scholarly journals Why one can expect large rectification in molecular junctions based on alkane monothiols and why rectification is so modest

2018 ◽  
Vol 9 (19) ◽  
pp. 4456-4467 ◽  
Author(s):  
Zuoti Xie ◽  
Ioan Bâldea ◽  
C. Daniel Frisbie
Keyword(s):  
High Performance ◽  
Stark Effect ◽  
Molecular Junctions ◽  
Alkane Thiols

The Stark effect plays a key role in understanding why, against expectation, alkane thiols are not high-performance molecular rectifiers.

scholarly journals Strain Investigation on Spin-Dependent Transport Properties of γ-Graphyne Nanoribbon Between Gold Electrodes

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yun Li ◽  
Xiaobo Li ◽  
Shidong Zhang ◽  
Liemao Cao ◽  
Fangping Ouyang ◽  
...  
Keyword(s):  
Transport Properties ◽  
High Performance ◽  
Density Functional ◽  
Strain Engineering ◽  
Molecular Junctions ◽  
Spin Splitting ◽  
Functional Theory ◽  
Spin Dependent Transport ◽  
The Density Functional Theory ◽  
Dependent Transport

AbstractStrain engineering has become one of the effective methods to tune the electronic structures of materials, which can be introduced into the molecular junction to induce some unique physical effects. The various γ-graphyne nanoribbons (γ-GYNRs) embedded between gold (Au) electrodes with strain controlling have been designed, involving the calculation of the spin-dependent transport properties by employing the density functional theory. Our calculated results exhibit that the presence of strain has a great effect on transport properties of molecular junctions, which can obviously enhance the coupling between the γ-GYNR and Au electrodes. We find that the current flowing through the strained nanojunction is larger than that of the unstrained one. What is more, the length and strained shape of the γ-GYNR serves as the important factors which affect the transport properties of molecular junctions. Simultaneously, the phenomenon of spin-splitting occurs after introducing strain into nanojunction, implying that strain engineering may be a new means to regulate the electron spin. Our work can provide theoretical basis for designing of high performance graphyne-based devices in the future.

scholarly journals Piezoelectric Level Splitting in GaInN/GaN Quantum Wells

1999 ◽  
Vol 4 (S1) ◽  
pp. 357-362
Author(s):  
C. Wetzel ◽  
T. Takeuchi ◽  
H. Amano ◽  
I. Akasaki
Keyword(s):  
Quantum Wells ◽  
Electric Fields ◽  
High Performance ◽  
Stark Effect ◽  
Electronic Band Structure ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Large Set ◽  
Electronic Band ◽  
Level Splitting

Identification of the electronic band structure in AlInGaN heterostructures is the key issue in high performance light emitter and switching devices. In device-typical GaInN/GaN multiple quantum well samples in a large set of variable composition a clear correspondence of transitions in photo- and electroreflection, as well as photoluminescence is found. The effective band offset across the GaN/GaInN/GaN piezoelectric heterointerface is identified and electric fields from 0.23 - 0.90 MV/cm are directly derived. In the bias voltage dependence a level splitting within the well is observed accompanied by the quantum confined Stark effect. We furthermore find direct correspondence of luminescence bands with reflectance features. This indicates the dominating role of piezoelectric fields in the bandstructure of such typical strained layers.

scholarly journals Piezoelectric Level Splitting in GaInN/GaN Quantum Wells

1998 ◽  
Vol 537 ◽  
Author(s):  
C. Wetzel ◽  
T. Takeuchi ◽  
H. Amano ◽  
I. Akasaki
Keyword(s):  
Quantum Wells ◽  
Electric Fields ◽  
High Performance ◽  
Stark Effect ◽  
Electronic Band Structure ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Large Set ◽  
Electronic Band ◽  
Level Splitting

AbstractIdentification of the electronic band structure in AlInGaN heterostructures is the key issue in high performance light emitter and switching devices. In device-typical GaInN/GaN multiple quantum well samples in a large set of variable composition a clear correspondence of transitions in photo- and electroreflection, as well as photoluminescence is found. The effective band offset across the GaN/GaInN/GaN piezoelectric heterointerface is identified and electric fields from 0.23 - 0.90 MV/cm are directly derived. In the bias voltage dependence a level splitting within the well is observed accompanied by the quantum confined Stark effect. We furthermore find direct correspondence of luminescence bands with reflectance features. This indicates the dominating role of piezoelectric fields in the bandstructure of such typical strained layers.

InGaAs/InP Multiquantum well Structures Grown by Trichloride Vapor Phase Epitaxy

1989 ◽  
Vol 145 ◽  
Author(s):  
K. W. Wang ◽  
V. D. Mattera ◽  
K. Tai ◽  
S. N. G. Chu ◽  
D. D. Roccasecca ◽  
...  
Keyword(s):  
High Speed ◽  
High Performance ◽  
Stark Effect ◽  
Optical Modulators ◽  
Double Crystal ◽  
Cross Sectional ◽  
High Modulation ◽  
Transmission Electron ◽  
Device Applications ◽  
Multiquantum Well

AbstractLong wavelength (l.3pm<X<l.551un) InGaAs/InP multiquantum well (MQW) PIN structures in which the quantum confined Stark effect can be observed, are of particular interest because of their potential for high modulation contrast ratios and high speed operation. The chemistry of trichloride VPE lends itself to the growth of high purity InGaAsP heterostructures which are essential for the realization of high performance optical modulators and switches. In this study, we investigate the application of multi-frit trichloride VPE for the highly uniform epitaxial growth of InGaAs/InP MQW structures on two-inch InP substrates for advanced photonic device applications. The growth of MQW structures with various well thicknesses was studied as was the effect of substrate orientation. The structures have been characterized by infrared absorption and photoluminescence spectroscopy, cross-sectional transmission electron microscopy and double crystal x-ray diffraction.

