Explore the vast range of titles available.

Silicon and silicon-based materials are among the important modern materials with application in many fields of technology from electronics to energy materials. For some applications, for example the use of Si in Li-ion batteries, nanometer-sized dimensions are required. A cost-effective, environmentally sustainable, scalable, and versatile formation of functional Si films and materials is therefore of large interest. In this work, we report on the electrodeposition of amorphous silicon-based films onto planar and onto nanoporous copper substrates using different organic electrolytes. The morphology and composition of the Si-based coatings are dependent on the solvent used for electrodeposition. Acetonitrile, as a low viscosity solvent, leads to the faster formation of thicker, mostly metallic, and homogeneous electrodeposited Si films. Propylene carbonate, a higher-viscosity solvent generates thinner and more heterogeneous coatings. The Si electrodeposition presented in this work could be transferred onto other complex substrate morphologies, with potential applications in the fields of heterogeneous photocatalysis or energy storage. Graphical Abstract

Optical parameters of porous silicon films of doped 100-oriented silicon substrate fabricated by electrochemical etching are investigated. The photoluminescence and ellipsometry measurements were realized under the effect of etching current densities and contact times. The ellipsometry is simulated using a model of multilayer structures that allows the determination of the thickness, refractive index, penetration factor, extinction coefficient, absorption coefficient, and porosity of the silicon (PS) layer. Our results have shown that agreement is obtained between the PL measurements, represented by the integrated PL intensity, together with the FTIR and SEM measurements, represented by the thickness and the porosity of the porous layers, for etching time and varying current density. The absorption coefficient decreased as a function of the current density value with increasing porosity, and the penetration factor is an increasing function with current density. We also note that the data presented in this work are more promising for the development of layers for photovoltaic applications.

Silicon has been irreplaceable for a long time due to its well-estiblished design and fabrication in the field of Micro-Electro-Mechanical System (MEMS). However, it has poor tribological properties, which limits the further application of actuators (with relative motion) based MEMS. First, the amorphous silicon (a-Si) coatings were prepared on silicon substrates and high-speed steel (HSS) substrates by plasma enhanced chemical vapor deposition, and the relationships between mechanical properties and tribological performance were also systematically discussed. The wear rate of a-Si film on HSS has decreased significantly (decreased by 81.55%) compared with a-Si coating on silicon, which can be attributed to the larger elastic modulus and hardness of a-Si on the HSS matrix. Then, tungsten disulfide (WS 2 ) nanoflake coatings with low interlayer shear stress were successfully prepared on the amorphous silicon (a-Si) coatings by the drop-casting method, forming a WS 2  + a-Si coating to enhance the tribological properties. Combined with first-principles simulations and the characterization of the wear scar morphology, the macro-scale sliding friction of this composite coating against the Al 2 O 3 ceramic ball was investigated in ambient air. The results indicated that the introduction of WS 2 nanoflakes reduces the coefficient of friction (CoF) from 0.5 to 0.08. The reduction in CoF could be attributed to the in-situ formation of WS 2 lubricating transfer film on the wear scar of the ball and the WS 2 heterogeneous interface on a-Si film, leading to asymmetric contact between the friction pairs, which in turn triggers low and stable friction.

The uniqueness of the properties of silicon–carbon and silicon–metal–carbon films, which are representatives of the nanocrystalline and amorphous classes of carbon allotropes, leads to a wide range of areas of their possible applications. In this study, the dynamics of the development of technologies for obtaining and expanding the areas of application of silicon–carbon and silicon–metal–carbon films is analyzed. Thus, the elasticity, the mechanical strength (1500–3000 kg/mm 2 ), and the chemical stability of films ensure the effectiveness of their applications as passivating coatings. Thermal conductivity and a high emissivity factor (0.8), high elastic-modulus values (9 × 10 11 N/m 2 ), the high resistivity of silicon–carbon films (10 5 –10 8  Ohm cm), and their transparency to electromagnetic radiation (up to frequencies of several tens of gigahertz) allow them to be used in broadband radio-frequency devices as moveable elements (beams, bridges, membranes) of microelectromechanical system (MEMS) switches and varactors. The thermal resistance (up to 600°C in an open system), the rather high electrical conductivity (the specific resistance is ~10 –5 Ohm cm), and the high emissivity of the films make it possible to form silicon–metal–carbon films based on heating-type broadband radiators with a radiation spectrum depending on the film temperature in the range of 2–14 μm. Phase transformations of the amorphous silicon–carbon film into a graphene film, which are carried out by means of high-temperature annealing in vacuum in the presence of a catalyst, allow the formation on this basis of control electrodes with low grid current losses (no more than 5%) in vacuum emission devices of high-power microwave electronics, as well as the functional layer of a multilayer heterostructure of a field-emission medium for moveable cold cathode-grid units. The revealed effect of self-modulation of the phase and elemental composition of a silicon–metal–carbon film in the growth direction is of not only applied but also fundamental interest.

