2 flow rate of 180 sccm, such as lower surface roughness, lowest residual stress, higher hardness, better adhesion, and lower friction coefficient.

Practical and efficient integrations of graphene into real applications are identically important as their various superior properties. Among various graphene-related materials, vertical graphene stripes (VGSs, in nanoscale) are one kind of interconnected graphene sheet oriented perpendicularly to the growth substrate with 3-dimensional porous structures. Due to the high surface-to-volume ratio, VGSs could be an even better candidate than pure graphene when considering the physical mixing of graphene-related materials with other substances. In this study, we demonstrate an organic-catalysis-free and low-temperature approach (

In this work, we study the influence of the different surface terminations of c-plane sapphire substrates on the synthesis of graphene via plasma-enhanced chemical vapor deposition. The different terminations of the sapphire surface are controlled by a plasma process. A design of experiments procedure was carried out to evaluate the major effects governing the plasma process of four different parameters: i.e., discharge power, time, pressure and gas employed. In the characterization of the substrate, two sapphire surface terminations were identified and characterized by means of contact angle measurements, being a hydrophilic (hydrophobic) surface and the fingerprint of an Al- (OH-) terminated surface, respectively. The defects within the synthesized graphene were analyzed by Raman spectroscopy. Notably, we found that the ID/IG ratio decreases for graphene grown on OH-terminated surfaces. Furthermore, two different regimes related to the nature of graphene defects were identified and, depending on the sapphire terminated surface, are bound either to vacancy or boundary-like defects. Finally, studying the density of defects and the crystallite area, as well as their relationship with the sapphire surface termination, paves the way for increasing the crystallinity of the synthesized graphene. [ABSTRACT FROM AUTHOR]

Since decades, the PECVD ('plasma enhanced chemical vapor deposition') processes have emerged as one of the most convenient and versatile approaches to synthesize either organic or inorganic thin films on many types of substrates, including complex shapes. As a consequence, PECVD is today utilized in many fields of application ranging from microelectronic circuit fabrication to optics/photonics, biotechnology, energy, smart textiles, and many others. Nevertheless, owing to the complexity of the process including numerous gas phase and surface reactions, the fabrication of tailor-made materials for a given application is still a major challenge in the field making it obvious that mastery of the technique can only be achieved through the fundamental understanding of the chemical and physical phenomena involved in the film formation. In this context, the aim of this foundation paper is to share with the readers our perception and understanding of the basic principles behind the formation of PECVD layers considering the co-existence of different reaction pathways that can be tailored by controlling the energy dissipated in the gas phase and/or at the growing surface. We demonstrate that the key parameters controlling the functional properties of the PECVD films are similar whether they are inorganic- or organic-like (plasma polymers) in nature, thus supporting a unified description of the PECVD process. Several concrete examples of the gas phase processes and the film behavior illustrate our vision. To complete the document, we also discuss the present and future trends in the development of the PECVD processes and provide examples of important industrial applications using this powerful and versatile technology. [ABSTRACT FROM AUTHOR]

This work presents experimental results on the synthesis of сarbon nanowalls (CNWs) with predefined morphology on the surface of the nanoporous alumina membrane using two different methods, namely radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) and radical-injection (RI)-PECVD. Obtained samples were characterized by the methods of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. From the microstructure analyses of CNWs, it has been observed that there is a time dependence on the reproducibility of membrane morphology by CNWs. At the early stage of nanowalls growth, nanowalls prefer to grow around the edges of nanopores and continue to grow vertically with time. In RF-PECVD, the nanopores' size begins to shrink drastically and pores are completely covered by secondary flake-like nanowalls after 25 minutes of growth. In the case of CNWs grown using RI-PECVD, nanowalls are more vertical and self-supported. This is because of the rapid and sustained production of hydrogen radicals that prevent the secondary growth of carbon nanowalls. In addition, the influence of pores diameter and membrane thickness on the growth of RI-PECVD CNWs was revealed. [ABSTRACT FROM AUTHOR]

