EFFECT OF ELECTRIC FIELD, TEMPERATURE AND CORE DIMENSIONS IN III–V COMPOUND CORE–SHELL NANOWIRES

NANO ◽  
2014 ◽  
Vol 09 (04) ◽  
pp. 1450051
Author(s):  
ASHWANI VERMA ◽  
BAHNIMAN GHOSH ◽  
AKSHAY KUMAR SALIMATH
Keyword(s):  
Monte Carlo ◽  
Electric Field ◽  
Spin Relaxation ◽  
Compound Semiconductor ◽  
Core Shell ◽  
Relaxation Length ◽  
The Core ◽  
Field Temperature ◽  
Simulation Results ◽  
Shell Nanowires

In this paper, we have used semiclassical Monte Carlo method to show the dependence of spin relaxation length in III–V compound semiconductor core–shell nanowires on different parameters such as lateral electric field, temperature and core dimensions. We have reported the simulation results for electric field in the range of 0.5–10 kV/cm, temperature in the range of 77–300 K and core length ranging from 2 nm to 8 nm. The spin relaxation mechanisms used in III–V compound semiconductor core–shell nanowire are D'yakonov–Perel (DP) relaxation and Elliott–Yafet (EY) relaxation. Depending upon the choice of materials for core and shell, nanowire forms two types of band structures. We have used InSb – GaSb core–shell nanowire and InSb – GaAs core–shell nanowire and nanowire formed by swapping the core and shell materials to show all the results.

Regulating the electronic and optical properties of GaN/InN core/shell nanowires: A first-principles study

2020 ◽  
Vol 34 (25) ◽  
pp. 2050214 ◽  
Author(s):  
Chang Liu ◽  
Enling Li ◽  
Tuo Peng ◽  
Kaifei Bai ◽  
Yanpeng Zheng ◽  
...  
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Core Shell ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
Gan Nanowires ◽  
The Core ◽  
Light Region ◽  
Calculation Results ◽  
Shell Nanowires

In this paper, electronic and optical properties of GaN/InN core/shell nanowires (CSNWs) have been theoretically investigated through the first principles calculations. The binding energy of In and N atoms on surface of six crystal planes along the [Formula: see text]-axis of GaN nanowires are all negative, which indicate that In and N atoms can be effectively deposited on the surface of GaN nanowires and preparing GaN/InN CSNWs is feasible theoretically. Calculation results of electronic properties indicate that the core/shell ratio and diameter of GaN/InN CSNWs have significant effect on the band structure, bandgap can be effectively adjusted when keeping the number of GaN layers unchanged and changing the number of InN layers. Moreover, with the increase in the number of InN layers, the absorption spectrum of GaN/InN CSNW has significant redshift and few weak absorption peaks appear in the visible light region.

scholarly journals MONTE CARLO SIMULATION OF SPIN RELAXATION IN NANOWIRES AND 2-D CHANNELS OF II–VI SEMICONDUCTORS

SPIN ◽  
2012 ◽  
Vol 02 (02) ◽  
pp. 1250007 ◽  
Author(s):  
ASHUTOSH SHARMA ◽  
SWETALI NIMJE ◽  
AKSHAYKUMAR SALIMATH ◽  
BAHNIMAN GHOSH
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
External Field ◽  
Spin Relaxation ◽  
Simulation Method ◽  
Relaxation Length ◽  
Factors Affecting ◽  
Spin Dephasing ◽  
Spin Polarized ◽  
The Many

We have analyzed spin relaxation behavior of various II–VI semiconductors for nanowire structure and 2-D channel by simulating spin polarized transport through a semiclassical approach. Monte Carlo simulation method has been applied to simulate our model. D'yakonov–Perel mechanism and Elliot–Yafet mechanism are dominant for spin relaxation in II–VI semiconductors. Variation in spin relaxation length with external field has been analyzed and comparison is drawn between nanowire and 2-D channels. Spin relaxation lengths of various II–VI semiconductors are compared at an external field of 1 kV/cm to understand the predominant factors affecting spin dephasing in them. Among the many results obtained, most noticeable one is that spin relaxation length in nanowires is many times greater than that in 2-D channel.

Ferromagnetic ZnO-TiO2 Core-Shell Nanowire PhotoCatalyst with High Efficiency and Recyclability

2011 ◽  
Vol 90-93 ◽  
pp. 1702-1705
Author(s):  
Xi Zhang ◽  
Gang Xiang
Keyword(s):  
High Efficiency ◽  
Hole Concentration ◽  
Band Gaps ◽  
The Other ◽  
Band Edge ◽  
Core Shell ◽  
Hole Density ◽  
The Core ◽  
Recyclable Photocatalyst ◽  
Shell Nanowires

