scholarly journals Probing dynamic behavior of electric fields and band diagrams in complex semiconductor heterostructures

2018 ◽  
Vol 123 (2) ◽  
pp. 024301 ◽  
Author(s):  
Yury Turkulets ◽  
Ilan Shalish
Keyword(s):  
Dynamic Behavior ◽  
Electric Fields ◽  
Semiconductor Heterostructures ◽  
Complex Semiconductor

On the dynamic behavior of piezoelectric active repair by the boundary element method

2011 ◽  
Vol 22 (18) ◽  
pp. 2137-2146 ◽  
Author(s):  
A. Alaimo ◽  
A. Milazzo ◽  
C. Orlando
Keyword(s):  
Fracture Mechanics ◽  
Boundary Element ◽  
Dynamic Behavior ◽  
Electric Fields ◽  
Dynamic Stress ◽  
Bonding Layer ◽  
Dynamic Stress Intensity Factors ◽  
Tangential Stiffness ◽  
Elastic Interface ◽  
Cracked Structures

The dynamic behavior of piezoelectric active repair bonded on cracked structures is analyzed in this article. The boundary element code used to perform the simulations is implemented in the framework of piezoelectricity in order to model the coupling between the elastic and the electric fields, which represents the most important feature of piezoelectric media. The fracture mechanics problem, i.e. the crack, as well as the bonding layer between the host structure and the active patch is modeled by means of the multidomain technique provided with an interface spring model. More particularly, the spring interface model allows considering the bonding layer as a zero-thickness elastic ply characterized by normal and tangential stiffness constants. The crack is also modeled as an elastic interface characterized by vanishing stiffness. The dual reciprocity method (DRM) has been used in the present time-dependent application for the approximation of the domain inertia terms. Numerical analyses have been carried out in order to characterize the dynamic repairing mechanism of the assembled structure by means of the computation of the dynamic stress intensity factors and discussions are presented to highlight the effect of the inertial forces on the fracture mechanics behavior of the overall assembled structure.

scholarly journals Dynamic behavior of nematic liquid crystal mixtures with quantum dots in electric fields

2018 ◽  
Vol 9 ◽  
pp. 399-406 ◽  
Author(s):  
Emil Petrescu ◽  
Cristina Cirtoaje ◽  
Octavian Danila
Keyword(s):  
Experimental Data ◽  
Quantum Dots ◽  
Relaxation Time ◽  
Dynamic Behavior ◽  
Electric Fields ◽  
Mass Fraction ◽  
Liquid Crystalline ◽  
Continuum Theory ◽  
Dynamic Measurements ◽  
Elastic Continuum

The dynamic behavior of a mixture consisting of liquid crystalline 4-cyano-4’-pentylbiphenyl (5CB) and CdSe/ZnS quantum dots in electric fields was theoretically studied. The model was based on elastic continuum theory considering the interaction of the nematic molecules with the surrounding molecules, with the quantum dots and with the electric field. Experimental data obtained by dynamic measurements on a sample containing 0.89% (mass fraction) of CdSe/ZnS quantum dots revealed a decrease of the relaxation time compared to pure 5CB.

scholarly journals A Theoretical Treatment of THz Resonances in Semiconductor GaAs p–n Junctions

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2412 ◽  
Author(s):  
Mohsen Janipour ◽  
I. Burc Misirlioglu ◽  
Kursat Sendur
Keyword(s):  
Dielectric Function ◽  
Electric Fields ◽  
Semiconductor Heterostructures ◽  
Theoretical Treatment ◽  
Low Loss ◽  
Depletion Zone ◽  
Charge Densities ◽  
As Doping ◽  
Effective Masses ◽  
Spatially Varying

