Sn Nanowires Research Articles

Nanometer‐Scale Modification and Welding of Silicon and Metallic Nanowires with a High‐Intensity Electron Beam

We demonstrate that a high-intensity electron beam can be applied to create holes, gaps, and other patterns of atomic and nanometer dimensions on a single nanowire, to weld individual nanowires to form metal-metal or metal-semiconductor junctions, and to remove the oxide shell from a crystalline nanowire. In single-crystalline Si nanowires, the beam induces instant local vaporization and local amorphization. In metallic Au, Ag, Cu, and Sn nanowires, the beam induces rapid local surface melting and enhanced surface diffusion, in addition to local vaporization. These studies open up a novel approach for patterning and connecting nanomaterials in devices and circuits at the nanometer scale.

Single-crystalline nanotubes of IIB-VI semiconductors

Wurtzite-type CdS and CdSe nanotubes have been grown via a Sn nanowire-templated route under thermal annealing. The tubes are structurally uniform and defect-free single crystals, and partially or completely filled with Sn nanowires; most of the tubes display pin-like structures showing significant tapering along their axes. Cathodoluminescence spectra reveal that CdS and CdSe nanotubes have profound emission peaks at ∼512 and ∼724nm. The luminescence intensities vary between Sn filled and unfilled tube parts. Keeping in mind that ZnS and ZnSe nanotubes may also be synthesized using the similar technique, we propose that the present method is a universal synthetic route toward single-crystalline IIB-VI group semiconductor nanotubes.

Dissipation in quasi-one-dimensional superconducting single-crystalSnnanowires

Electrical transport measurements were made on single-crystal Sn nanowires to understand the intrinsic dissipation mechanisms of a one-dimensional superconductor. While the resistance of wires of diameter larger than 70 nm drops precipitately to zero at Tc near 3.7 K, a residual resistive tail extending down to low temperature is found for wires with diameters of 20 and 40 nm. As a function of temperature, the logarithm of the residual resistance appears as two linear sections, one within a few tenths of a degree below Tc and the other extending down to at least 0.47 K, the minimum temperature of the measurements. The residual resistance is found to be ohmic at all temperatures below Tc of Sn. These findings are suggestive of a thermally activated phase slip process near Tc and quantum fluctuation-induced phase slip process in the low temperature regime. When the excitation current exceeds a critical value, the voltage-current (V-I) curves show a series of discrete steps in approaching the normal state. These steps cannot be fully understood with the classical Skocpol-Beasley-Tinkham phase slip center model (PSC), but can be qualitatively accounted for partly by the PSC model modified by Michotte et al.

Template Assisted Fabrication of Tin Nanospheres by Thermal Expansion and Rapid Solidification Process

Tin (Sn) nanospheres with diameters ranging from 100 to 300 nm were fabricated by thermal expansion and rapid solidification process. The Sn melt was injected into an anodic aluminum oxide (AAO) template to form Sn nanowires. The Sn nanowire and AAO composite was then heated to the Sn melting temperature (∼232°C) and quenched to low temperature (8°C). The Sn melt exhibits high surface tension and AAO has nanoscale roughness on its surface. These two properties caused Sn nanospheres to form easily on the AAO surface when the partial Sn melt expanded out from AAO channels and rapidly solidified on the AAO surface.

Vapor−Solid Growth of Sn Nanowires: Growth Mechanism and Superconductivity

A noncatalytic and template-free vapor transport process has been employed to prepare single-crystalline Sn nanowires with diameters of 10-20 nm. The growth of one-dimensional Sn nanowires follows the mechanism similar to the vapor-solid (V-S) mechanism. Two-dimensional square-shaped nanostructures were also found to form in the region of lower deposition temperatures. The rich morphology may be attributed to the competition in growth rate among different crystallographic planes. Structural characterization with high-resolution transmission electron microscopy showed that the nanowires and nanosquares grew in a preferential direction of [200]. The superconducting transition temperatures for Sn nanowires and Sn nanosquares were about 3.7 K, which was very close to that of bulk beta-Sn. Magnetization measurements showed that the critical magnetic fields for both Sn nanowires and Sn nanosquares increased significantly as compared to that of bulk Sn.