We demonstrate the design of the recyclable photocatalyst based on ferromagnetic (FM) ZnO- TiO2 core-shell nanowires (NWs). Since the band gaps and band edge energies of bulk ZnO and anatase TiO2 are equal to each other within about 45mV, TiO2 and ZnO can form an p-p+ heterojunction free of band discontinuities and with a built-in potential. The resulting radial field will increase hole density in the TiO2 layer while reduce hole concentration at the interface between the core and the shell, which in turn will decrease the rate of recombination in the photocatalytic TiO2, and hence increase the efficiency of photocatalyst. On the other hand, the NWs with FM cores can be easily collected and refreshed using solenoid and suitable for the recyclable usage of the NW catalyst

scholarly journals Spin Relaxation in Germanium Nanowires

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
Ashish Kumar ◽  
M. W. Akram ◽  
Bahniman Ghosh
Keyword(s):  
Electric Field ◽  
Spin Relaxation ◽  
Spin Density Matrix ◽  
Relaxation Length ◽  
Germanium Nanowires ◽  
Spin Dephasing ◽  
Electric Field Dependence ◽  
Spin Polarized ◽  
Structural Inversion ◽  
Inversion Asymmetry

We use semiclassical Monte Carlo approach along with spin density matrix calculations to model spin polarized electron transport. The model is applied to germanium nanowires and germanium two-dimensional channels to study and compare spin relaxation between them. Spin dephasing in germanium occurs because of Rashba Spin Orbit Interaction (structural inversion asymmetry) which gives rise to the D’yakonov-Perel (DP) relaxation. In germanium spin flip scattering due to the Elliot-Yafet (EY) mechanism also leads to spin relaxation. The spin relaxation tests for both 1D and 2D channels are carried out at different values of temperature and driving electric field, and the variation in spin relaxation length is recorded. Spin relaxation length in a nanowire is found to be much higher than that in a 2D channel due to suppression of DP relaxation in a nanowire. At lower temperatures the spin relaxation length increases. This suggests that spin relaxation in germanium occurs slowly in a 1D channel (nanowires) and at lower temperatures. The electric field dependence of spin relaxation length was found to be very weak.

scholarly journals Design and fabrication of 125I seeds for brachytherapy using capillary-based microfluidic technique

Nukleonika ◽  
2021 ◽  
Vol 66 (2) ◽  
pp. 55-60
Author(s):  
Yuan Wang ◽  
Miao Zhang ◽  
Tong Song ◽  
Zhenqi Chang
Keyword(s):  
Monte Carlo ◽  
Dose Distribution ◽  
Core Shell ◽  
Core Size ◽  
The Core ◽  
125I Seeds ◽  
Transport Code ◽  
Core Shell Structure ◽  
Brachytherapy Source ◽  
Microfluidic Technique

Abstract A new kind of 125I seeds with a core-shell structure were synthesized by an easy assembling–disassembling coaxial capillaries microfluidic device. The dose distribution of a 125I brachytherapy source fabricated by arranging six 125I seeds collinearly within a cylindrical titanium capsule was simulated by modelling the source in a water phantom using Monte Carlo N-Particle Transport code. The influence of the motion and the core size of the 125I seeds on the dose distribution was also studied in this work.

scholarly journals Asymptotic analysis for the electric field concentration with geometry of the core-shell structure

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Zhiwen Zhao
Keyword(s):  
Electric Field ◽  
Blow Up ◽  
Core Shell ◽  
Singular Behavior ◽  
Practical Application ◽  
Function Type ◽  
The Core ◽  
The Matrix ◽  
Perfect Conductivity

<p style='text-indent:20px;'>In the perfect conductivity problem arising from composites, the electric field may become arbitrarily large as <inline-formula><tex-math id="M1">\begin{document}$ \varepsilon $\end{document}</tex-math></inline-formula>, the distance between the inclusions and the matrix boundary, tends to zero. In this paper, by making clear the singular role of the blow-up factor <inline-formula><tex-math id="M2">\begin{document}$ Q[\varphi] $\end{document}</tex-math></inline-formula> introduced in [<xref ref-type="bibr" rid="b27">27</xref>] for some special boundary data of even function type with <inline-formula><tex-math id="M3">\begin{document}$ k $\end{document}</tex-math></inline-formula>-order growth, we prove the optimality of the blow-up rate in the presence of <inline-formula><tex-math id="M4">\begin{document}$ m $\end{document}</tex-math></inline-formula>-convex inclusions close to touching the matrix boundary in all dimensions. Finally, we give closer analysis in terms of the singular behavior of the concentrated field for eccentric and concentric core-shell geometries with circular and spherical boundaries from the practical application angle.</p>

Magnetic Properties of the Cylindrical Ising Nanowire: A Monte Carlo Simulation Study

SPIN ◽  
2017 ◽  
Vol 07 (04) ◽  
pp. 1750011 ◽  
Author(s):  
A. Jabar ◽  
R. Masrour ◽  
M. Hamedoun ◽  
A. Benyoussef
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Magnetic Properties ◽  
Crystal Field ◽  
Remanent Magnetization ◽  
Hysteresis Loops ◽  
Core Shell ◽  
Monte Carlo Simulation Study ◽  
The Core ◽  
Magnetic Nanowire

A cylindrical ferrimagnetic magnetic nanowire system of core and shell layers has been investigated using Monte Carlo simulation. Critical temperature is obtained for different values of exchange couplings at the core–shell interface, at shell–shell and core–core. The total magnetization has been the determinate for different values of crystal field. Hysteresis loop, coercive field and remanent magnetization of a core and shell layers are obtained using the Monte Carlo simulation. A number of characteristic behaviors are found, such as the occurrence of single and triple hysteresis loops for appropriate values of crystal field, temperatures values and exchange interaction values.

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