Sb Nanowires Research Articles

Facile synthesis of micrometer-long antimony nanowires by template-free electrodeposition for next generation Li-ion batteries

High quality Sb nanowires of diameter < 50 nm can be electrodeposited from ionic liquid electrolytes containing GaCl3 and show promising Li-storage characteristics.

From Twinning to Pure Zincblende Catalyst-Free InAs(Sb) Nanowires.

III-V nanowires are candidate building blocks for next generation electronic and optoelectronic platforms. Low bandgap semiconductors such as InAs and InSb are interesting because of their high electron mobility. Fine control of the structure, morphology, and composition are key to the control of their physical properties. In this work, we present how to grow catalyst-free InAs1-xSbx nanowires, which are stacking fault and twin defect-free over several hundreds of nanometers. We evaluate the impact of their crystal phase purity by probing their electrical properties in a transistor-like configuration and by measuring the phonon-plasmon interaction by Raman spectroscopy. We also highlight the importance of high-quality dielectric coating for the reduction of hysteresis in the electrical characteristics of the nanowire transistors. High channel carrier mobilities and reduced hysteresis open the path for high-frequency devices fabricated using InAs1-xSbx nanowires.

Realization of Vertically Aligned, Ultrahigh Aspect Ratio InAsSb Nanowires on Graphite.

The monolithic integration of InAs(1-x)Sb(x) semiconductor nanowires on graphitic substrates holds enormous promise for cost-effective, high-performance, and flexible devices in optoelectronics and high-speed electronics. However, the growth of InAs(1-x)Sb(x) nanowires with high aspect ratio essential for device applications is extremely challenging due to Sb-induced suppression of axial growth and enhancement in radial growth. We report the realization of high quality, vertically aligned, nontapered and ultrahigh aspect ratio InAs(1-x)Sb(x) nanowires with Sb composition (xSb(%)) up to ∼12% grown by indium-droplet assisted molecular beam epitaxy on graphite substrate. Low temperature photoluminescence measurements show that the InAs(1-x)Sb(x) nanowires exhibit bright band-to-band related emission with a distinct redshift as a function of Sb composition providing further confirmation of successful Sb incorporation in as-grown nanowires. This study reveals that the graphite substrate is a more favorable platform for InAs(1-x)Sb(x) nanowires that could lead to hybrid heterostructures possessing potential device applications in optoelectronics.

Temperature and magnetic dependence of the resistance and thermopower in the topological insulator Bi1−xSbx nanowires

We report on the electrical transport and thermoelectric properties of Bi1−xSbx nanowires in the semiconductor region made of Bi1−xSbx. Such alloys are classified as topological insulators. The individual Bi–17 at%Sb wires in a glass capillary with diameters ranging from 100 to 1000 nm were prepared by high‐frequency liquid‐phase casting in an argon atmosphere. They were cylindrical single crystals with (1011) orientation along the wire axis. For large‐diameter wires we observed that the temperature‐dependent resistance, R(T), displays the temperature‐activated dependence that is expected of semiconductors. We also found that small‐diameter wires at low temperatures show a sharp deviation from the behavior of the resistance R(T), characteristic of semiconductors. The contrasting behavior of wires of different diameters can be interpreted in terms of the conductance of the surface states in BiSb where the surface states arise through a spin‐orbital Rashba interaction in the surface of BiSb. The thermopower remains negative over the entire temperature range, but it is strongly temperature dependent. The longitudinal magnetoresistance R(H) at low temperature shows quantum Shubnikov–de Haas oscillations only in thin (d < 200 nm) Bi–17 at%Sb nanowires. Only high‐mobility carriers display SdH oscillations. Since we expect the electronic transport in the 200‐nm semiconducting Bi1−xSbx nanowires to be dominated by the surface, this indicates that the surface states have sufficiently high mobility to display SdH.

Synthesis of metallic, semiconducting, and semi-metallic nanowires through control of InSb growth parameters