Low temperature synthesized Sn doped indium oxide nanowires

Selective, well controlled and directionally grown Sn dopedIn2O3 nanowires(In2O3:Sn nanowires, SIO NWs) were synthesized at a low fabrication temperature () through a vapour–liquid–solid (VLS) process under a precise carrier gas flow. Themajority of the SIO NWs are grown along [222], with [400] and [440] as minority formingdirections, which implies a nearly epitaxial crystal structure. There are fewer physicaldefects, such as line or planar defects and contaminations, in the SIO NWs than in pureIn2O3 nanowires seen through high resolution transmission electron microscopy (HR-TEM)observations. The spectrum of photoluminescence (PL) emission indicates a stable strongblue light peak located at nm with an excited wavelength of 275 nm at room temperature. The Sn dopant in the SIO NWscan enhance the conductivity of the nanowires leading to the lowering of the turn-on electric-field to0.66 V µm−1 undera currentdensity of up to 1.0 mA cm−2 based on their field emission characteristics. Furthermore, the field emission enhancement coefficient,β, is alsoincreased to 1.48 × 105, which is very close to the carbon nanotube, (CNT) level. SIO NWs fabricated by a VLSprocess offer a potential application in flat panel displays as demonstrated in this study.

Development of phase-slip centers in superconducting Sn nanowires

By electrodeposition of tin inside the pores of a polycarbonate template, nanowires were grown, out of which a single one was contacted electrically so as to form a quasi-one-dimensional superconductor (diameter: 50nm). A resistive phase-slip center appears as a response to a pulse of supercritical current. Measuring its resistance, and its time of nucleation, gives access to the electron inelastic lifetime, and to the gap relaxation time, respectively, both in the nanosecond range. Finally, the threshold current for passage into the fully normal state indicates a good thermal contact with the polycarbonate matrix.

Synthesis and characterization of superconducting single-crystal Sn nanowires

Single-crystal superconducting tin nanowires with diameters of 40–160 nm have been prepared by electrochemical deposition in porous polycarbonate membranes. Structural characterization through transmission electron microscopy and x-ray diffraction showed that the nanowires are highly oriented along the [100] direction. Although the superconducting transition temperature is close to the bulk value of 3.7 K, the effect of reduced dimensionality is clearly evident in the electrical transport properties of the thinnest wires (40 nm diameter). Magnetization measurements show that the critical field of the nanowires increases significantly with decreasing diameter to ∼0.3 T for the thinnest wires, nearly an order of magnitude larger than the bulk value.

Current–voltage characteristics of Pb and Sn granular superconducting nanowires

Arrays of granular superconducting Pb and Sn nanowires (40–55 nm in diameter and 22 or 50 μm long) have been prepared by electrodeposition in nanoporous membranes. A simple technique has been developed to perform electrical transport measurement on a single nanowire. By sweeping the dc current inside the nanowire, we observed the formation of phase-slip-centers far below the critical temperature. In contrast, in voltage-driven experiments, an interesting S-shaped behavior has been observed in the nucleation region of these phase-slip-centers.

ChemInform Abstract: Selective Synthesis of Novel In and In3Sn Nanowires by an Organometallic Route at Room Temperature.

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Selective Synthesis of Novel In and In3Sn Nanowires by an Organometallic Route at Room Temperature

Simply decomposing InCp at room temperature in the presence of hexadecylamine leads to the formation of indium nanowires with a crystalline bct structure, a mean diameter of about 200 nm, and lengths in the micrometer range. The method can be extended to the preparation of In3 Sn nanowires of about 100 nm in diameter (a transmission electron micrograph is shown in the picture). Cp=C5 H5 (-) .

Selective synthesis of novel in and in3 sn nanowires by an organometallic route at room temperature.

Simply decomposing InCp at room temperature in the presence of hexadecylamine leads to the formation of indium nanowires with a crystalline bct structure, a mean diameter of about 200 nm, and lengths in the micrometer range. The method can be extended to the preparation of In3 Sn nanowires of about 100 nm in diameter (a transmission electron micrograph is shown in the picture). Cp=C5 H5 (-) .