scholarly journals Simulation of Quantum-Dot Structures in Si/SiO2

VLSI Design ◽  
1998 ◽  
Vol 6 (1-4) ◽  
pp. 335-339 ◽  
Author(s):  
Minhan Chen ◽  
Wolfgang Porod
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Boundary Conditions ◽  
Numerical Simulations ◽  
Material System ◽  
Exposed Surface ◽  
Confining Potential ◽  
The Poisson Equation ◽  
Charge Model ◽  
Electron Quantum

We present numerical simulations for the design of gated few-electron quantum dot structures in the Si/SiO2 material system. Because of the vicinity of the quantum dots to the exposed surface, we take special care in treating the boundary conditions at the oxide/vacuum interfaces. In our simulations, the confining potential is obtained from the Poisson equation with a Thomas-Fermi charge model. We find that the dot occupancy can be effectively controlled in the few-electron regime.

scholarly journals Electrostatic Formation of Coupled Si/SiO2 Quantum Dot Systems

VLSI Design ◽  
1998 ◽  
Vol 8 (1-4) ◽  
pp. 555-558 ◽  
Author(s):  
Per Hyldgaard ◽  
Henry K. Harbury ◽  
Wolfgang Porod
Keyword(s):  
Quantum Dot ◽  
Three Dimensional ◽  
Effective Control ◽  
Insulating Layer ◽  
Charge Densities ◽  
The Poisson Equation ◽  
Charge Model ◽  
Dimensional Finite Element ◽  
Electron Quantum ◽  
Three Dimensional Finite Element

We present three-dimensional numerical modeling results for gated Si/SiO2 quantum dot systems in the few-electron regime. In our simulations, the electrostatic confining potential results from the Poisson equation assuming a self-consistent Thomas-Fermi charge model. We find that a very thin SiO2 top insulating layer allows an effective control with single-electron confinement in quantum dots with radius less than 10nm and investigate the detailed potential and resulting charge densities. Our three-dimensional finite-element modeling tool allows future investigations of the charge coupling in gated few-electron quantum-dot cellular automata.

ENTANGLEMENT IN TWO VERTICALLY COUPLED IDENTICAL SINGLE-ELECTRON QUANTUM DOTS

2002 ◽  
Vol 16 (23n24) ◽  
pp. 907-913 ◽  
Author(s):  
ZHAN-JUN ZHANG ◽  
HAO-XUE QIAO ◽  
BAI-WEN LI
Keyword(s):  
Magnetic Field ◽  
Quantum Dots ◽  
External Magnetic Field ◽  
Quantum Dot ◽  
Single Electron ◽  
Von Neumann ◽  
Electron Quantum

The evolutions of the von Neumann entropies of the low-lying states in two vertically coupled identical single-electron quantum dot systems with increasing magnetic field and inter-dot separation have been investigated. We show that both the external magnetic field and the inter-dot separation can induce the transition of the entropy of the system. Additionally, a suspicion (that is, the higher the excitation, the larger entropy) has been clarified and proven to be incorrect.

InAs/GaAs single-electron quantum dot qubit

2001 ◽  
Vol 90 (12) ◽  
pp. 6151-6155 ◽  
Author(s):  
Shu-Shen Li ◽  
Jian-Bai Xia ◽  
Jin-Long Liu ◽  
Fu-Hua Yang ◽  
Zhi-Chuan Niu ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Single Electron ◽  
Electron Quantum

NiAg-graphene quantum dot-graphene hybrid with high oxidase-like catalytic activity for sensitive colorimetric detection of malathion

2021 ◽  
Author(s):  
Xu Dan ◽  
Ruiyi Li ◽  
Qinsheng Wang ◽  
Yongqiang Yang ◽  
Haiyan Zhu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Catalytic Activity ◽  
Quantum Dot ◽  
Colorimetric Detection ◽  
Graphene Quantum Dots ◽  
Functionalized Graphene ◽  
Graphene Quantum Dot ◽  
Nickel Silver

The paper reports the synthesis of nickel-silver-graphene quantum dot-graphene hybrid. Histidine-functionalized graphene quantum dots (His-GQDs) were bonded to graphene oxide (GO) and then combined with Ni2+ and Ag+ to form...

scholarly journals Effect of Growth Temperature on the Characteristics of CsPbI3-Quantum Dots Doped Perovskite Film

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4439
Author(s):  
Shui-Yang Lien ◽  
Yu-Hao Chen ◽  
Wen-Ray Chen ◽  
Chuan-Hsi Liu ◽  
Chien-Jung Huang
Keyword(s):  
Thin Films ◽  
Thermal Stability ◽  
Quantum Dots ◽  
Quantum Dot ◽  
Growth Temperature ◽  
Electron Mobility ◽  
Surface Defects ◽  
Different Temperatures ◽  
Pb Doping ◽  
Pristine Film

In this study, adding CsPbI3 quantum dots to organic perovskite methylamine lead triiodide (CH3NH3PbI3) to form a doped perovskite film filmed by different temperatures was found to effectively reduce the formation of unsaturated metal Pb. Doping a small amount of CsPbI3 quantum dots could enhance thermal stability and improve surface defects. The electron mobility of the doped film was 2.5 times higher than the pristine film. This was a major breakthrough for inorganic quantum dot doped organic perovskite thin films.

