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Dual Management of Electrons and Photons to Get High-Performance Light Emitting Devices Based on Si Nanowires and Si Quantum Dots with Al <sub/>2</sub> O <sub/>3</sub> -Ag Hybrid Nanostructures
摘要： Silicon quantum dot (Si QD)-based light emitting devices are fabricated on Si nanowire (Si NW) arrays. Through inserting Al2O3-Ag hybrid nanostructures (Al2O3-Ag HNs) between Si NWs and Si QDs, both photoluminescence (PL) and electroluminescence (EL) are remarkably enhanced compared to the control sample. The PL enhancement can be mainly attributed to passivation effect of Al2O3 to p-type Si NWs and enlarged absorption cross-section due to the local surface plasmon resonance effect of Ag nanoparticles. The EL intensity is enhanced by 14.9-fold at the same injection current under a lower applied voltage, which may result from the high injection efficiency of electrons and the promoted waveguide effect of nanowire structures with Al2O3-Ag HNs. It is demonstrated that light emitting device performances can be well improved by careful management of both electrons and photons via controlling the interface conditions of Si NWs/Si QDs.
关键词： hybrid nanostructures,silicon nanowires,light emitting devices,silicon quantum dots
更新于2025-11-21 11:01:37
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Silicon nanowire luminescent sensor for cardiovascular risk in saliva
摘要： Cardiovascular diseases are some of the today major cause of death in the world. C-reactive protein (CRP) is well known as the main biomarker related to cardiovascular risk and heart attack occurrence. The standard CRP analyses are performed in a hospital or in a biochemical laboratory with blood analysis after a long chemical and labelling preparation that require expert personnel. In this scenario, a health care analysis that can be performed by the same patient at his own home appears extremely revolutionary. In this paper, the study of an innovative sensing platform based on the luminescence at room temperature of silicon nanowires (NWs) is reported. This NWs sensor is label-free and does not require a chemical treatment of the analyte, is strongly selective to the CRP demonstrating a femtomolar limit of detection and a wide operating range. This proposed silicon sensing platform can be realized with an industrial compatible approach and permits to reveal the strategic CRP level in saliva in order to prevent a heart attack, with great advantages for the patient.
关键词： Cardiovascular risk,Saliva,C-reactive protein,Silicon nanowires,Luminescent sensor
更新于2025-11-21 11:01:37
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Growth and Self-Assembly of Silicon–Silicon Carbide Nanoparticles into Hybrid Worm-Like Nanostructures at the Silicon Wafer Surface
摘要： This work describes the growth of silicon–silicon carbide nanoparticles (Si–SiC) and their self-assembly into worm-like 1D hybrid nanostructures at the interface of graphene oxide/silicon wafer (GO/Si) under Ar atmosphere at 1000 °C. Depending on GO film thickness, spread silicon nanoparticles apparently develop on GO layers, or GO-embedded Si–SiC nanoparticles self-assembled into some-micrometers-long worm-like nanowires. It was found that the nanoarrays show that carbon–silicon-based nanowires (CSNW) are standing on the Si wafer. It was assumed that Si nanoparticles originated from melted Si at the Si wafer surface and GO-induced nucleation. Additionally, a mechanism for the formation of CSNW is proposed.
关键词： nanoparticles,thermal reduction,silicon carbide,graphene oxide,self-assembly,silicon,nanowires
更新于2025-09-23 15:23:52
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Quasi-one-dimensional silicon nanostructures for gas molecule adsorption: a DFT investigation
摘要： Porous structures offer an enormous surface suitable for gas sensing, however, the effects of their quantum quasi-confinement on their molecular sensing capacities has been seldom studied. In this work the gas-sensing capability of silicon nanopores is investigated by comparing it to silicon nanowires using first principles calculations. In particular, the adsorption of toxic gas molecules CO, NO, SO2 and NO2 on both silicon nanopores and nanowires with the same cross sections was studied. Results show that sensing-related properties of silicon nanopores and nanowires are very similar, suggesting that surface effects are predominant over the confinement. However, there are certain cases where there are remarked differences between the nanowire and porous cases, for instance, CO-adsorbed nanoporous silicon shows a metallic band structure unlike its nanowire counterpart, which remains semiconducting, suggesting that quantum quasi-confinement may be playing an important role in this behaviour. These results are significant in the study of the quantum phenomena behind the adsorption of gas molecules on nanostructure’s surfaces, with possible applications in chemical detectors or catalysts.
