Fabrication, Characterization and Electronic Properties of Bismuth Nanowire Systems

1998 ◽  
Vol 545 ◽  
Author(s):  
Zhibo B. Zhang ◽  
M. S. Dresselhaus ◽  
Jackie Y. Ying
Keyword(s):  
Aspect Ratio ◽  
Electrical Transport ◽  
Nanowire Array ◽  
Anodic Alumina ◽  
Electrical Transport Properties ◽  
Free Standing ◽  
Electron Effective Mass ◽  
Quantum Confinement Effects ◽  
Bi Nanowire ◽  
Low Dimensional

AbstractWe have fabricated ultra-fine Bi nanowire (10–120 nm) arrays with packing densities as high as 7.1 × 1010/cm2 by pressure injecting its liquid melt into the evacuated nano-channels of an anodic alumina template. Using this fabrication technique, we have also prepared Te-doped n-type Bi nanowires. Free-standing Bi nanowires with an aspect ratio (length/diameter) higher than 500 are obtained by etching away the anodic alumina matrix without attacking the Bi. The resulting Bi nanowires are shown to be single crystals (with the same crystal structure as bulk Bi) and all the wires of a nanowire array are similarly oriented along the wire axis. The small electron effective mass of Bi, the high anisotropy of its Fermi surface, and the large aspect ratio of the Bi nanowires make this a very promising material for low-dimensional thermoelectric applications and an excellent system for studying quantum confinement effects in a quasi-one-dimensional (1D) electron gas. A theoretical model based on the basic band structure of bulk Bi, suitably modified for the 1D situation, is constructed to explore the electrical transport properties of Bi nanowires, which are expected to be very different from those of bulk Bi.

Electrical Transport Properties of the Pentatelluride Materials Hfte5 and Zrte5

1997 ◽  
Vol 478 ◽  
Author(s):  
T. M. Tritt ◽  
M. L. Wilson ◽  
R. L. Littleton ◽  
C. Feger ◽  
J. Kolis ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Electrical Transport ◽  
Entire Range ◽  
Room Temperature ◽  
Polycrystalline Material ◽  
Polycrystalline Materials ◽  
Electrical Transport Properties ◽  
Low Dimensional ◽  
P Type

AbstractWe have measured the resistivity and thermopower of single crystals as well as polycrystalline pressed powders of the low-dimensional pentatelluride materials: HfTe5 and ZrTe5. We have performed these measurements as a function of temperature between 5K and 320K. In the single crystals there is a peak in the resistivity for both materials at a peak temperature, Tp where Tp ≈ 80K for HfTe5 and Tp ≈ 145K for ZrTe5. Both materials exhibit a large p-type thermopower around room temperature which undergoes a change to n-type below the peak. This data is similar to behavior observed previously in these materials. We have also synthesized pressed powders of polycrystalline pentatelluride materials, HfTe5 and ZrTe5. We have measured the resistivity and thermopower of these polycrystalline materials as a function of temperature between 5K and 320K. For the polycrystalline material, the room temperature thermopower for each of these materials is relatively high, +95 μV/K and +65 μV/K for HfTe5 and ZrTe5 respectively. These values compare closely to thermopower values for single crystals of these materials. At 77 K, the thermopower is +55 μV/K for HfTe5 and +35 μV/K for ZrTe5. In fact, the thermopower for the polycrystals decreases monotonically with temperature to T ≈ 5K, thus exhibiting p-type behavior over the entire range of temperature. As expected, the resistivity for the polycrystals is higher than the single crystal material, with values of 430 mΩ-cm and 24 mΩ-cm for Hfre5 and ZrTe5 respectively, compared to single crystal values of 0.35 mΩ-cm (HfTe5) and 1.0 mΩ-cm (ZrTe5). We have found that the peak in the resistivity evident in both single crystal materials is absent in these polycrystalline materials. We will discuss these materials in relation to their potential as candidates for thermoelectric applications.

Electrical Transport in Mesoporous Silicon Layers

1994 ◽  
Vol 358 ◽  
Author(s):  
M. Ben-Chorin ◽  
S. Grebner ◽  
F. Wang ◽  
R. Schwarz ◽  
A. Nikolov ◽  
...  
Keyword(s):  
Electrical Transport ◽  
Surface States ◽  
Dark Conductivity ◽  
Free Standing ◽  
Electron Conduction ◽  
Mesoporous Silicon ◽  
Methanol Vapor ◽  
Quantum Confinement Effects ◽  
P Type