Carbon quantum dot-sensitized hollow TiO2 spheres for high-performance visible light photocatalysis

2021 ◽  
Author(s):  
Xianfeng Zhang ◽  
Zongqun Li ◽  
Shaowen Xu ◽  
Yaowen Ruan
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
High Performance ◽  
Carbon Quantum Dots ◽  
Visible Light Photocatalysis ◽  
Carbon Quantum Dot ◽  
Visible Light Photocatalytic

TiO2/CQD composites were synthesized through carbon quantum dots covalently attached to the surface of hollow TiO2 spheres for visible light photocatalytic degradation of organics.

scholarly journals Structural and compositional analysis of (InGa)(AsSb)/GaAs/GaP Stranski–Krastanov quantum dots

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Raja S. R. Gajjela ◽  
Arthur L. Hendriks ◽  
James O. Douglas ◽  
Elisa M. Sala ◽  
Petr Steindl ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Flash Memory ◽  
Compositional Analysis ◽  
Structural Data ◽  
Scanning Tunneling ◽  
Valuable Insight ◽  
Material System ◽  
Tunneling Microscopy ◽  
Cross Sectional ◽  
Fe Simulations

AbstractWe investigated metal-organic vapor phase epitaxy grown (InGa)(AsSb)/GaAs/GaP Stranski–Krastanov quantum dots (QDs) with potential applications in QD-Flash memories by cross-sectional scanning tunneling microscopy (X-STM) and atom probe tomography (APT). The combination of X-STM and APT is a very powerful approach to study semiconductor heterostructures with atomic resolution, which provides detailed structural and compositional information on the system. The rather small QDs are found to be of truncated pyramid shape with a very small top facet and occur in our sample with a very high density of ∼4 × 1011 cm−2. APT experiments revealed that the QDs are GaAs rich with smaller amounts of In and Sb. Finite element (FE) simulations are performed using structural data from X-STM to calculate the lattice constant and the outward relaxation of the cleaved surface. The composition of the QDs is estimated by combining the results from X-STM and the FE simulations, yielding ∼InxGa1 − xAs1 − ySby, where x = 0.25–0.30 and y = 0.10–0.15. Noticeably, the reported composition is in good agreement with the experimental results obtained by APT, previous optical, electrical, and theoretical analysis carried out on this material system. This confirms that the InGaSb and GaAs layers involved in the QD formation have strongly intermixed. A detailed analysis of the QD capping layer shows the segregation of Sb and In from the QD layer, where both APT and X-STM show that the Sb mainly resides outside the QDs proving that Sb has mainly acted as a surfactant during the dot formation. Our structural and compositional analysis provides a valuable insight into this novel QD system and a path for further growth optimization to improve the storage time of the QD-Flash memory devices.

scholarly journals Metalorganic chemical vapor deposition of InN quantum dots and nanostructures

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Caroline E. Reilly ◽  
Stacia Keller ◽  
Shuji Nakamura ◽  
Steven P. DenBaars
Keyword(s):  
Quantum Dots ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Near Infrared ◽  
Optoelectronic Devices ◽  
Chemical Vapor ◽  
Electromagnetic Spectrum ◽  
Material System ◽  
Metalorganic Chemical

AbstractUsing one material system from the near infrared into the ultraviolet is an attractive goal, and may be achieved with (In,Al,Ga)N. This III-N material system, famous for enabling blue and white solid-state lighting, has been pushing towards longer wavelengths in more recent years. With a bandgap of about 0.7 eV, InN can emit light in the near infrared, potentially overlapping with the part of the electromagnetic spectrum currently dominated by III-As and III-P technology. As has been the case in these other III–V material systems, nanostructures such as quantum dots and quantum dashes provide additional benefits towards optoelectronic devices. In the case of InN, these nanostructures have been in the development stage for some time, with more recent developments allowing for InN quantum dots and dashes to be incorporated into larger device structures. This review will detail the current state of metalorganic chemical vapor deposition of InN nanostructures, focusing on how precursor choices, crystallographic orientation, and other growth parameters affect the deposition. The optical properties of InN nanostructures will also be assessed, with an eye towards the fabrication of optoelectronic devices such as light-emitting diodes, laser diodes, and photodetectors.

scholarly journals Flexible and efficient perovskite quantum dot solar cells via hybrid interfacial architecture

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Long Hu ◽  
Qian Zhao ◽  
Shujuan Huang ◽  
Jianghui Zheng ◽  
Xinwei Guan ◽  
...  
Keyword(s):  
Thin Film ◽  
Quantum Dots ◽  
Solar Cells ◽  
Quantum Dot ◽  
High Performance ◽  
Mechanical Stability ◽  
Mechanical Adhesion ◽  
Perovskite Quantum Dots ◽  
Efficient Charge ◽  
Photovoltaic Technologies

AbstractAll-inorganic CsPbI3 perovskite quantum dots have received substantial research interest for photovoltaic applications because of higher efficiency compared to solar cells using other quantum dots materials and the various exciting properties that perovskites have to offer. These quantum dot devices also exhibit good mechanical stability amongst various thin-film photovoltaic technologies. We demonstrate higher mechanical endurance of quantum dot films compared to bulk thin film and highlight the importance of further research on high-performance and flexible optoelectronic devices using nanoscale grains as an advantage. Specifically, we develop a hybrid interfacial architecture consisting of CsPbI3 quantum dot/PCBM heterojunction, enabling an energy cascade for efficient charge transfer and mechanical adhesion. The champion CsPbI3 quantum dot solar cell has an efficiency of 15.1% (stabilized power output of 14.61%), which is among the highest report to date. Building on this strategy, we further demonstrate a highest efficiency of 12.3% in flexible quantum dot photovoltaics.

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