In this work we present a simple route to grow metallic, semiconducting or semi-metallic nanowires by chemical vapor deposition. Metallic indium (In), semiconducting indium antimonide (InSb) and semi-metallic antimony (Sb) nanowires were successfully synthesized by controlling temperature and hence Sb vapor pressure in the higher eutectic region of the InSb phase diagram. Semiconducting InSb nanowires were synthesized by direct antimonidization of In droplets at a temperature of 480 °C in an Sb-rich environment. I–V measurements on a single 50 nm thick InSb nanowire field-effect transistor show electrons to be the majority carriers with an electron concentration of ≈1018 cm−3. Thermally activated Arrhenius conduction was observed in the temperature range from 200–325 K, yielding an activation energy of 0.11 eV. Metallic In nanowires were grown at 600 °C, using a process similar to that for the growth of InSb nanowires. However, the higher growth temperature resulted in Sb re-evaporating from the growing nanowire crystal, leading to growth of In nanowires. The In nanowires were found to have an extremely high (≈1021 cm−3) electron concentration. Temperature dependent conductivity measurements show that at high temperatures the In nanowire conductivity varies as T−3/2, suggesting that acoustic phonons controlled electron transport. Antimony nanowire growth occurred at 400 °C by a self-catalyzed growth mechanism. Electron transport measurements on a single Sb nanowire reveal p-type conduction, with a hole concentration of ≈1019 cm−3. A higher hole mobility compared to electron mobility and the presence of surface states is the most likely cause of the hole-dominated conductivity in the Sb nanowires.

Thermoelectricity in semiconductor nanowires

Abstractmagnified imageIn this paper, we provide a comprehensive review on recent advances in the development of semiconductor nanowires for thermoelectric energy conversion. Semiconductor nanowires can exhibit novel properties in the electron and phonon transport as their diameters approach the characteristic length scales of the material such as the electron wavelength and the phonon mean free path. These size effects in semiconducting nanowires are discussed as a means to enhance the thermoelectric properties of the nanowires over their bulk counterparts. Challenges for the enhancement are also identified. We present recent theoretical and experimental results on various thermoelectric nanowires including Si, Ge, InAs, Bi, Bi–Te and Bi–Sb nanowires. Various characterization techniques for the accurate electrical and thermal measurements of individual nanowires are also covered. Finally, we mention briefly the recent efforts to fabricate thermoelectric devices using nanowire arrays. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

High-performance nonvolatile Al/AlOx/CdTe:Sb nanowire memory device

Here we demonstrate a room temperature processed nonvolatile memory device based on an Al/AlOx/CdTe:Sb nanowire (NW) heterojunction. Electrical analysis shows an echelon hysteresis composed of a high-resistance state (HRS) and a low-resistance state (LRS), which can allow it to write and erase data from the device. The conductance ratio is as high as 106, with a retention time of 3 × 104 s. Moreover, the SET voltages ranged from +6 to +8 V, whilst the RESET voltage ∼0 V. In addition, flexible memory nano-devices on PET substrate with comparable switching performance at bending condition were fabricated. XPS analysis of the Al/AlOx/CdTe:Sb NW heterojunction after controlled Ar+ bombardment reveals that this memory behavior is associated with the presence of ultra-thin AlOx film. This Al/AlOx/CdTe:Sb NW heterojunction will open up opportunities for new memory devices with different configurations.

First-principles study of structural and electronic properties of gallium based nanowires

Structural stability and electronic properties of GaX (X = N, P, As and Sb) nanowires have been investigated using first-principles based density function theory approach. Out of linear, zigzag, square and hexagon shaped configuration, the square shaped geometry is energetically most stable. The computation of lattice parameters, bulk modulus and pressure derivatives for these Ga based nanowires observes the highest bulk modulus for hexagonal shaped GaN nanowire amongst all, suggest the mechanical strength of this geometry. Electronic band structures analysis shows the semiconducting as well as metallic behavior of these nanowires.

Diameter-Dependent Photocurrent in InAsSb Nanowire Infrared Photodetectors

Photoconductors using vertical arrays of InAs/InAs(1-x)Sb(x) nanowires with varying Sb composition x have been fabricated and characterized. The spectrally resolved photocurrents are strongly diameter dependent with peaks, which are red-shifted with diameter, appearing for thicker wires. Results from numerical simulations are in good agreement with the experimental data and reveal that the peaks are due to resonant modes that enhance the coupling of light into the wires. Through proper selection of wire diameter, the absorptance can be increased by more than 1 order of magnitude at a specific wavelength compared to a thin planar film with the same amount of material. A maximum 20% cutoff wavelength of 5.7 μm is obtained at 5 K for a wire diameter of 717 nm at a Sb content of x = 0.62, but simulations predict that detection at longer wavelengths can be achieved by increasing the diameter. Furthermore, photodetection in InAsSb nanowire arrays integrated on Si substrates is also demonstrated.

