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This paper presents a comprehensive analysis, carried out by the molecular dynamics (MD) simulations, of the vibrations of silicon nanowire (SiNW) resonators, having diverse applications including biological and medical fields. The chosen approach allows us to obtain a better understanding of the nanowire (NW) materials’ characteristics, providing a more detailed insight into the behavior of nanostructures, especially when the topic of interest is relevant to their dynamics, interatomic interactions, and atoms trajectories’ prediction. We first simulate a SiNW to study its frequency of vibrations using MD simulations. Then, we add a molecule of human immunodeficiency virus as an example to investigate the potential of the SiNW resonator for the detection of tiny bio-objects. The developed technique and its application to the detection of tiny objects, such as viruses, are discussed in the context of several key effects pertinent to the design of SiNW.

In this paper, we report morphology of silicon nanowires (Si-NWs) grown on various surfaces and patterned substrates using Vapor–Liquid–Solid (VLS) and Solid–Liquid–Solid (SLS) techniques. It is observed that the growth conditions are critical in controlling the dimensions of wires in both techniques. In addition to this, it is also demonstrated that Si-NWs are essentially different grown on Si or GaAs substrates. For growth of Si-NWs by VLS, Si powder was evaporated in a tube furnace under Ar flow while substrates were kept at different temperatures. In SLS, experimental conditions were identical except that no external source was used. Si-NWs thus grown showed dependence on the flow rate of Ar gas and the temperature of the substrate. Interestingly, instead of only radial nannowires (NWs), nanobelts and tapered NWs were also grown on patterned Au-catalyzed GaAs surface. In the end, the analysis on the basis of existing theories of NW growth is presented. Optical properties of Si-NWs are also briefly discussed.

We have grown metal catalyst free, straight Si nanowires (NWs) with high aspect ratio of about 130 on Si(100) substrate using radio frequency magnetron sputtering. Thin Si seed layer on thermally oxidized substrate was used for catalyst-free growth. Then Si deposition was done on that substrate using sputtering technique followed by heat treatment at different temperatures (900°C–1100°C). Sample heated at 1000°C results in straight, long, and uniform cylindrical shaped Si NWs with diameter 62–74 nm and length up to 8 μm, whereas sample heated above 1000°C transformed toward nanorods with larger diameter. However, no significant growth of Si NWs took place at 900°C. Sputter deposition technique provides an alternate fabrication route for Si NW synthesis. For comparison, we have also grown Au catalyst assisted Si NWs on Si(100) substrate by similar process. These nanowires also show similar morphology with diameter 48–65 nm and aspect ratio about 165. Growth mechanism and effect of growth temperatures on the structure and morphology of Si NWs are discussed.

Silicon nanowires (Si NWs) are promising candidates for field-effect transistor (FET) conduction channel. Planar configuration using a back gate is an easy way to study these devices. We demonstrate the possibility to build high performance FET using a simple silicidation process leading to high effective holes' mobility between 130 cm²⋅V^-1⋅s^-1 and 200 cm²⋅V^-1⋅s^-1 and good I_ON/I_OFF ratio up to 10⁵. Moreover we investigated the possibility to passivate the NWs using either a high-k dielectric layer or a thermal oxide shell around the NWs. This leads to a reduction of the hysteretic behavior during the gate voltage sweep from 30 V to 1 V depending on the material and the gate configuration.

We report on the sensitive detection of glucose using silicon nanowire array field-effect-transistor (SiNW-FET) upon illumination. The uniformly distributed and size-controlled SiNWs were fabricated by "top-down" approach. The fabricated SiNW-FET device was evaluated for detection of glucose in the range of 100–900 mg/dL. The SiNW-FET shows enhanced sensitivity of 0.988 ± 0.030 nA (mg/dl)^-1 upon illumination at 480 nm light as compared to without illumination as 0.486 ± 0.014 nA (mg/dL)^-1. The presented SiNW-FET device is fast, stable and sensitive to light as well as to bio analyte, and hence can be utilized as sensitive biological sensing platform.