• The mechanism of microwave plasma enhanced chemical vapor deposition of vertical carbon nanoflakes (CNFs) on Ti substrate was proposed as function of temperature in plasma chamber. • The resultant CNFs can be applied to assemble supercapacitors with no requirement of post treatment. • Symmetric supercapacitor with GNFs electrodes showed Coulombic efficiency of 99 % for 10,000 life cycles. As energy storage materials are in an urgent demand and carbon-based nanomaterials provided great potential for battery and supercapacitor. This study applied microwave plasma enhanced chemical vapor deposition (MPE-CVD) to deposit 3-dimensional carbon nanoflakes (CNFs) with distinguished surface area to prepare the electrodes for electric double layer capacitors (EDLCs). The vertical growth of CNFs is driven by MPE-CVD using CH 4 as precursor gas. The as-prepared CNFs on titanium plate (CNFs _700 /Ti) was optimized by thickness and mass loading as function of the applied power. Raman spectroscopy and field emission scanning electron microscopy analyzed the properties and surface morphology of carbon. The electrochemical properties of the CNFs _700 /Ti assembled as Swagelok or pouch cell were evaluated by cyclic voltammetry and galvanostatic charge/discharge for potential developments in supercapacitor. An unprecedented rapid growth rate of CNFs, 180 μm/h, was dramatically accelerated due to MPE-CVD procedure, and could be applied as electrode for EDLCs. The mechanism of CNFs growth was elucidated based on the temperature measurements in reactor which relates closely to the CNFs growth rate, proved by thickness and mass loading of CNFs. The clarification of CNFs growth mechanism assists future developments of carbon-based materials in energy storage materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Heteroepitaxial growth of Ge films on Si is necessary for the progress of integrated Si photonics technology. In this work, an in-house assembled plasma enhanced chemical vapor deposition reactor was used to grow high quality epitaxial Ge films on Si (100) substrates. Low economic and thermal budget were accomplished by the avoidance of ultra-high vacuum conditions or high temperature substrate pre-deposition bake for the process. Films were deposited with and without plasma assistance using germane (GeH4) precursor in a single step at process temperatures of 350–385 °C and chamber pressures of 1–10 Torr at various precursor flow rates. Film growth was realized at high ambient chamber pressures (>10−6 Torr) by utilizing a rigorous ex situ substrate cleaning process, closely controlling substrate loading times, chamber pumping and the dead-time prior to the initiation of film growth. Plasma allowed for higher film deposition rates at lower processing temperatures. An epitaxial growth was confirmed by X-Ray diffraction studies, while crystalline quality of the films was verified by X-ray rocking curve, Raman spectroscopy, transmission electron microscopy and infra-red spectroscopy.

Plasma- polymerized coatings were successfully applied on aluminum alloy, AA2024, surface for corrosion protection. The plasma polymerization process was carried out by low pressure microwave plasma at room temperature. The effect of microwave plasma power on the corrosion resistance of polymer coatings was investigated using the potentiodynamic polarization technique. As the microwave plasma power increased, the relative protective efficiency increased. Polymer coatings on alloy surfaces suppressed both anodic and cathodic reactions. The increment in protective efficiency was due to a higher degree of cross-linking in the coating. These findings suggest that the toluene polymer coatings provide a considerable protection barrier for aluminum alloys.

In this work, we study the influence of the different surface terminations of c-plane sapphire substrates on the synthesis of graphene via plasma-enhanced chemical vapor deposition. The different terminations of the sapphire surface are controlled by a plasma process. A design of experiments procedure was carried out to evaluate the major effects governing the plasma process of four different parameters: i.e., discharge power, time, pressure and gas employed. In the characterization of the substrate, two sapphire surface terminations were identified and characterized by means of contact angle measurements, being a hydrophilic (hydrophobic) surface and the fingerprint of an Al- (OH-) terminated surface, respectively. The defects within the synthesized graphene were analyzed by Raman spectroscopy. Notably, we found that the ID/IG ratio decreases for graphene grown on OH-terminated surfaces. Furthermore, two different regimes related to the nature of graphene defects were identified and, depending on the sapphire terminated surface, are bound either to vacancy or boundary-like defects. Finally, studying the density of defects and the crystallite area, as well as their relationship with the sapphire surface termination, paves the way for increasing the crystallinity of the synthesized graphene.

In this paper the opto‐electrical nature of hydrogenated group IV alloys with optical bandgap energies ranging from 1.0 eV up to 2.3 eV are studied. The fundamental physical principles that determine the relation between the bandgap and the structural characteristics such as material density, elemental composition, void fraction and crystalline phase fraction are revealed. Next, the fundamental physical principles that determine the relation between the bandgap and electrical properties such as the dark conductivity, activation energy, and photoresponse are discussed. The unique wide range of IV valence alloys helps to understand the nature of amorphous (a‐) and nanocrystalline (nc‐) hydrogenated (:H) germanium films with respect to the intrinsicity, chemical stability, and photoresponse. These insights resulted in the discovery of i) a processing window that results in chemically stable Ge:H films with the lowest reported dark conductivity values down to 4.6·10‐4 (Ω ·cm)‐1 for chemical vapor deposited Ge:H films, and ii) O, C and Sn alloying approaches to improve the photoresponse and chemical stability of the a/nc‐Ge:H alloys. [ABSTRACT FROM AUTHOR]