To achieve high-quality sputtered amorphous silicon (a-Si) thin films with low argon (Ar) working gas atom content and high film density, the effects of on Ar gas content and film density is investigated. Here, is Ar working pressure and is target-to-substrate. The findings from this work indicate that the Ar gas content in the films primarily arises from highly energetic reflected Ar ions that bombard growing a-Si thin films at low values (< 50 Pa·mm). As increases, a monotonic decrease in film density is observed. This results well correlates with the declining average energy of sputtered silicon atoms reaching the substrate. Optimal conditions for fabricating sputtered a-Si thin films with both low Ar content and high film density were identified within the range of 30–40 Pa·mm. This research could provide valuable insights for researchers seeking to optimize the balance between low working gas content and high film density in sputtered thin films. Graphical Abstract

A silicon-nanostructured array coating on silicon film (SAS film) is designed based on the plasmonic optical tweezer and demonstrated for optical trapping and manipulation of nanospheres with negligible impact on the local thermal conditions. The electric field enhancement, optical force, and trapping potential of the SAS film are investigated by the finite element method. The trapping position is affected by the incident light wavelength, structure of the nanoarray, and refractive index of the nanospheres. The presence of four energy wells around the nanoarray suggests that it is possible to trap multiple nanoparticles. Moreover, the circularly polarized light, Gaussian beam, and silicon nanoarray facilitate the trapping of nanoparticles. This study showcases the potential of SAS film as optical tweezers to capture nanoparticles for the development of nanophotonic devices.

The present manuscript describes the fabrication of microcrystalline silicon (µc-Si) thin films at room temperature using the ionized physical vapor deposition (iPVD) process. The iPVD chamber incorporates a planar DC magnetron and an additional RF coil to generate an intermediate dense plasma region between the target and the substrate. The intermediate dense plasma enhances the ionization of sputtered neutral Si atoms before deposition in the iPVD process. This process greatly impacts the structural, morphological, and optical characteristics of the Si thin films. X-ray diffraction (XRD) reveals that conventional PVD produces an amorphous Si thin film, while iPVD yields a µc-Si thin film with peaks at 28.5° and 47.3°, corresponding to the (111) and (220) planes of Si. Raman spectroscopy confirms the microcrystalline nature of the Si thin film, showing approximately 70% crystallinity in the iPVD process. FESEM images display a granular structure for PVD and a cauliflower-like structure for the iPVD process. AFM images indicate a significant reduction in surface roughness for iPVD films compared to the PVD process. UV-Visible absorption spectroscopy shows that the optical band gap (Eg) decreases from (1.7 ± 0.08) eV to (1.4 ± 0.05) eV while shifting from the PVD to iPVD process.

Although laser-produced micro-/nano-structures have been extensively studied, the effects of the initial surface conditions on the formed micro-/nano-structures have rarely been investigated. In this study, through nanosecond pulsed laser irradiation of unpolished and polished amorphous silicon films, entirely different surface characteristics were observed. The effects of laser irradiation parameters, such as repetition frequency, beam overlap ratio, and scanning velocity, on the surface characteristics were investigated, followed by the characterization of surface roughness, energy-dispersive X-ray spectroscopy, and Raman spectroscopy of the irradiated surfaces. For the unpolished surface, novel micro-protrusions were generated after laser irradiation, whereas no such micro-protrusions were formed on the polished surface. The experimental results indicated that the height of the micro-protrusions could be tuned using laser irradiation parameters and that laser irradiation promoted the crystallization of the amorphous silicon film. Moreover, the formation mechanism of the micro-protrusions was linked to fluctuations of the solid–liquid interface caused by continuous laser pulse shocks at higher repetition frequencies. The findings of this study suggest important correlations between the initial surface conditions and micro-/nano-structure formation, which may enhance our fundamental understanding of the formation of micro-/nano-structures.

In this paper, we present a one-stage method for fabricating hybrid metal-dielectric nanostructures without the use of complex and expensive lithographic processes. The formation of arrays of nanoparticles occurs in the process of irradiation of a two-layer gold-silicon film with simultaneous mixing of materials. In this work, the internal structure of the obtained nanoparticles was studied using the methods of transmission scanning electron microscopy and energy-dispersive X-ray spectroscopy, and their broadband photoluminescence in the range of 450 - 900 nm was also demonstrated. These structures are promising as a source of radiation for optical measurements in lab-on-a-chip devices, which was shown by measuring the transmission spectrum of the Rhodamine B dye as an example.

Material failure is the main obstacle in fulfilling the potential of electrodes in lithium batteries. To date, different failure phenomena observed experimentally in various structures have become challenging to model in numerical simulations. Moreover, their mechanisms are not well understood. To fill the gap, here we develop a coupled chemo-mechanical model based on peridynamics, a particle method that is suitable for simulating spontaneous crack growth, to solve the fracture problems in silicon thin films due to lithiation/delithiation. The model solves mechanical and lithium diffusion problems, respectively, and uses a coupling technique to deal with the interaction between them. The numerical examples of different types of Si films show the advantage of the model in this category and well reproduce the fracture patterns observed in the experiments, demonstrating that it is a promising tool in simulating material failure in electrodes.