共查询到20条相似文献,搜索用时 15 毫秒
1.
Si heterojunction solar cells were fabricated on p-type single-crystal Si (sc-Si) substrates using phosphorus-doped Si nanocrystals (Si-NCs) embedded in SiNx (Si-NCs/SiNx) films as emitters. The Si-NCs were formed by post-annealing of silicon-rich silicon nitride films deposited by electron cyclotron resonance chemical vapor deposition. We investigate the influence of the N/Si ratio in the Si-NCs/SiNx films on their electrical and optical properties, as well as the photovoltaic properties of the fabricated heterojunction devices. Increasing the nitrogen content enhances the optical gap E04 while deteriorating the electrical conductivity of the Si-NCs/SiNx film, leading to an increased short-circuit current density and a decreased fill factor of the heterojunction device. These trends could be interpreted by a bi-phase model which describes the Si-NCs/SiNx film as a mixture of a high-transparency SiNx phase and a low-resistivity Si-NC phase. A preliminary efficiency of 8.6% is achieved for the Si-NCs/sc-Si heterojunction solar cell. 相似文献
2.
Pablo A. Fiorito Fernanda F.C. Bazito Gerard Froyer Roberto M. Torresi 《Electrochimica acta》2008,53(25):7396-7402
The electroformation of silicon oxide was performed in two room temperature ionic liquids (RTIL), 1-butyl-3-methyl-imidazolium bis(trifluoromethane sulfonyl) imide (BMITFSI) and N-n-butyl-N-methylpiperidinium bis(trifluoromethane sulfonyl) imide (BMPTFSI). This phenomenon was studied by electrochemical techniques and it was observed that the oxide growth follows a high-field mechanism. X-ray Photoelectron Spectroscopy experiments have shown that a non-stoichiometric oxide film was formed, related to the low water content present in both RTILs (<30 ppm). The roughness values obtained by using AFM technique of the silicon surface after etching with HF was 1.5 nm (RMS). The electrochemical impedance spectroscopy at low frequencies range was interpreted as a resistance in parallel with a CPE element, the capacitance obtained was associated with the dielectric nature of the oxide formed and the resistance was interpreted considering the chemical dissolution of the oxide by the presence of the TFSI anion. The CPE element was associated with the surface roughness and the very thin oxide film obtained. 相似文献
3.
Composite silicon film, which is composed of silicon nanowires, Si-Au eutectic and Si particles as the melding spots, was prepared as anode for lithium ion batteries by a special secondary deposition process with vapor-liquid-solid (VLS) mechanism. Au-Si eutectic particles act as the melding spots between silicon nanowires. An attractive electrochemical performance with 88% of the coulombic efficiency in the first cycle was obtained in the charge-discharge tests. The connection among silicon nanowires by dispersed Si-Au particles is the key factor for the enhancement of its electrochemical reversibility. 相似文献
4.
We demonstrated a novel, simple, and low-cost method to fabricate silicon nanowire (SiNW) arrays and silicon nanohole (SiNH) arrays based on thin silver (Ag) film dewetting process combined with metal-assisted chemical etching. Ag mesh with holes and semispherical Ag nanoparticles can be prepared by simple thermal annealing of Ag thin film on a silicon substrate. Both the diameter and the distribution of mesh holes as well as the nanoparticles can be manipulated by the film thickness and the annealing temperature. The silicon underneath Ag coverage was etched off with the catalysis of metal in an aqueous solution containing HF and an oxidant, which form silicon nanostructures (either SiNW or SiNH arrays). The morphologies of the corresponding etched SiNW and SiNH arrays matched well with that of Ag holes and nanoparticles. This novel method allows lithography-free fabrication of the SiNW and SiNH arrays with control of the size and distribution. 相似文献
5.
Liubov A Osminkina Vladimir A Sivakov Grigory A Mysov Veronika A Georgobiani Ulyana А Natashina Florian Talkenberg Valery V Solovyev Andrew A Kudryavtsev Victor Yu Timoshenko 《Nanoscale research letters》2014,9(1):463
Evaluation of cytotoxicity, photoluminescence, bio-imaging, and sonosensitizing properties of silicon nanoparticles (SiNPs) prepared by ultrasound grinding of porous silicon nanowires (SiNWs) have been investigated. SiNWs were formed by metal (silver)-assisted wet chemical etching of heavily boron-doped (100)-oriented single crystalline silicon wafers. The prepared SiNWs and aqueous suspensions of SiNPs exhibit efficient room temperature photoluminescence (PL) in the spectral region of 600 to 1,000 nm that is explained by the radiative recombination of excitons confined in small silicon nanocrystals, from which SiNWs and SiNPs consist of. On the one hand, in vitro studies have demonstrated low cytotoxicity of SiNPs and possibilities of their bio-imaging applications. On the other hand, it has been found that SiNPs can act as efficient sensitizers of ultrasound-induced suppression of the viability of Hep-2 cancer cells. 相似文献
6.