Direct manufacturing of two-dimensional material-based double barrier (DB) tunnel junctions, based on a lithography-free approach was developed. Graphene/h-BN/Graphene/h-BN/Graphene devices were deposited on Si/SiO2 substrates by employing a plasma enhanced chemical vapor deposition technique in a sequential manner. DB tunneling junctions with varying barrier widths (by varying the thickness of the second graphene layer) were studied. Samples were characterized using Raman, Atomic Force Microscopy and X-ray photoemission spectroscopy. The I–V characteristics of tunneling current showed resonant tunneling behavior at room temperature with a negative differential conductance. The behavior could be explained with quantum mechanical double barrier tunneling model in which analytic solutions to Schrödinger's equation were obtained in each region of the system. Resonances in transmission probability coefficient for varying barrier widths were evaluated and compared with the experimental results. [ABSTRACT FROM AUTHOR]

In this work, we emphasis on the Bismuth induced crystallization of hydrogenated amorphous silicon (a-Si) thin films. 50 nm of bismuth thin films are deposited by vapor deposition on Silicon substrates. Then, bismuth covered Si substrates are coated with 100 nm thin film of a-Si: H elaborated at fixed growth conditions by plasma enhanced chemical vapor deposition. Annealing experiments were performed by IR thermal processing under N2 atmosphere at temperature ranging from 300 to 500 °C. The effect of annealing temperature on Bismuth induced crystallization of amorphous silicon has been evaluated in terms of crystalline modes and fractions, preferential orientations, average surface roughness and atom distributions. Using X-ray diffraction, atomic force and scanning electron microcopies as well as Raman spectroscopy, the correlation between crystalline fraction and the electrical conductivity as well as X-ray photoelectron spectrometry has been made. [ABSTRACT FROM AUTHOR]

Abstract In this paper the opto‐electrical nature of hydrogenated group IV alloys with optical bandgap energies ranging from 1.0 eV up to 2.3 eV are studied. The fundamental physical principles that determine the relation between the bandgap and the structural characteristics such as material density, elemental composition, void fraction and crystalline phase fraction are revealed. Next, the fundamental physical principles that determine the relation between the bandgap and electrical properties such as the dark conductivity, activation energy, and photoresponse are discussed. The unique wide range of IV valence alloys helps to understand the nature of amorphous (a‐) and nanocrystalline (nc‐) hydrogenated (:H) germanium films with respect to the intrinsicity, chemical stability, and photoresponse. These insights resulted in the discovery of i) a processing window that results in chemically stable Ge:H films with the lowest reported dark conductivity values down to 4.6·10‐4 (Ω ·cm)‐1 for chemical vapor deposited Ge:H films, and ii) O, C and Sn alloying approaches to improve the photoresponse and chemical stability of the a/nc‐Ge:H alloys.

Based on the basic principle and algorithm of multi-layer optical thin films, SiO2/Si3N4 double-layer antireflection films for three-junction reverse GaAs solar cells were prepared on GaAs substrate by plasma enhanced chemical vapor deposition (PECVD). The relationships between post-annealing and the morphology, structure and optical properties of the multilayer films were characterized by atomic force microscope (AFM), Fourier transform infrared spectrometer (FT-IR), elliptical polarizer, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis spectrophotometer. The results indicate that the films are crystalline state both before and after annealing. With the increase of annealing temperature, the roughness and average reflectance gradually decrease. SiO2/Si3N4 films annealed at 700 ℃ have the best performance with the lowest average reflectance of 12.65% and roughness of 1.64 nm. The spectral curve of the films move towards to short-wave direction about 30 nm, showing a typical "blue-shift" phenomenon, which indicates that the optical thickness of the films demonstrates a declining trend with the rising of annealing temperature.

Abstract Thin a-C:H:Si:O:N films were deposited from plasmas fed hexamethyldisiloxane, oxygen and nitrogen, and characterized as a function of the partial pressure of oxygen in the feed, Rox. Deposition rates varied from 10 to 27 nm min-1. Surface roughness was independent of Rox, being around 10 nm. The films contain C=C and C=O, and also Si-C and Si-O-Si groups. Lower [C] and [N] but greater [O] and [Si] were measured in the films as Rox was increased. Refractive indices of ~ 1.5 and optical energy gaps which fell from ~ 3.3 to ~2.3 eV were observed with increasing Rox. The Urbach energy fell with increasing optical gap, which is characteristic of amorphous materials. Such materials have potential as transparent barrier coatings.

