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Low-threshold field emission is the intrinsic property for nanocarbon materials. Emission characteristics of planar field cathodes with carbon nanotubes (CNT) deposited from solution to Si, Al, Pd substrates were studied. The field emission threshold value for horizontally aligned CNT was found as low as 4 V/μm. However, the field enhancement in these samples is negligible (<10). We propose to...
In this paper, nanostructured materials based both on silica and silicon, are studied in order to obtain new materials with both large Raman gain coefficients and spectral bandwidth. In particular, silica-niobia based glasses have been characterized by linear Raman spectroscopy, while amorphous silicon nanoparticles and in silicon micro- and nano-crystals have been characterized by Stimulated Raman...
Nonlinear optics at nanoscale is an intriguing research field of great significance from both fundamental and applicative point of view. In this paper, the phenomena of stimulated Raman scattering in both nanostructured silica based materials and nanostructured silicon based materials are investigated and discussed.
As the future of Moore's law appears uncertain, Electronics is being reinvented with a broader focus on flexible electronics, bioelectronics, and energy-harvesting. In this regard, a material based on nanonets of Carbon Nanotubes or Si/ZnO/SiGe Nanowires have been used as channel materials for thin-film transistors for flexible/transparent electronics, as sensor elements for label-free bio-sensors,...
As photovoltaics (PV) cost reduction driven by economies of scale is approaching a limit, technological breakthroughs are likely to become again the next driver for further growth. In this paper, we review the most significant photovoltaic (PV) device technologies. First, commercially available cells and modules are briefly surveyed, focusing on the innovations that have recently reached the market,...
Solid propellants are used in various flight and underwater systems as well as in propulsion platforms. Micromachining, microelectromechanical systems (MEMS) and automatic dispensing of high-energy-density nanoenergetic materials are examined for current and next generation of application-specific flight and underwater platforms. The integrated MEMS-technology microthrusters with the optimized-by-design...
The methodology suggested in this research provides the great possibility of creating nanostructures composed of various materials, such as soft polymer, hard polymer, and metal, as well as Si. Such nanostructures are required for a vast range of optical and display devices, photonic components, physical devices, energy devices including electrodes of secondary batteries, fuel cells, solar cells,...
We present an accurate 3D reconstruction method for silicon micro/nanostructures with high aspect ratio, that was developed and implemented using a dual beam (Focused ion beam and scanning electron microscopy (FIB-SEM)) tomography. Black Silicon (BSi) samples were processed by alternating steps of FIB etching and SEM imaging, that allow obtaining sequential cross section images of the sample, including...
In the present paper, the reduced spectral reflectance properties of silicon micro/nanostructures are studied. In the aim of implementing a predictive reflectance simulation model based on surface topography, an alternative design method of an equivalent unit cell is proposed, where the dimensions and shape are determined based on statistical parameters of the sample topography. A good concordance...
Nonlinear optics at nanoscale is a recent fascinating research field. Among the numerous nonlinear optics phenomena, due to its significant implications from both fundamental and applicative point of view, stimulated Raman scattering is one of the most interesting. In this paper, the observations of stimulated Raman scattering in silicon nano-particles, at the wavelengths of interest for telecommunications,...
Although the introduction of nanostructures into thermoelectric materials is one of key technology for enhancement in thermoelectric conversion efficiency, a technique for characterizing the nanometer-scale materials is required. With the aim of evaluating Seebeck coefficient of nanostructured thermoelectric materials, we propose a new technique by Kelvin- probe force microscopy (KFM) which gives...
Nonlinear optics at nanoscale is a recent fascinating research field. Among the numerous nonlinear optics phenomena, due to its significant implications from both fundamental and applicative point of view, stimulated Raman scattering is one of the most interesting. In this paper, the observations of stimulated Raman scattering in silicon nano-particles, at the wavelengths of interest for telecommunications,...
In this study, the Al-doped ZnO (AZO) nanorods were synthesized on silicon substrate by the hydrothermal process. The SiO2/silicon substrate was submerged horizontally in 0.06M mixture solution of zinc nitrate hexahydrate (Zn(NO3)2·6H2O), diethylenetriamine (DETA), and doped the solution of aluminium nitrate, nonahydrate (Al(NO3)3·9H2O) at about 90°C for 4h. It has been shown that the ZnO nanorods...
Thin-film crystalline photovoltaic (PV) cell is a trend for future PV with its potential to achieve low cost and high efficiency. Concerning material utilization efficiency, we propose a method with a fast manufacturing method of thin crystalline Si by chemical solution. To obtain the highest efficiency of material utilization, experiments with different H2O2/HF ratio are conducted, where related...
High efficiency thin film silicon solar cells consist of multiple junctions with hydrogenated amorphous silicon, silicon germanium alloys, and nanocrystalline silicon (nc-Si:H) absorbers. Uniformity over large areas is challenging for nc-Si:H and an accurate method of mapping material quality via a technique like ex situ spectroscopic ellipsometry (SE) is desirable. In situ, real time SE (RTSE) measurements...
Generally, as operating frequency becomes higher, magnetic components get smaller and lighter. However, higher frequency leads to larger core loss and copper loss. Therefore, the appropriate material of the core and operating frequency needs to be determined to realize well-designed magnetic components. So far, a silicon steel sheet has been used in the low frequency range for large-capacity conversion...
To investigate the relation between optical property and size of the nano structure, the band structures, density of states, and optical properties of series nano structures embedded in SiO2 were calculated using the density functional theory-plane waves(DFT-PW) of first-principles method. The results show, the intermediate levels of Ge and Si nanostructure are at about 3.3 eV and 4.3 eV above Fermi...
We demonstrate selectively-grown GaAs nano/micro structures on silicon substrates by molecular beam epitaxy. Hexagonal or rectangular shaped GaAs crystals, depending on the orientation of the silicon substrate, were formed inside the silicon-dioxide-masked nanoholes at 630°C. Clear facets, which are the low-energy {011} planes, indicate single-crystalline nature of the growth. GaAs/InAs/GaAs structure...
The physics of instability of thin film Si solar cells is strongly dependent upon the nature of the Si, whether it is amorphous or nano(also called micro)crystalline. The amorphous phase is much more unstable than the nanocrystalline phase. The instability of the amorphous Si , which is really an alloy of Si and H, and H, is primarily due to the poor microstructure of the material. The amorphous material...
The limiting performance and reliability of metal-oxide-semiconductor (MOS) devices is determined by intrinsic bonding defects. These are primarily O-atom vacancies. A universal model, developed initially for (i) nano-crystalline transition metal (TM) Oxides is extended to O-vacancies in (i) non-crystalline SiO2 and Si oxynitride alloys. Differences between electron injection into, and trapping ay...
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