Theoretical Study on the Transport through a Quantum Dots Array with a Side Quantum Dot

2011 ◽  
Vol 340 ◽  
pp. 331-336
Author(s):  
Hai Tao Yin ◽  
Xiao Jie Liu ◽  
Wei Long Wan ◽  
Cheng Bao Yao ◽  
Li Na Bai ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Green Function ◽  
Energy Level ◽  
Quantum Dot ◽  
Quantum Interference ◽  
Theoretical Study ◽  
Equation Of Motion ◽  
Function Technique ◽  
Motion Method ◽  
Linear Conductance

We studied transport properties through a noninteracting quantum dots array with a side quantum dot employing the equation of motion method and Green function technique. The linear conductance has been calculated numerically. It is shown that an antiresonance always pinned at the energy level of side quantum dot. The conductance develops Fano line shape when the side quantum dot level is not aligned with that of the quantum dots in the array due to quantum interference through different channels.

scholarly journals Theoretical study of strain-dependent optical absorption in a doped self-assembled InAs/InGaAs/GaAs/AlGaAs quantum dot

2018 ◽  
Vol 9 ◽  
pp. 1075-1084
Author(s):  
Tarek A Ameen ◽  
Hesameddin Ilatikhameneh ◽  
Archana Tankasala ◽  
Yuling Hsueh ◽  
James Charles ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Absorption ◽  
Quantum Dot ◽  
Mole Fraction ◽  
Theoretical Study ◽  
Energy Gap ◽  
Optical Transition ◽  
Binding Model ◽  
Self Assembled ◽  
Absorption Wavelength

A detailed theoretical study of the optical absorption in doped self-assembled quantum dots is presented. A rigorous atomistic strain model as well as a sophisticated 20-band tight-binding model are used to ensure accurate prediction of the single particle states in these devices. We also show that for doped quantum dots, many-particle configuration interaction is also critical to accurately capture the optical transitions of the system. The sophisticated models presented in this work reproduce the experimental results for both undoped and doped quantum dot systems. The effects of alloy mole fraction of the strain controlling layer and quantum dot dimensions are discussed. Increasing the mole fraction of the strain controlling layer leads to a lower energy gap and a larger absorption wavelength. Surprisingly, the absorption wavelength is highly sensitive to the changes in the diameter, but almost insensitive to the changes in dot height. This behavior is explained by a detailed sensitivity analysis of different factors affecting the optical transition energy.

Electron transport through two one-dimensional multi-quantum dot arrays coupled to four leads

2018 ◽  
Vol 32 (27) ◽  
pp. 1850333 ◽  
Author(s):  
Zelong He ◽  
Kongfa Chen ◽  
Mengchun Lu ◽  
Qiang Li
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Green’S Function ◽  
Green's Function ◽  
Energy Levels ◽  
Transmission Probability ◽  
Function Technique ◽  
One Dimensional ◽  
Resonance Band ◽  
Dc Current

Employing the non-equilibrium Green’s function technique, we have obtained the formula for dc current of two one-dimensional multi-quantum dot arrays, which couple to each other via tunneling coupling between two quantum dots connected to four leads, respectively. The retarded Green’s function is a staircase type, terminating at the four leads. Furthermore, the four quantum dots case is demonstrated. The influence of inter-dot coupling strength and quantum dot energy level on the transmission probability for TL, TM and TN branches is investigated. A non-resonant band is observed. By adjusting energy levels of quantum dots, a resonance emerges in the region of the non-resonance band. The system can be used as a quantum switch.