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Increasingly more young patients have been submitted to reconstruction of the Temporomandibular Joint (TMJ), so, the prostheses must to present more functional longevity. Objective: To evaluate the effect of diamond-like carbon film (DLC) over titanium alloy (Ti6Al4V) and polyethylene (UHWPE) samples, their mechanical and chemical properties and cellular cytotoxicity. Methods: Titanium and UHWPE specimens, with 2.5 cm in diameter and 2 mm thickness were coated through plasma enhanced chemical vapor deposition (PECVD) with DLC or DLC doped with silver (DLC-Ag). Scanning electron microscopy (SEM) morphological analysis, Energy-dispersive spectroscopy (EDS) chemical analysis, scratching test, mechanical fatigue test, surface roughness analysis, and cellular cytotoxicity were performed. Data were statistically analyzed using one-way ANOVA (p

Copyright of Journal of Materials Science & Engineering (1673-2812) is the property of Journal of Materials Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Effects of different pulse widths on morphologies and corrosion resistance of diamond-like carbon (DLC) coatings prepared on the surface of high nitrogen nickel-free stainless steel (HNSS) were investigated. It was found that different pulse widths of 10, 15 and 20 μ s mainly affect the porosity and internal stress within the coatings. The energies of the implantation ions were decreased as the pulse width increase. The growth mechanism of the coating with the pulse width of 20 μ s was mainly surface diffusion, in which the coating was porous and prone to corrosion. With the decrease of pulse width, the growth mechanism was mainly sub-plantation. The DLC coating became dense and the corrosion resistance was improved significantly. However, with further decrease of pulse width, internal stress within the coating was also increased. The effect of stress corrosion cracking may decrease the corrosion resistance of the DLC coating with the pulse width of 10 μ s. The influencing mechanisms of the pulse width on corrosion resistance and growth mechanism of DLC coating on the surface of HNSS are also discussed. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The composition of hydrogen and hydrogen-methane plasmas containing ~ 10% of BX3, SiX4, GeX4 (X = F, Cl), SF6, MoF6 and WF6 is calculated for the temperature range ~ 300–4000 K using the equilibrium chemical model. The calculations provide valuable information about thermodynamic parameters (pressure, temperature) needed for condensation of pure elements (in H2 plasma) and their carbides (in H2 + CH4 plasma) and about intermediate reaction products. Using volatile fluorides for plasma chemical deposition alleviates obtaining monoisotopic elements and their isotopic compounds because fluorine is monoisotopic. PECVD is promising method for one-step conversion of fluorides to elemental isotopes and their carbides. For fluorides, further insight is needed into properties of plasmas supported by different types of discharges. [ABSTRACT FROM AUTHOR]

Physical vapor deposition - plasma enhanced chemical vapor deposition (PVD-PECVD) system has been used exclusively for deposition and doping of carbonaceous films [silver nanoparticles (Ag-NPs)] on cotton fabrics and the findings are compared, in terms of technical efficiency and microbial inhibition, with those of the magnetron sputtering (MS) technique. It is found that the proposed technique presents promising characteristics for the deposition of silver nanoparticles (Ag-NPs) on textiles, which meet the industrial demand. [ABSTRACT FROM AUTHOR]

In this study, we propose a mass production-able and low-cost method to fabricate the anodes of Li-ion battery. Carbonaceous anodes, integrated with thin amorphous silicon layers by plasma enhanced chemical vapor deposition, can improve the performance of specific capacity and coulombic efficiency for Li-ion battery. Three different thicknesses of a-Si layers (320, 640, and 960 nm), less than 0.1 wt% of anode electrode, were deposited on carbonaceous electrodes at low temperature 200◦C. Around 30 mg of a-Si by plasma enhanced chemical vapor deposition (PECVD) can improve the specific capacity ~42%, and keep coulombic efficiency of the half Li-ion cells higher than 85% after first cycle charge-discharge test. For the thirty cyclic performance and rate capability, capacitance retention can maintain above 96%. The thicker a-Si layers on carbon anodes, the better electrochemical performance of anodes with silicon-carbon composites we get. The traditional carbonaceous electrodes can be deposited a-Si layers easily by plasma enhanced chemical vapor deposition, which is a method with high potential for industrialization. [ABSTRACT FROM AUTHOR]