Semiconductor heterostructures are suitable for the design and fabrication of terahertz (THz) plasmonic devices, due to their matching carrier densities. The classical dispersion relations in the current literature are derived for metal plasmonic materials, such as gold and silver, for which a homogeneous dielectric function is valid. Penetration of the electric fields into semiconductors induces locally varying charge densities and a spatially varying dielectric function is expected. While such an occurrence renders tunable THz plasmonics a possibility, it is crucial to understand the conditions under which propagating resonant conditions for the carriers occur, upon incidence of an electromagnetic radiation. In this manuscript, we derive a dispersion relation for a p–n heterojunction and apply the methodology to a GaAs p–n junction, a material of interest for optoelectronic devices. Considering symmetrically doped p- and n-type regions with equal width, the effect of certain parameters (such as doping and voltage bias) on the dispersion curve of the p–n heterojunction were investigated. Keeping in sight the different effective masses and mobilities of the carriers, we were able to obtain the conditions that yield identical dielectric functions for the p- and n-regions. Our results indicated that the p–n GaAs system can sustain propagating resonances and can be used as a layered plasmonic waveguide. The conditions under which this is feasible fall in the frequency region between the transverse optical phonon resonance of GaAs and the traditional cut-off frequency of the diode waveguide. In addition, our results indicated when the excitation was slightly above the phonon resonance frequency, the plasmon propagation attained low-loss characteristics. We also showed that the existence or nonexistence of the depletion zone between the p- and n- interfaces allowed certain plasmon modes to propagate, while others decayed rapidly, pointing out the possibility for a design of selective filters.

Ellipsometric analysis of built‐in electric fields in semiconductor heterostructures

1987 ◽  
Vol 51 (10) ◽  
pp. 770-772 ◽  
Author(s):  
Paul G. Snyder ◽  
Jae E. Oh ◽  
John A. Woollam ◽  
R. E. Owens
Keyword(s):  
Electric Fields ◽  
Semiconductor Heterostructures

Control of Metal Alloy Oxidation with Electric Fields

1973 ◽  
Vol 31 ◽  
pp. 164-165
Author(s):  
R. R. Dils ◽  
P. S. Follansbee
Keyword(s):  
Electric Fields ◽  
Oxidation Process ◽  
Base Alloy ◽  
Oxide Surface ◽  
Platinum Electrodes ◽  
Insulating Layer ◽  
Iron Base Alloy ◽  
Alloy Oxidation ◽  
Aluminum Oxide Layer ◽  
And Control

Electric fields have been applied across oxides growing on a high temperature alloy and control of the oxidation of the material has been demonstrated. At present, three-fold increases in the oxidation rate have been measured in accelerating fields and the oxidation process has been completely stopped in a retarding field.The experiments have been conducted with an iron-base alloy, Pe 25Cr 5A1 0.1Y, although, in principle, any alloy capable of forming an adherent aluminum oxide layer during oxidation can be used. A specimen is polished and oxidized to produce a thin, uniform insulating layer on one surface. Three platinum electrodes are sputtered on the oxide surface and the specimen is reoxidized.

Electron-Mirror Microscopic Aspects of Ferroelectric Domains of BaTiO3 And Ca2Sr (C2H5CO2)6

1970 ◽  
Vol 28 ◽  
pp. 478-479
Author(s):  
Teruo Someya ◽  
Jinzo Kobayashi
Keyword(s):  
Surface Layer ◽  
Electric Fields ◽  
Quantitative Study ◽  
Recent Progress ◽  
Ferroelectric Domain ◽  
Resolving Power ◽  
Surface Pattern ◽  
Crystal Surfaces ◽  
One Dimensional ◽  
Ferroelectric Domains

Recent progress in the electron-mirror microscopy (EMM), e.g., an improvement of its resolving power together with an increase of the magnification makes it useful for investigating the ferroelectric domain physics. English has recently observed the domain texture in the surface layer of BaTiO3. The present authors ) have developed a theory by which one can evaluate small one-dimensional electric fields and/or topographic step heights in the crystal surfaces from their EMM pictures. This theory was applied to a quantitative study of the surface pattern of BaTiO3).

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