关键词： Sensing,Chemical sensors,Silicon nanowires,Density functional theory,Molecule adsorption,Porous silicon
更新于2025-09-23 15:23:52
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Nanoparticle Emissions from Metal-Assisted Chemical Etching of Silicon Nanowires for Lithium Ion Batteries
摘要： As one of the most promising anode materials for high-capacity lithium ion batteries (LIBs), silicon nanowires (SiNWs) have been studied extensively. The metal-assisted chemical etching (MACE) is a low-cost and scalable method for SiNWs synthesis. Nanoparticle emissions from the MACE process, however, are of grave concerns due to their hazardous effects on both occupational and public health. In this study, both airborne and aqueous nanoparticle emissions from the MACE process for SiNWs with three sizes of 90 nm, 120 nm, and 140 nm are experimentally investigated. The prepared SiNWs are used as anodes of LIB coin cells, and the experimental results reveal that the initial discharge and charge capacities of LIB electrodes are 3636 and 2721 mAh g-1 with 90 nm SiNWs, 3779 and 2712 mAh g-1 with 120 nm SiNWs, and 3611 and 2539 mAh g-1 with 140 nm SiNWs. It is found that, for 1 kW h of LIB electrodes, the MACE process for 140 nm SiNWs produces a high concentration of airborne nanoparticle emissions of 2.48 × 109 particles/cm3; the process for 120 nm SiNWs produces a high mass concentration of aqueous particle emissions, with a value of 9.95 × 105 mg/L. The findings in this study can provide experimental data of nanoparticle emissions from the MACE process for SiNWs for LIB applications, and can help the environmental impact assessment and life cycle assessment of the technology in the future.
关键词： Lithium ion batteries (LIBs),Metal-assisted chemical etching (MACE),Nanoparticle emissions,Silicon nanowires (SiNWs)
更新于2025-09-23 15:23:52
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Nanostructuring Strategies To Increase the Photoelectrochemical Water Splitting Activity of Silicon Photocathodes
摘要： Photoelectrochemical water splitting is a promising route for sustainable hydrogen production. Herein, we demonstrate a photoelectrode motif that enables a nanostructured large-surface area electrocatalyst without requiring a nanostructured semiconductor surface with the goal of promoting electrocatalysis while minimizing surface recombination. We compare the photoelectrochemical H2 evolution activity of two silicon photocathode nanostructuring strategies: (1) direct nanostructuring of the silicon surface and (2) incorporation of nanostructured zinc oxide to increase the electrocatalyst surface area on planar silicon. We observed that silicon photocathodes that utilized nanostructured ZnO supports outperformed nanostructured silicon electrodes by ～50 mV at open circuit under 1 sun illumination and demonstrated comparable electrocatalytic activity.
关键词： photocathodes,silicon nanowires,hydrogen evolution,molybdenum disulfide,zinc oxide nanowires,photoelectrochemical water splitting
更新于2025-09-23 15:22:29
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Optical properties of ZnO deposited by atomic layer deposition (ALD) on Si nanowires
摘要： In this work, we report proof-of-concept results on the synthesis of Si core/ ZnO shell nanowires (SiNWs/ZnO) by combining nanosphere lithography (NSL), metal assisted chemical etching (MACE) and atomic layer deposition (ALD). The structural properties of the SiNWs/ZnO nanostructures prepared were investigated by X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopies. The X-ray diffraction analysis revealed that all samples have a hexagonal wurtzite structure. The grain sizes are found to be in the range of 7–14 nm. The optical properties of the samples were investigated using reflectance and photoluminescence spectroscopy. The study of photoluminescence (PL) spectra of SiNWs/ZnO samples showed the domination of defect emission bands, pointing to deviations of the stoichiometry of the prepared 3D ZnO nanostructures. Reduction of the PL intensity of the SiNWs/ZnO with the increase of SiNWs etching time was observed, depicting an advanced light scattering with the increase of the nanowire length. These results open up new prospects for the design of electronic and sensing devices.