Radio frequency plasma enhanced chemical vapor deposition (rf-PECVD) is an efficient technique for preparing hydrogenated amorphous silicon (a-Si:H) layers used in thin film silicon solar cells. The most important parameters in a PECVD system are the chamber pressure, substrate temperature, partial gas flow, plasma power, electrode spacing, and deposition time, by which the physical and electrical parameters of the deposited layers, such as phase, quality, thickness, doping concentration, energy gap, defect density, and mobility can be controlled. Moreover, some of the film parameters are indirectly related to the others. As a result, it is always difficult to describe the relations between the deposition parameters and the specifications of the deposited layer in closed-form equations, therefore, prediction of the properties of the deposited films remains an issue. In addition, the helpful facilities for in-situ monitoring of the film under deposition are very limited. In this research, based on a broad experimental data reported in the literature, it has been found that in many cases the performance of a PECVD system can be described in equation or graph forms, and effective estimations may be established for prediction of its performance. A flowchart is also presented to explain the steps required for adjusting the input parameters of the system for the fabrication of a desired layer, which can reduce the complexity of interrelations among the variables, leading to a more accurate and flexible process design. [ABSTRACT FROM AUTHOR]

A multilayer plasma polymer coating was deposited on small glass discs and afterwards treated with ultra violet radiation through a patterned mask to generate a micro-structured substrate with an alternating hydrophilic/hydrophobic surface. The substrate was then immersed in a mother liqueur of the porous, functional material Metal-Organic Framework Ulm-4 (MFU-4) to preferentially grow crystals on the hydrophilic areas of the film. X-ray diffraction and electron microscope analysis showed the formation of MFU-4 single crystals. • Chemically robust micro-structured, multilayer plasma polymer coating • Hydrophobic polytetrafluoroethylene-like coating deposited from trifluoromethane • Spatially directed crystal growth of a porous functional material [ABSTRACT FROM AUTHOR]

Increasingly more young patients have been submitted to reconstruction of the Temporomandibular Joint (TMJ), so, the prostheses must to present more functional longevity. To evaluate the effect of diamond-like carbon film (DLC) over titanium alloy (Ti6Al4V) and polyethylene (UHWPE) samples, their mechanical and chemical properties and cellular cytotoxicity. Titanium and UHWPE specimens, with 2.5 cm in diameter and 2 mm thickness were coated through plasma enhanced chemical vapor deposition (PECVD) with DLC or DLC doped with silver (DLC-Ag). Scanning electron microscopy (SEM) morphological analysis, Energy-dispersive spectroscopy (EDS) chemical analysis, scratching test, mechanical fatigue test, surface roughness analysis, and cellular cytotoxicity were performed. Data were statistically analyzed using one-way ANOVA (p < 0.05) or two-way ANOVA and multiple comparison Tukey test. In the SEM analysis, morphological differences were observed on substrates after DLC deposition. The film chemically modified the substrate surfaces, according to the EDS analysis. The initial critical load failure occurred at 6.1 N for DLC and 9.7 N for the DLC-Ag film. The DLC film deposition over the polyethylene promoted a decrease in the polymer's damaged area after mechanical fatigue cycling. The cytotoxicity analysis demonstrated less biocompatibility in experimental groups, when compared to control, however, increased biocompatibility was observed, at 10 days, in all groups. The diamond-like carbon coating enhanced the chemical and mechanical properties from substrates, however modified biological interaction course of the titanium alloy (Ti6Al4V) and polyethylene (UHWPE) samples. Parameters for film deposition remain to be improved in order to obtain best biocompatibility. [ABSTRACT FROM AUTHOR]

The approach, which was developed earlier for modeling chemical reactions in laser induced plasmas, is applied to radio-frequency discharge plasmas. The model is based on the assumption that all ionization processes and chemical reactions are at local thermodynamic equilibrium. A chemical composition of an argon-hydrogen plasma with an addition of boron trichloride is studied as a function of plasma temperature and mole ratio H 2 / BCl 3 . It is established that more than twenty simple and composite molecules and ions can be formed in the course of chemical reactions. The results are compared with those obtained earlier by means of another equilibrium model that uses ab-initio quantum chemical computations of thermochemical and kinetic data and a 0D thermochemical equilibrium solver. [ABSTRACT FROM AUTHOR]