Porous silicon microstructures were fabricated by applying potential steps through which both anodic and cathodic potentials were periodically applied to silicon wafers. The electrochemical behaviors of porous silicon layers were examined by performing polarization measurements, followed by analyzing the open-circuit potential (Eocp) and the reaction rate in terms of corrosion current density (jcorr). The surface morphologies and surface products of porous silicon were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). It was found that the values of Eocp and jcorr varied more significantly and irregularly during different polarization stages when the potentials were continuously applied to the wafer surface, while virtually unchanged after 2 min of periodic potential application. In addition, slower reaction rates were observed with applying potential steps, as indicated by smaller values of jcorr. The enhancement on refreshment of silicon surfaces by periodic potential polarization significantly accelerated the growth of porous silicon. The microstructures became more uniformed and better defined due to the improved passivating nature of wafer surfaces. 相似文献
7.
We present a simple strategy to reduce the writing time of electron beam lithography (EBL) by using a highly sensitive Shipley’s
UV-5 resist while reducing proximity effects by depositing a thin film of silicon dioxide (SiO2) on silicon substrate. It was found that a simple insertion of a thin SiO2 film greatly reduced proximity effects, thereby providing enhanced resolution and better pattern fidelity. To support this
conclusion, the bottom line width and sidewall slope of the developed pattern were analyzed for each substrate with different
film thickness. 相似文献
8.
《Journal of the European Ceramic Society》2006,26(15):3451-3458
The present study was undertaken to establish a methodology for character rising silicon carbide-based refractories, as detailed information is unavailable in the literature on this point. We analysed several types of silicon carbide refractories belonging to the non-oxide and composite families of refractories, characterising each component by different methods. The phases were characterised first by X-ray diffraction (XRD). The components were then chemically characterised by different methods, which included the wet method, X-ray fluorescence (XRF) spectrometry, coulometry and inductively coupled plasma optical emission spectrometry (ICP-OES). The best method for characterising each component was determined. The proposed methodology was validated using reference materials. 相似文献
9.
Maha Ayat Samia Belhousse Luca Boarino Noureddine Gabouze Rabah Boukherroub Mohamed Kechouane 《Nanoscale research letters》2014,9(1):482
In this work, we report the fabrication of ordered silicon structures by chemical etching of silicon in vanadium oxide (V2O5)/hydrofluoric acid (HF) solution. The effects of the different etching parameters including the solution concentration, temperature, and the presence of metal catalyst film deposition (Pd) on the morphologies and reflective properties of the etched Si surfaces were studied. Scanning electron microscopy (SEM) was carried out to explore the morphologies of the etched surfaces with and without the presence of catalyst. In this case, the attack on the surfaces with a palladium deposit begins by creating uniform circular pores on silicon in which we distinguish the formation of pyramidal structures of silicon. Fourier transform infrared spectroscopy (FTIR) demonstrates that the surfaces are H-terminated. A UV-Vis-NIR spectrophotometer was used to study the reflectance of the structures obtained. A reflectance of 2.21% from the etched Si surfaces in the wavelength range of 400 to 1,000 nm was obtained after 120 min of etching while it is of 4.33% from the Pd/Si surfaces etched for 15 min. 相似文献
10.
Daniel W Drumm Manolo C Per Akin Budi Lloyd CL Hollenberg Salvy P Russo 《Nanoscale research letters》2014,9(1):443
In the midst of the epitaxial circuitry revolution in silicon technology, we look ahead to the next paradigm shift: effective use of the third dimension - in particular, its combination with epitaxial technology. We perform ab initio calculations of atomically thin epitaxial bilayers in silicon, investigating the fundamental electronic properties of monolayer pairs. Quantitative band splittings and the electronic density are presented, along with effects of the layers’ relative alignment and comments on disordered systems, and for the first time, the effective electronic widths of such device components are calculated. 相似文献
11.