Fabrication of p-type ZnSe:Sb nanowires for high-performance ultraviolet light photodetector application

p-type ZnSe nanowires (NWs) with tunable electrical conductivity were fabricated on a large scale by evaporating a mixed powder composed of ZnSe and Sb in different ratios. According to the structural characterization, the Sb-doped ZnSe NWs are of single crystalline form and grow along the [001] direction. The presence of Sb in the ZnSe NWs was confirmed by XPS spectra. Electrical measurement of a single ZnSe:Sb NW based back-gate metal–oxide field-effect-transistor reveals that all the doped NWs exhibit typical p-type conduction characteristics, and the conductivity can be tuned over eight orders of magnitude, from 6.36 × 10−7 S cm−1 for the undoped sample to ∼37.33 S cm−1 for the heavily doped sample. A crossed p–n nano-heterojunction photodetector made from the as-doped nanostructures displays pronounced rectification behavior, with a rectification ratio as high as 103 at ±5 V. Remarkably, it exhibits high sensitivity to ultraviolet light illumination with good reproducibility and quick photoresponse. Finally, the work mechanism of such a p–n junction based photodetector was elucidated. The generality of the above result suggests that the as-doped p-type ZnSe NWs will find wide application in future optoelectronics devices.

High-Current GaSb/InAs(Sb) Nanowire Tunnel Field-Effect Transistors

We present electrical characterization of GaSb/InAs(Sb) nanowire tunnel field-effect transistors. The broken band alignment of the GaSb/InAs(Sb) heterostructure is exploited to allow for interband tunneling without a barrier, leading to high on-current levels. We report a maximum drive current of 310 μA/μm at VDS = 0.5 V. Devices with scaled gate oxides display transconductances up to gm = 250 mS/mm at VDS = 300 mV, which are normalized to the nanowire circumference at the axial heterojunction.

Abnormal Photoelectric and Magnetic Properties of Three-Dimensional Super-Structure Sb Nanocages and One-Dimensional Nanowires

Three-dimensional (3D) super-structure Sb nanocages and One-dimensional (1D) Sb nanowires were successfully synthesized via a facile electrochemical deposition method. The structures of the samples were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV-vis spectrophotometry. In addition, the photoelectric performances and the magnetic properties of the samples were investigated. It is disclosed that the nanostructured Sb could be a promising candidate for photovoltaic material. Magnetization measurement indicates that 3D super-structure Sb nanocages show paramagnetic behavior at room temperature and ferromagnetism at 5K.

Thermoelectric Phenomena in Bi<SUB>1–x</SUB>Sb<SUB><I>x</I></SUB> Nanowires in Semimetal and Gapless Region

The paper report results of magneto-thermoelectric properties the single crystal Bi1-xSbx nanowires in glass cover with different diameters prepared by Ulitovsky-Taylor method. We study the effect of nanowire dimensionality in the Bi1-xSbx, nanowires in semimetal and gapless states. In the semimetal region Bi1-xSbx nanowires (x = 0.02) the semimetal-semiconductor transition due to quantum size effect at the critical diameter significantly higher than for pure Bi-wire are observed. This allowed to separate the effects related to the size quantization and surface state. It is shown that a weak magnetic fields leads to an increase of the hole contribution to the thermopower and to increase the Power factor alpha(2)sigma at positive alpha in Bi-2 at% Sb nanowires. Bi1-xSbx wires in gapless region (x = 0.06) shows the increase of the energy gap with decreasing the diameter d and increase of the electron contribution to the thermopower alpha in weak transverse magnetic field at the negative alpha. This will use the investigated wires as n- and p-branches in thermoelectric energy converters. Power factor depending on diameter B1-xSbx nanowires, composition, temperature, magnetic field is calculated.

Focused ion beam induced synthesis of antimony nanowires for gas sensor applications

In this paper the formation of antimony (Sb) nanowires (NWs) by a focused Ga ion beam approach and their gas sensing capability is reported. The NWs with uniform diameters of only 25 nm and lengths up to several microns are synthesized at predefined positions at room temperature in an ion beam induced self-assembling process. Then individual Sb-NWs are deposited on insulating substrates and provided with gold electrodes. Subsequently sensing characteristics of individual Sb-NWs are investigated at room temperature for H2O, CO, H2, He, O2 and ethanol over a wide concentration range. The Sb-NWs exhibit selective sensing properties for ethanol and H2O with exceptional sensitivities of more than 17 000 and 60 000, respectively.

Structural and electronic properties of AlX (X = P, As, Sb) nanowires: Ab initio study

Present paper discusses the structural stability and electronic properties of AlX (X = P, As and Sb) nanowires in its linear, zigzag, ladder, square and hexagonal type atomic configurations. The structural optimization has been performed in self consistence manner by using generalized gradient approximation with revised Perdew, Burke and Ernzerhof type parameterization. The study observes that in all the three nanowires, the square shaped atomic configuration is the most stable one. The calculated electronic band structures and density of states profile confirms the semiconducting behaviour of linear and zigzag shaped nanowires of AlP, whereas for AlAs and AlSb nanowires are metallic. The ground state properties have also been analysed in terms of bond length, bulk modulus and pressure derivative for all the nanowires along with their bulk counterpart. The lower bulk modulus of all the linear shaped geometries of AlX nanowires in comparison to its bulk counterpart indicates softening of the material at reduced dimension.