scholarly journals Interplay of Bias-Driven Charging and the Vibrational Stark Effect in Molecular Junctions

Nano Letters ◽  
2016 ◽  
Vol 16 (2) ◽  
pp. 1104-1109 ◽  
Author(s):  
Yajing Li ◽  
Pavlo Zolotavin ◽  
Peter Doak ◽  
Leeor Kronik ◽  
Jeffrey B. Neaton ◽  
...  
Keyword(s):  
Stark Effect ◽  
Molecular Junctions

High-performance spin rectification in gallium nitride-based molecular junctions with asymmetric edge passivation

2018 ◽  
Vol 124 (21) ◽  
pp. 215102 ◽  
Author(s):  
Tong Chen ◽  
Chengkun Guo ◽  
Quan Li ◽  
Liang Xu ◽  
Lingling Wang ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
High Performance ◽  
Molecular Junctions

scholarly journals Towards low energy consumption integrated photonic circuits based on Ge/SiGe quantum wells

Nanophotonics ◽  
2013 ◽  
Vol 2 (4) ◽  
pp. 279-288 ◽  
Author(s):  
Delphine Marris-Morini ◽  
Papichaya Chaisakul ◽  
Mohamed-Saïd Rouifed ◽  
Jacopo Frigerio ◽  
Daniel Chrastina ◽  
...  
Keyword(s):  
Quantum Wells ◽  
High Performance ◽  
Stark Effect ◽  
Energy Difference ◽  
Light Polarization ◽  
Low Energy ◽  
Carrier Recombination ◽  
Phase Variations ◽  
Indirect Band Gap ◽  
Sige Quantum Wells

AbstractDespite being an indirect bandgap material, germanium (Ge) recently appeared as a material of choice for low power consumption optical link on silicon. Thanks to a low energy difference between direct and indirect energy bandgap, optical transitions around the direct gap can be used to achieve strong electroabsorption or photodetection in a material already used in microelectronics circuits. However, many challenges have to be addressed such as the growth of germanium-rich structures on silicon or the modeling of these structures around both direct and indirect bandgaps. This paper will explore recent achievements in Ge/SiGe quantum wells structures. Quantum confined Stark effect has been studied for different quantum well designs and light polarization. Both absorption and phase variations have been characterized and will be reported. Carrier recombination processes is also an intense research topic, in order to evaluate the competition between direct and indirect band gap emission as a function of temperature. Main results and conclusion will be introduced. Finally, high performance photonic devices (modulator and photodetector) that have already been demonstrated will be presented. At the end the challenges faced by Ge/SiGe QW as a new photonic platform will be presented.

Substituent-mediated quantum interference toward a giant single-molecule conductance variation

2021 ◽  
Author(s):  
Yi-Fan Zhou ◽  
Wen-Yan Chang ◽  
Jing-Zhe Chen ◽  
Jun-Ren Huang ◽  
Jia-Ying Fu ◽  
...  
Keyword(s):  
Single Molecule ◽  
Quantum Interference ◽  
High Performance ◽  
Substituent Effects ◽  
Molecular Junctions ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Transmission Coefficients ◽  
Order Of Magnitude ◽  
Promising Perspective

Abstract Quantum interference (QI) in single molecular junctions shows a promising perspective for realizing conceptual nanoelectronics. However, controlling and modulating the QI remains a big challenge. Herein, two-type substituents at different positions of meta-linked benzene, namely electron-donating methoxy (-OMe) and electron-withdrawing nitryl (-NO2), are designed and synthesized to investigate the substituent effects on QI. The calculated transmission coefficients T(E) indicates that -OMe and -NO2 could remove the antiresonance and destructive quantum interference (DQI)-induced transmission dips at position 2. -OMe could raise the antiresonance energy at position 4 while -NO2 groups removes the DQI features. For substituents at position 5, both of them are nonactive for tuning QI. The conductance measurements by scanning tunneling microscopy break junction (STM-BJ) show a good agreement with the theoretical prediction. More than two order of magnitude single-molecule conductance on/off ratio could be achieved at the different positions of -NO2 substituent groups at room temperature. The present work proves chemical substituents can be used for tuning QI features in single molecular junctions, which provides a feasible way toward realization of high-performance molecular devices.

A High Performance Energy Analyzer for Use in Electron Scanning Microscopy

1969 ◽  
Vol 27 ◽  
pp. 14-15
Author(s):  
A. V. Crewe ◽  
M. Isaacson ◽  
D. Johnson
Keyword(s):  
High Performance ◽  
Vertical Plane ◽  
Median Plane ◽  
Electron Gun ◽  
Uniform Field ◽  
Loss Mechanism ◽  
Electron Scanning Microscopy ◽  
Sector Type ◽  
Double Focusing ◽  
Electron Energy Loss

A double focusing magnetic spectrometer has been constructed for use with a field emission electron gun scanning microscope in order to study the electron energy loss mechanism in thin specimens. It is of the uniform field sector type with curved pole pieces. The shape of the pole pieces is determined by requiring that all particles be focused to a point at the image slit (point 1). The resultant shape gives perfect focusing in the median plane (Fig. 1) and first order focusing in the vertical plane (Fig. 2).

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