The electron field emission (EFE) properties of vertically aligned arrays of silicon nanowires (SiNWs) grown from silicon substrate at different gold sputtering periods of 0s, 8s, 15s and 25s at a rate of 10nm/min by electroless metal deposition process were investigated. It has been observed that the transformation of silicon tips from irregular to highly dense and uniform cylindrical morphological nanostructures with an increase in Au sputtering periods. A significant enhancement in EFE properties of as-prepared arrays of SiNWs with the increase in Au sputtering periods is observed. The threshold fields for attaining current density of 0.1mA${\mathrm{\text{cm}}}^{-2}$ were decreased gradually as 32.38$\mathrm{\text{V}}\mu {\mathrm{\text{m}}}^{-1}$, 29.37$\mathrm{\text{V}}\mu {\mathrm{\text{m}}}^{-1}$ and 23.19$\mathrm{\text{V}}\mu {\mathrm{\text{m}}}^{-1}$ for the arrays of SiNWs synthesized from Si substrate by Au coating of 8s, 15s and 25s respectively. Moreover, from Fowler–Nordheim plot, the turn-on field is observed to decrease from 16.56$\mathrm{\text{V}}∕\mu \mathrm{\text{m}}$ for as-prepared to 8.77$\mathrm{\text{V}}∕\mu \mathrm{\text{m}}$ for 25s Au sputtered SiNW arrays. The effective work functions of the electron emitting array of SiNWs have been improved from 0.5meV to 0.1meV.

Silicon is widely studied as a high-capacity lithium-ion battery anode. However, the pulverization of silicon caused by a large volume expansion during lithiation impedes it from being used as a next generation anode for lithium-ion batteries. To overcome this drawback, we synthesized ultrathin silicon nanowires. These nanowires are 1D silicon nanostructures fabricated by a new bi-metal-assisted chemical etching process. We compared the lithium-ion battery properties of silicon nanowires with different average diameters of 100nm, 30nm and 10nm and found that the 30nm ultrathin silicon nanowire anode has the most stable properties for use in lithium-ion batteries. The above anode demonstrates a discharge capacity of 1066.0mAh/g at a current density of 300mA/g when based on the mass of active materials; furthermore, the ultrathin silicon nanowire with average diameter of 30nm anode retains 87.5% of its capacity after the 50th cycle, which is the best among the three silicon nanowire anodes. The 30nm ultrathin silicon nanowire anode has a more proper average diameter and more efficient content of SiO_x. The above prevents the 30nm ultrathin silicon nanowires from pulverization and broken during cycling, and helps the 30nm ultrathin silicon nanowires anode to have a stable SEI layer, which contributes to its high stability.

ZnO nanoneedles were deposited on the chemically etched silicon nanowires via simple low temperature hydrothermal process in this paper. The morphology, structure and optical properties were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), photoluminescence (PL), and Raman spectrum, respectively. The XRD pattern reveals a wurtzite structure for the ZnO nanoneedles. And SEM results show that the ZnO nanoneedles have a length of ∼ 400 nm with an average tip diameter of ∼ 5 nm and a base diameter of ∼ 50 nm. Meanwhile, the PL results show that the nanoneedles have wide band emission. Furthermore, the Raman results confirmed that the ultrafine nanoneedles have high surface area and surface defects. The wide band emission of ZnO nanoneedles suggests that it might serve as a potential host for white-light-emitting materials.

The graphene nanosheets have been deposited on silicon nanowires (SiNWs) at room temperature. SiNWs were grown by hot-wire chemical vapor process (HWCVP). A simple and room temperature approach known as electrophoretic deposition (EPD) process was adopted for the deposition of graphene sheets on SiNWs. GO sheets on SiNWs were converted to reduced graphene oxide (rGO) by photo-reduction method. EPD parameters were optimized to get a uniform coating of rGO on SiNWs. It was observed that the rGO deposition is greatly influenced by the deposition time and the applied voltage in the EPD process. rGO deposition was confirmed by FEG-SEM and FEG-TEM, and the reduction of GO to rGO was verified by Raman, UV–Vis and Fourier transform infrared (FTIR) spectroscopy.