ABSTRACTIn order to clarify the role of the enlarged surface area of porous silicon on the electrical conductivity, we have studied the transport in mesoporous silicon layers, for which quantum confinement effects are negligible. We prepare free standing mesoporous films, from highly doped p-type Si wafers. The dark conductivity of the mesoporous layers is activated with an energy of 0.5 eV. Thermopower measurements show negative sign indicating electron conduction. The exposure of these layers to methanol vapor results in an increased conductivity and change of the thermopower magnitude. Photoconductivity measurements and the Steady-State Photocarrier Grating technique (SSPG) are used to evaluate the density of the surface states and the dynamics of the photo-excited carriers. All these results indicate that a large density of surface states exist, which results in a depletion of the free holes.

scholarly journals Vertically Aligned n-Type Silicon Nanowire Array as a Free-Standing Anode for Lithium-Ion Batteries

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3137
Author(s):  
Andika Pandu Nugroho ◽  
Naufal Hanif Hawari ◽  
Bagas Prakoso ◽  
Andam Deatama Refino ◽  
Nursidik Yulianto ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Silicon Wafer ◽  
Silicon Nanowire ◽  
Nanowire Array ◽  
Lithium Ion ◽  
Free Standing ◽  
Silicon Anodes ◽  
Type Silicon ◽  
Silicon Nanowire Array ◽  
Vertically Aligned

Due to its high theoretical specific capacity, a silicon anode is one of the candidates for realizing high energy density lithium-ion batteries (LIBs). However, problems related to bulk silicon (e.g., low intrinsic conductivity and massive volume expansion) limit the performance of silicon anodes. In this work, to improve the performance of silicon anodes, a vertically aligned n-type silicon nanowire array (n-SiNW) was fabricated using a well-controlled, top-down nano-machining technique by combining photolithography and inductively coupled plasma reactive ion etching (ICP-RIE) at a cryogenic temperature. The array of nanowires ~1 µm in diameter and with the aspect ratio of ~10 was successfully prepared from commercial n-type silicon wafer. The half-cell LIB with free-standing n-SiNW electrode exhibited an initial Coulombic efficiency of 91.1%, which was higher than the battery with a blank n-silicon wafer electrode (i.e., 67.5%). Upon 100 cycles of stability testing at 0.06 mA cm−2, the battery with the n-SiNW electrode retained 85.9% of its 0.50 mAh cm−2 capacity after the pre-lithiation step, whereas its counterpart, the blank n-silicon wafer electrode, only maintained 61.4% of 0.21 mAh cm−2 capacity. Furthermore, 76.7% capacity retention can be obtained at a current density of 0.2 mA cm−2, showing the potential of n-SiNW anodes for high current density applications. This work presents an alternative method for facile, high precision, and high throughput patterning on a wafer-scale to obtain a high aspect ratio n-SiNW, and its application in LIBs.

scholarly journals Size-Dependent Electrical Transport Properties in Conducting Diamond Nanostripes

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1765
Author(s):  
Andrew F. Zhou ◽  
Elluz Pacheco ◽  
Badi Zhou ◽  
Peter X. Feng
Keyword(s):  
Transport Properties ◽  
Electrical Transport ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Electrical Transport Properties ◽  
Free Standing ◽  
Size Dependent ◽  
Ultrananocrystalline Diamond ◽  
Electron Transport Properties

With the advances in nanofabrication technology, horizontally aligned and well-defined nitrogen-doped ultrananocrystalline diamond nanostripes can be fabricated with widths in the order of tens of nanometers. The study of the size-dependent electron transport properties of these nanostructures is crucial to novel electronic and electrochemical applications. In this paper, 100 nm thick n-type ultrananocrystalline diamond thin films were synthesized by microwave plasma-enhanced chemical vapor deposition method with 5% N2 gas in the plasma during the growth process. Then the nanostripes were fabricated using standard electron beam lithography and reactive ion etching techniques. The electrical transport properties of the free-standing single nanostripes of different widths from 75 to 150 nm and lengths from 1 to 128 μm were investigated. The study showed that the electrical resistivity of the n-type ultrananocrystalline diamond nanostripes increased dramatically with the decrease in the nanostripe width. The nanostripe resistivity was nearly doubted when the width was reduced from 150 nm to 75 nm. The size-dependent variability in conductivity could originate from the imposed diffusive scattering of the nanostripe surfaces which had a further compounding effect to reinforce the grain boundary scattering.

scholarly journals Effects of Size Reduction on the Electrical Transport Properties of 3D Bi Nanowire Networks

2021 ◽  
pp. 2001069
Author(s):  
Michael Florian Peter Wagner ◽  
Anna Sarina Paulus ◽  
Joachim Brötz ◽  
Wilfried Sigle ◽  
Christina Trautmann ◽  
...  
Keyword(s):  
Transport Properties ◽  
Electrical Transport ◽  
Size Reduction ◽  
Electrical Transport Properties ◽  
Bi Nanowire ◽  
Nanowire Networks
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