Abstract Long service life of implants is of high importance to patients. This study deposited amorphous carbon (a-C) coatings on biomedical grade Ti6Al4V substrate using plasma-enhanced chemical vapor deposition (PECVD). The effect of substrate bias power on microstructure and corrosion of the coatings is investigated and compared with the bare Ti6Al4V substrate. The experimental results show that the substrate bias power of 30 W leads to amorphous carbon in microstructure. With increased bias nanocrystalline graphite appears. All coated samples have significant improvements in corrosion resistivity as compared to Ti6Al4V alone. The sample deposited at bias power of 30 W with a thickness of 150 nm demonstrated the lowest corrosion current of 6.47 nA/cm2 and the lowest corrosion rate of 8.05 nm/year, which can postpone the corrosion of the Ti6Al4V substrate for at least 18 years. From the in-vitro cell culture studies, the best sample also registered the higher cell viability and biocompatibility as compared to bare Ti6Al4V, thus could be helpful in promoting healing. Highlights • Different substrate bias power leads to varying microstructures of a-C. • Best a-C coating has corrosion rate of 8 nm/year, 47 times less than bare Ti6Al4V. • a-C coatings are nontoxic, and have higher biocompatibility than bare Ti6Al4V. [ABSTRACT FROM AUTHOR]

Antibacterial surfaces are crucial to hinder the spread of pathogens infections, especially when high-touch surfaces (HTS) are involved, as in the case of food packaging. Nature can be inspiring, offering plenty of nanotextured surfaces with high antibacterial activity. Herein, poly(butylene succinate) (PBS), one of the most reliable biodegradable plastic used in food packaging, was nanotextured by a low pressure plasma oxygen etching. Moreover, the deposition of SiO X coatings ≈15 nm thick by plasma enhanced chemical vapor deposition (PECVD) was carried out to improve gas barrier properties of the nanotextured polymers. Based on experimental findings, a hypothesis for the nanotexturing mechanism in our plasma experimental set-up has been figured out. The antibacterial properties were tested against E. coli and S. aureus , showing in both cases a strong inhibitory effect by a factor of >4 log 10 CFU cm−2. Finally, the oxygen diffusion permeability coefficients (P O2) were also measured, and the oxygen transmission rates (OTR) were calculated as an indicator of the gas barrier performance of the samples. As expected, plasma etching impacted negatively on the oxygen permeability. However, by coating with SiO x , the treated PBS showed a 30 % decrease of the OTR compared even to the untreated PBS. [Display omitted] • Low pressure plasma oxygen etching was employed to nanotexture poly(butylene succinate) (PBS). • Surface nanotexturing is achieved without relying on the contamination by metallic impurities. • The PBS semicrystalline structure is the reason for the surface nanotexturing • Nanotextured PBS SiOx shows high antibacterial activity combined to a decreased OTR. [ABSTRACT FROM AUTHOR]

To develop a synthesis technique providing enhanced control of graphene film quality and uniformity, a systematic characterization and manipulation of hydrocarbon precursors generated during plasma enhanced chemical vapor deposition of graphene is presented. Remote ionization of acetylene is observed to generate a variety of neutral and ionized hydrocarbon precursors, while in situ manipulation of the size and reactivity of carbon species permitted to interact with the growth catalyst enables control of the resultant graphene morphology. Selective screening of high energy hydrocarbon ions coupled with a multistage bias growth regime results in the production of 90% few-to-monolayer graphene on 50 nm Ni/Cu alloy catalysts at 500 °C. Additionally, synthesis with low power secondary ionization processes is performed and reveals further control during the growth, enabling a 50% reduction in average defect densities throughout the film. Mass spectrometry and UV-Vis spectroscopy monitoring of the reaction environment in conjunction with Raman characterization of the synthesized graphene films facilitates correlation of the carbon species permitted to reach the catalyst surface to the ultimate quality, layer number, and uniformity of the graphene film. These findings reveal a robust technique to control graphene synthesis pathways during plasma enhanced chemical vapor deposition.

Vertically aligned multi-walled carbon nanotubes (VA-MWCNTs) with an average diameter below 80 nm and a thickness of the uniform VA-MWCNT layer of about 16 µm were grown in microwave plasma torch and tested for selected functional properties. IR absorption important for a construction of bolometers was studied by Fourier transform infrared spectroscopy. Basic electrochemical characterization was performed by cyclic voltammetry. Comparing the obtained results with the standard or MWCNT‑modified screen-printed electrodes, the prepared VA-MWCNT electrodes indicated their high potential for the construction of electrochemical sensors. Resistive CNT gas sensor revealed a good sensitivity to ammonia taking into account room temperature operation. Field emission detected from CNTs was suitable for the pressure sensing application based on the measurement of emission current in the diode structure with bending diaphragm. The advantages of microwave plasma torch growth of CNTs, i.e., fast processing and versatility of the process, can be therefore fully exploited for the integration of surface-bound grown CNTs into various sensing structures.