Demonstration of Defect-Free and Composition Tunable GaxIn1–xSb Nanowires

The Ga(x)In(1-x)Sb ternary system has many interesting material properties, such as high carrier mobilities and a tunable range of bandgaps in the infrared. Here we present the first report on the growth and compositional control of Ga(x)In(1-x)Sb material grown in the form of nanowires from Au seeded nanoparticles by metalorganic vapor phase epitaxy. The composition of the grown Ga(x)In(1-x)Sb nanowires is precisely controlled by tuning the growth parameters where x varies from 1 to ∼0.3. Interestingly, the growth rate of the Ga(x)In(1-x)Sb nanowires increases with diameter, which we model based on the Gibbs-Thomson effect. Nanowire morphology can be tuned from high to very low aspect ratios, with perfect zinc blende crystal structure regardless of composition. Finally, electrical characterization on nanowire material with a composition of Ga(0.6)In(0.4)Sb showed clear p-type behavior.

Influence of doping on the electronic transport in GaSb/InAs(Sb) nanowire tunnel devices

The effect of various doping profiles on the electronic transport in GaSb/InAs(Sb) nanowire tunnel diodes is investigated. Zn-doping of the GaSb segment increases both the peak current density and the current level in reverse bias. Top-gated diodes exhibit peak current modulation with a threshold voltage which can be controlled by Zn-doping the InAs(Sb) segment. By intentionally n-doping the InAs(Sb) segment degenerate doping on both sides of the heterojunction can be achieved, as well as tunnel diodes with peak current of 420 kA/cm2 at VDS = 0.16 V and a record-high current density of 3.6 MA/cm2 at VDS = −0.5 V.

Anisotropic interface induced formation of Sb nanowires on GaSb(111)A substrates

The growth of Sb nanowires on GaSb(111)A substrates is studied by in situ azimuthal scan reflection high-energy electron diffraction (ARHEED). Bulk and layer contributions can be distinguished in the ARHEED transmission pattern through the Sb nanowires. The three-dimensional structure of the growing Sb nanowires is identified by post-growth atomic force microscopy (AFM) and x-ray diffraction (XRD). The lattice match of the Sb crystal along the and the GaSb crystal along directions lead to a preferential orientation of the Sb nanowires. The Sb adsorption and desorption kinetics is studied by thermal desorption spectroscopy.

Prospects of nanostructures Bi1−xSbx for thermoelectricity

It has been predicted that surface states of topological insulators have large a thermopower and also ultrahigh mobilities. The authors report results of a magneto-thermoelectric investigation of single crystal Bi1−xSbx nanowires in a glass cover with diameters ranging from 90nm to 5μm. The wide-ranging antimony concentration enabled us to study the effect of nanowire dimensionality in the semimetal, semi-conductor and gapless regimes. Quantum size effects in Bi-2at%Sb nanowires, which are shown in temperature dependences of resistance R(T) and thermopower α(T) for the diameters significantly higher than the critical diameter for pure Bi-wires, are observed. The thermopower in weak magnetic fields, reaches values +400μV/K at Т=20–40K. Power factor α2σ depending on diameter of wires, structure, temperature and magnetic field is calculated. In connection with topological insulators, we will discuss the surface effect in the thermoelectric properties that we observe.

Formation of the Axial Heterojunction in GaSb/InAs(Sb) Nanowires with High Crystal Quality

Switching of the group-III element in III–V nanowire heterostructures is difficult due to the high solubility of group-III atoms in the Au seed particle. In addition, switching from Sb to a different group-V element has not been achieved in binary materials, largely due to its high solubility in Au. In metal–organic vapor phase epitaxy (MOVPE) growth, the use of Sb precursors presents further complications due to reactor background contamination. In this paper, we demonstrate growth of GaSb/InAs(Sb) nanowire heterostructures with potential applications in tunneling devices and study the processes occurring during the transition from GaSb to InAs growth. We show how the heterostructure can be grown with a sharp transition by taking advantage of a growth stop, which occurs naturally as the Au seed particle is emptied of Ga and filled with In. The remaining Sb background in the reactor during the InAs growth results in a finite Sb incorporation into this segment. This has the advantage of suppressing stackin...