关键词： nanosphere lithography (NSL),atomic layer deposition (ALD),Silicon nanowires (SiNWs),metal-assisted chemical etching (MACE),ZnO
更新于2025-09-23 15:21:21
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N-type silicon nanowires prepared by silver metal-assisted chemical etching: Fabrication and optical properties
摘要： This paper reports the fabrication of silicon nanowires (SiNWs) by silver (Ag) metal-assisted chemical etching (MACE) method. N-type Si (100) wafers, doped with phosphorus with the resistivity from 1 ÷ 10 Ω×cm, were selected for sample preparation. Ag particles of about 30 nm in diameter, which were used as the catalytic metal, were aggregated on the surface of the Si wafer immersed in HF (4.6 M) and AgNO3 solution, with the variation concentration of 15–35 mM, for one minute. Consequently, the Si wafers covered with Ag particles were etched in HF (4.8 M) and H2O2 (0.4 M) solution for the formation of vertically aligned SiNWs. We found that the size and density of SiNWs decreased with the increase of AgNO3 concentration. After a delay time of about 30–40 min, the SiNWs growth depended linearly on the etching time. The light emission from the prepared SiNWs observed at room temperature was well resolved with two bands at around 450 nm (~ 2.75 eV) and 700 nm (~ 1.77 eV). The origins of the two emission bands and the comparative aspects are presented and discussed.
关键词： Chemical etching,Silicon nanowires,Photoluminescence,Metal assisted
更新于2025-09-23 15:21:01
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Controllable Patterning of Hybrid Silicon Nanowire and Nanohole Arrays by Laser Interference Lithography
摘要： Metal-assisted chemical etching (MACE) is a cost-effective method to fabricate Si nanostructures including silicon nanowires (SiNWs) and silicon nanoholes (SiNHs). However, the preparation of metallic template for MACE would require complex experimental conditions including strict cleaning process and multiple steps. In our study, we applied superlens-enhanced laser interference lithography to directly fabricate complicated metallic patterns and then used MACE to obtain hybrid SiNW and SiNH arrays. Ag films were firstly deposited on Si substrates, and then a 1064 nm high power laser source was utilized to generate two-beam interference electric fields. Since Ag molecules are very sensitive to any input energy change, they tend to break up or aggregate and form different Ag patterns which have a specific energy threshold in order to lower its free energy. By manipulating the distribution of input electric field, we are able to obtain complicated metallic patterns and their corresponding Si nanostructures with feature sizes that range from tens of nanometers to several micrometers.
关键词： silicon nanowires and silicon nanoholes,silicon nanostructures,nanofabrication,metal-assisted chemical etching
更新于2025-09-23 15:19:57
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One Step Deposition of PEDOT–PSS on ALD Protected Silicon Nanowires: Toward Ultrarobust Aqueous Microsupercapacitors
摘要： Herein, we propose a fast and simple deposition method of a highly robust pseudocapacitive material based on a straightforward drop-cast of a commercial PEDOT:PSS solution onto 3 nm alumina-coated silicon nanowires. The composite material produced (PPSS-A@SiNWs) displays remarkable capacitive behavior with a specific capacitance of 3.4 mF·cm?2 at a current density of 2 A·g?1 in aqueous Na2SO4 electrolyte. Moreover micro-supercapacitor (MSC) devices based on this material exhibits outstanding lifetime capacity retaining 95% of its initial capacitance after more than 500 000 cycles at a current density of 0.5 A·g?1, a specification which exceeds by far most of the stability of conducting polymers previously reported in the literature. In term of pure energy storage performances, the system is able to reach excellent specific energy and power values of 8.2 mJ·cm?2 and of 4.1 mW·cm?2, respectively, at a high current density of 2 A·g?1. Results are systematically compared to both the state-of-the-art silicon based aqueous on-chip supercapacitors and to that of the pristine alumina-coated silicon nanowires (A@SiNWs) to highlight the contribution of the conductive PEDOT:PSS polymer (PPSS in this study). Hence, the aforementioned one-step deposition represents a simple, cheap and scalable method to thoroughly increase the cycling stability of a well-known conductive polymer, PEDOT?PSS, while drastically increasing the electrochemical performances of an existing technology, the Si NW-based MSCs using aqueous electrolytes.
关键词： microsupercapacitors,silicon nanowires,conductive polymer,aqueous electrolyte,ultrarobust,nanocomposite
更新于2025-09-19 17:15:36