A qualified support material for Pt must has numerous deposition sites for Pt nanoparticles and great electrical conductivity. Metal oxide materials are potential support materials for Pt nanoparticles. However, they have less deposition sites for Pt and worse electronic conductivity than carbon. Carbon over the surface of metal oxide materials can improve the above shortage. In this paper, antimony tin oxide (ATO) coated by carbon layer has been successfully prepared by plasma enhanced chemical vapor deposition method (PECVD). PECVD can provide a brief approach to enwrap metal oxide with carbon at low temperatures. Besides, it becomes easier to control the amount of carbon by the PECVD to create much more two‐phase interface for Pt deposition. The carbon layer promotes the electronic conductivity of ATO and provides more deposition sites for platinum nanoparticles, which directly influence the size of Pt nanoparticles as well as the electrochemical active surface areas. The as‐prepared catalyst exhibits excellent activity for methanol oxidation reaction (MOR), which is twice of that of the commercial Pt/C catalyst. Meanwhile, it has better stability than the commercial Pt/C. [ABSTRACT FROM AUTHOR]

Deposition of functional metal films onto mechanically-sensitive nanostructures has been challenging as conventional wet reduction process could easily lead to physical damages and structural inhomogeneity at nanometer length scale. As PECVD technique not only offers noninvasive approach to single layer metal coating, it also entails processes’ scalability and cost-effectiveness. In this study, we investigate the formation of metal nanolayers on visible-light active ZnWO 4 -TiO 2 nanofibrous membrane as a model substrate against pilot-scale PECVD reactor drum’s rotating speed as a key parameter at fixed internal pressure and power input. The characteristics of sputtered Ag particles are fully examined by XRD, TEM and XPS techniques. At low rotating speed (less than 0.1 m/min), thick layer of silver is observed with strong antibacterial function. At high speed (more than 18 m/min) silver thin film disappears as silver nanoislands emerge on surface of the metal oxide nanofibrous substrate suggesting nucleation stage of silver deposition. Interestingly, at 6 m/min, the obtained metal-metal oxide hybrid shows enhanced photocatalytic activity and excellent antibacterial property. [ABSTRACT FROM AUTHOR]

Polycrystalline (100) textured diamond films containing mixture of micrometer scale crystallites and surrounding them smaller size diamonds and disordered carbon were obtained by chemical vapor deposition from methane‑hydrogen gas mixture activated by a direct current discharge (DC CVD). The films were oxidized during exposure in air at temperature providing selective volatilization of the smallest fraction of diamond crystallites and disordered carbon material. Structural peculiarities of the material remaining after film oxidation were analyzed by electron microscopy and compared with results of computer simulations. The simulations were performed using two dimensional empirical model designed to describe formation of {111} and {100} facets of the diamond crystallites during CVD. The porous and disordered structures at {111} growing facets predicted by the simulation are in excellent agreement with the experimental observations. [ABSTRACT FROM AUTHOR]

The relationship between processing conditions and specific chemical reactions led to film growth in plasma is identified by optical emission spectroscopy to simplify the optimization process of film properties. SiH ⁎ transient behavior after plasma ignition in parallel plate silane/germane/hydrogen plasma is investigated with the variation of germane, hydrogen flow rate and power. The effect on interface property between p layer and intrinsic layer in amorphous silicon germanium solar cell is obtained. H α ⁎ , H β ⁎ , SiH ⁎ and GeH ⁎ emission intensity is recorded when germane and silane/germane flow rate changes. Ge content is analyzed by optical band gap and Raman spectra of amorphous silicon germanium films. The results are expected to serve as a guide for improving the performance of solar cells. [ABSTRACT FROM AUTHOR]

Nanoparticles are coated in-flight with a plasma-enhanced chemical vapor deposition (PECVD) process at ambient or elevated temperatures (up to 300 °C). Two silicon precursors, tetraethyl orthosilicate (TEOS) and hexamethyldisiloxane (HMDSO), are used to produce inorganic silica or silica-organic shells on Pt, Au and TiO2 particles. The morphology of the coated particles is examined with transmission electron microscopy (TEM) and the chemical composition is studied with Fourier-transform infrared spectroscopy (FTIR), Energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). It is found that both the precursor and certain core materials have an influence on the coating composition, while other parameters, such as the precursor concentration, aerosol residence time and temperature, influence the morphology, but hardly the chemical composition. The coated particles are used to demonstrate simple applications, such as the modification of the surface wettability of powders and the improvement or hampering of the photocatalytic activity of titania particles. [ABSTRACT FROM AUTHOR]