Investigation on the film surface and bulk properties of fluorine and silicon contained polyacrylate
A series of fluorine and silicon acrylic latexes have been prepared from acrylic monomers, 2,2,3,4,4,4-hexafluorobutyl acrylate (HFBA) and vinyltriethoxysilane (VTES) via emulsion polymerization. Morphology and particle size distribution were evaluated by transmission electron microscopy (TEM) and dynamic light scattering (DLS) methods. Surface properties of latex films were investigated in terms of ATR-FTIR spectrometry, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and water resistance measurement. It is indicated that fluorine content at the surface of fluorosilicone acrylic film decreased as the film forming temperature was increased. A high temperature favored silicon condensation at the film surface, which limited migration ability of fluorine chains. Fluorine segment contributed to surface hydrophobicity while silicon component was beneficial to improve water repellency of the film bulk. Silicon containing particles were more difficult to coalesce than fluorine acrylic particles due to the rigid crosslinked network derived from silanol crosslinking. 相似文献
12.
本文阐述了用氢氧化钾熔融分解样品,硅氟酸钾容量法测定硅块中硅含量,确定了测定的分析条件,在优化的分析条件下对分析方法进行验证,测定样品精密度和加标回收率,其精密度的相对标准偏差均小于0.4%,加标回收率为99.1%-101.3%。本方法简便、快速,数据准确可靠,适用于工业硅块品质的判断。 相似文献
13.
Muhammad Y Bashouti Kasra Sardashti Jürgen Ristein Silke Christiansen 《Nanoscale research letters》2013,8(1):41
Oxidation of silicon nanowires (Si NWs) is an undesirable phenomenon that has a detrimental effect on their electronic properties. To prevent oxidation of Si NWs, a deeper understanding of the oxidation reaction kinetics is necessary. In the current work, we study the oxidation kinetics of hydrogen-terminated Si NWs (H-Si NWs) as the starting surfaces for molecular functionalization of Si surfaces. H-Si NWs of 85-nm average diameter were annealed at various temperatures from 50°C to 400°C, in short-time spans ranging from 5 to 60 min. At high temperatures (T ≥ 200°C), oxidation was found to be dominated by the oxide growth site formation (made up of silicon suboxides) and subsequent silicon oxide self-limitation. Si-Si backbond oxidation and Si-H surface bond propagation dominated the process at lower temperatures (T < 200°C). 相似文献
14.
A new fabrication method is proposed to produce nanostructures on monocrystalline silicon based on the friction-induced selective etching of its Si3N4 mask. With low-pressure chemical vapor deposition (LPCVD) Si3N4 film as etching mask on Si(100) surface, the fabrication can be realized by nanoscratching on the Si3N4 mask and post-etching in hydrofluoric acid (HF) and potassium hydroxide (KOH) solution in sequence. Scanning Auger nanoprobe analysis indicated that the HF solution could selectively etch the scratched Si3N4 mask and then provide the gap for post-etching of silicon substrate in KOH solution. Experimental results suggested that the fabrication depth increased with the increase of the scratching load or KOH etching period. Because of the excellent masking ability of the Si3N4 film, the maximum fabrication depth of nanostructure on silicon can reach several microns. Compared to the traditional friction-induced selective etching technique, the present method can fabricate structures with lesser damage and deeper depths. Since the proposed method has been demonstrated to be a less destructive and flexible way to fabricate a large-area texture structure, it will provide new opportunities for Si-based nanofabrication. 相似文献
15.
Silicon quantum dots (Si QDs) attract increasing interest nowadays due to their excellent optical and electronic properties. However, only a few optoelectronic organic molecules were reported as ligands of colloidal Si QDs. In this report, N-vinylcarbazole - a material widely used in the optoelectronics industry - was used for the modification of Si QDs as ligands. This hybrid nanomaterial exhibits different spectroscopic properties from either free ligands or Si QDs alone. Possible mechanisms were discussed. This type of new functional Si QDs may find application potentials in bioimaging, photovoltaic, or optoelectronic devices. 相似文献
16.