Modulation of magnetotransport in asymmetrically coupled double quantum dot system

2016 ◽  
Vol 30 (22) ◽  
pp. 1650266 ◽  
Author(s):  
Yan-Hua Liao ◽  
Jin Huang ◽  
Wei-Zhong Wang
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Quantum Dots ◽  
Energy Level ◽  
Quantum Dot ◽  
Spin Polarization ◽  
Quantum Phase Transition ◽  
Double Quantum ◽  
Double Quantum Dot ◽  
Double Quantum Dots

We study the transport properties in double quantum dots asymmetrically coupled to leads in magnetic field. We focus on the situation in which the second dot (QD2) couples with the leads with a weak hybridization function. The results shows that by tuning the energy level [Formula: see text] of QD2 one can control the conductance and its spin polarization of the system. In the absence of magnetic field [Formula: see text], with increasing [Formula: see text], the conductance shows a dip structure. This behavior of conductance results from a continuous triplet–doublet quantum phase transition. In the presence of magnetic field [Formula: see text], we obtain a perfect spin filtering with a fully-polarized conductance of up-spin or down-spin.

Spin thermoelectric transport in a four-quantum-dot ring: Influence of quantum dots magnetization

2018 ◽  
Vol 32 (33) ◽  
pp. 1850412 ◽  
Author(s):  
Feng Liang ◽  
Dong Zhang ◽  
Ben-Ling Gao ◽  
Yan-Zong Wang ◽  
Yu Gu
Keyword(s):  
Quantum Dots ◽  
Energy Level ◽  
Quantum Dot ◽  
Figure Of Merit ◽  
Spin Current ◽  
Pure Spin ◽  
Thermoelectric Effects ◽  
Thermoelectric Transport ◽  
Thermal Generator ◽  
Non Equilibrium Green’S Function

Non-equilibrium Green’s function method is applied to study the spin thermoelectric effects in a four-quantum-dot ring with two of the quantum dots magnetized. The influence of magnetic configuration on the spin thermoelectric transport through the system is investigated. In some magnetic configurations, a significant spin Seebeck coefficient [Formula: see text] can be generated with the variation of the quantum dot (QD) energy level. Appropriately tuning the QD energy level can let the present device work as a pure spin-up (spin-down) or a pure-spin-current thermal generator. The combined effect of the magnetization and magnetic flux (or Rashba spin-orbit coupling) is also investigated. Finally, the charge figure of merit [Formula: see text] and spin figure of merit [Formula: see text] are evaluated, it is found that the magnitude of the spin figure of merit can be comparable to that of the charge counterpart.

Boosting the photoelectric conversion efficiency of DSSCs through graphene quantum dots: Insights from theoretical study

2021 ◽  
Author(s):  
Yuanchao Li ◽  
Wenyuan Zhang ◽  
Xin Li ◽  
Yanling Xu
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Theoretical Study ◽  
Graphene Quantum Dots ◽  
Dye Sensitized Solar Cells ◽  
Photoelectric Conversion Efficiency ◽  
Photoelectric Conversion ◽  
Graphene Quantum Dot ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

The introduction of graphene quantum dot (GQD) into the photoactive layer of dye sensitized solar cells (DSSCs) has achieved encouraging results in the experiment. However, which one is the best...

Photoinduced conductivity enhancement in quantum dot/multilayer graphene nanostructures

2015 ◽  
Vol 1787 ◽  
pp. 15-19 ◽  
Author(s):  
Yulia A. Gromova ◽  
Ivan A. Reznik ◽  
Ilia A. Vovk ◽  
Simas Rackauskas ◽  
Andrei V. Alaferdov ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Quantum Dots ◽  
Energy Level ◽  
Quantum Dot ◽  
Level Structure ◽  
Hybrid Structures ◽  
Multilayer Graphene ◽  
Energy Level Structure ◽  
Conductivity Enhancement ◽  
Mild Conditions

ABSTRACTWe report on the formation of photoactive hybrid structures based on multilayer graphene nanobelts and CdSe/ZnS quantum dots (QDs) on Pt microelectrodes. We have found that heat treatment in mild conditions enhances rate of electrical photoresponse of the hybrid structures due to elimination of long-lived charge traps. We also show that the electrical photoresponse polarity depends on the energy level structure of the QDs.

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