This work deals with the processing and surface treatment of thermoplastic composites carbon fibers/Polyphenylene sulfide (CF/PPS) for aerospace applications. After the production of the thermoplastic composites through hot compression molding, a silicon deposition was carried out on its surface using Plasma Enhanced Chemical Vapor Deposition (PECVD). Then, the Plasma Immersion Ion Implantation (PIII) process was executed on the silicon coated samples to create an amorphous silicon nitride layer. Subsequently, the coated and uncoated samples were characterized by means of the following techniques: optical microscopy, atomic force microscopy (AFM), X-ray diffraction (XRD) and X-ray excited photoelectron spectroscopy (XPS). By analyzing all the results obtained from the characterizations, it was concluded that a layer of amorphous silicon oxynitride was generated on the CF/PPS composite without damaging it. This result is an innovative step concerning the application of this material in a space environment (low earth orbit). [ABSTRACT FROM AUTHOR]

In situ deposition method is adopted for preparing boron-doped silicon oxide thin film containing silicon quantum dot at the relative low substrate temperature of 200 °C. Argon dilution is applied in the deposition process, and various characterizations have been carried out for systematically investigating the effect of Ar flow on the structural, electrical, and optical properties of the samples. It is found that there is a phase transition from amorphous phase to crystalline phase as the Ar flow increases to 100 sccm. XPS results reveal that the O/Si atomic ratio declines with the increasing Ar flow whereas the B/Si atomic ratio shows an opposite varying tendency. By introducing moderate Ar flow, the B-doping efficiency is improved due to the crystallization and the enhanced dissociation of B2H6. The maximum values of dark conductivity (1.64 S cm-1) and carrier concentration (2.6 x 1019 cm-3) were obtained at the Ar flow of 100 sccm. Furthermore, detailed discussion has been made to analyze the influence of Ar dilution on the properties of the B-doped SiOx thin films. [ABSTRACT FROM AUTHOR]

A microwave plasma enhanced chemical vapor deposition (microwave PECVD) process has been investigated to deposit micro crystalline silicon films with a high growth rate from silane (SiH 4 ). A three-layer Bruggeman-Effective-Medium-Approximation (BEMA) model was developed to describe the complex structure of the grown films. The model was confirmed by Raman and spectroscopic ellipsometry measurements. In addition the surface evolution was characterized by AFM (Atomic Force Microscopy) and spectroscopic ellipsometry data. Particular emphasis is given to the correlation between the structural film properties and the deposition parameters. Besides chemical reactions, it is shown that ion bombardment plays an important role for the crystallinity of the grown silicon films. In the presence of ions, hydrogen radicals are able to etch silicon, which significantly improves the crystallinity of the deposited films. If just radicals are present, the deposited films become amorphous. [ABSTRACT FROM AUTHOR]

The effect of deposited a-Si layers with different layer stress on oxide precipitation was investigated in order to find out if intrinsic point defects affecting oxide precipitation are generated at the interface a-Si/Si and if possibly hydrogen affects the oxide precipitation. A thermal cycle of nucleation at 650 °C for 4 h or 8 h followed by stabilization at 780 °C for 3 h, and growth at 1000 °C for 16 h was applied. It was found that there are no signs for the injection of intrinsic point defects from the interface a-Si/Si into the Si substrate during the applied thermal treatment. However if a-Si is deposited on 1000 nm silicon oxide, deposited previously from TEOS in a plasma process, silicon self-interstitials seem to be injected from the interface silicon oxide/Si into the silicon substrate retarding oxide precipitation in the initial stage of nucleation annealing at 650 °C. There are also no signs of any impact of the layer stress on oxide precipitation or self-interstitial injection. The concentration of hydrogen in the layers can be controlled via the RF bias power. The hydrogen concentration is reduced markedly already during annealing at 650 °C. Part of the hydrogen diffuses into the silicon substrate and enhances oxide precipitation if its initial concentration in the layers is higher than 1.5 × 1022 cm−3. For a-Si deposited on 1000 nm silicon oxide, the enhancement effect appears for hydrogen concentrations in the layer higher than approximately 2.8 × 1022 cm−3. [ABSTRACT FROM AUTHOR]