The electrochemical deposition of polypyrrole (PPy) on p-Si(1 0 0) electrodes was investigated. The electrodeposition was performed in aqueous electrolyte solutions utilising cyclic voltammetry. Thin, adhesive, uniform PPy films were successfully deposited on p-Si(1 0 0) electrodes. The Si/PPy interface was characterised with infrared spectroscopic ellipsometry (IR-SE) and photoluminescence (PL) measurements to obtain information of a possible oxidation of the Si interface and charge carrier recombination at the interface, respectively. Very small amounts of interfacial silicon oxides have been found at the Si/PPy interface. PL measurements lead to the assumption that electrodeposition of PPy onto the Si electrodes generated only very few additional non-radiative recombination-active (nr) defects. Hence, polypyrrole is an excellent passivation of nr defects at the silicon surface. 相似文献
17.
New silicon-containing epoxy compounds were obtained by reacting a bisphenol-A type epoxy and an o-cresol-formaldehyde novolac type epoxy with diphenylsilandiol and triphenylsilanol, respectively. The reactions were performed with tin(II) chloride as a catalyst at 140-170 °C. With various feeding ratios of reactants, the epoxy compounds contained various silicon contents. The thermal stability and the flame retardant property of the cured epoxy resins were improved with this incorporation of silicon. Synergistic effects of phosphorus/silicon and nitrogen/silicon on enhancing limited oxygen index values were also observed for the epoxy resins from the silicon-containing epoxy compounds cured with phosphorus- and melamine-containing agents. 相似文献
18.
The electrochemical properties of metallurgical-grade silicon (MGS) and its native oxide (passive layer) were investigated using standard potentiostatic, potentiodynamic and impedance methods. The corrosion rate was found to reach up to 37 μm year−1 in undiluted hydrochloric acid. The passive oxide layer was found to thicken with time as well as with potential. Increasing the potential from −0.5 to 1.0 V vs. SHE increases the thickness of the passive layer from approximately 2 to 6 nm. The interfacial impedance data for MGS in contact with the electrolyte was modeled. The model takes into account the capacitive behaviour of the space charge region and passive film. Due to the non-ideal behaviour of the passive film, a constant phase element (CPE) was incorporated in the model. Extraction of Mott–Schottky plot data from the EIS tests showed that the passive layer on the surface of the MGS is a p-type semiconductor. Scanning electron microscopy was used to determine that the impurities in the silicon (mostly iron, aluminum and calcium) were located almost exclusively at grain boundaries. 相似文献
19.
ABSTRACT: Owing to their interesting electronic, mechanical, optical and transport properties, silicon nanowires (SiNWs) have attracted much attention, giving opportunities to several potential applications in nanoscale electronic, optoelectronic devices and silicon solar cells. For photovoltaic (PV) application, a superficial film of SiNWs could be used as an efficient antireflection coating (ARC). In this work, we investigate the morphological, optical and electronic properties of SiNWs fabricated at different etching time. Characterizations of the formed SiNWs films were performed using a Scanning Electron Microscope (SEM), UV-Vis-NIR spectrophotometer and Light-Beam-Induced-Current (LBIC) technique. The later technique was used to determine the effective diffusion length in SiNWs films. From LBIC investigations, we deduce that the homogeneity of the SiNWs film play a key role on the electronic properties. 相似文献
20.
Rachid Ouertani Abderrahmen Hamdi Chohdi Amri Marouan Khalifa Hatem Ezzaouia 《Nanoscale research letters》2014,9(1):574
In this work, we use a two-step metal-assisted chemical etching method to produce films of silicon nanowires shaped in micrograins from metallurgical-grade polycrystalline silicon powder. The first step is an electroless plating process where the powder was dipped for few minutes in an aqueous solution of silver nitrite and hydrofluoric acid to permit Ag plating of the Si micrograins. During the second step, corresponding to silicon dissolution, we add a small quantity of hydrogen peroxide to the plating solution and we leave the samples to be etched for three various duration (30, 60, and 90 min). We try elucidating the mechanisms leading to the formation of silver clusters and silicon nanowires obtained at the end of the silver plating step and the silver-assisted silicon dissolution step, respectively. Scanning electron microscopy (SEM) micrographs revealed that the processed Si micrograins were covered with densely packed films of self-organized silicon nanowires. Some of these nanowires stand vertically, and some others tilt to the silicon micrograin facets. The thickness of the nanowire films increases from 0.2 to 10 μm with increasing etching time. Based on SEM characterizations, laser scattering estimations, X-ray diffraction (XRD) patterns, and Raman spectroscopy, we present a correlative study dealing with the effect of the silver-assisted etching process on the morphological and structural properties of the processed silicon nanowire films. 相似文献