Theory of High Field Transport in β-Ga2O3

2019 ◽  
Vol 28 (01n02) ◽  
pp. 1940008
Author(s):  
Krishnendu Ghosh ◽  
Uttam Singisetti
Keyword(s):  
Transport Properties ◽  
Electric Fields ◽  
High Field ◽  
Density Functional ◽  
Electronic Device ◽  
Microscopic Investigation ◽  
Device Performance ◽  
Theoretical Understanding ◽  
External Electric Fields ◽  
Varied Range

We present a comprehensive review of high-field transport properties in an emerging and trending ultra-widebandgap semiconductor β-Ga2O3. The focus is on the theoretical understanding of the microscopic mechanisms that control the dynamics of farfrom-equilibrium electrons. A manifold of density functional calculations and Boltzmann theory based transport formalism unravels the behavior of the electron distribution under a varied range of external electric fields. The key high-field transport properties that govern electronic device performance, like velocity and ionization co-efficients, are enlightened in detail with physical insights. Anisotropies in the above transport co-efficients are probed from the microscopic investigation of bandstructure, electron-phonon interactions, and electron-electron interactions.

Comparison of dielectric and optical responses of chevron ferroelectric liquid crystals

2008 ◽  
Vol 16 (3) ◽  
Author(s):  
W. Jeżwski ◽  
W. Kuczyński ◽  
J. Hoffmann ◽  
D. Dardas
Keyword(s):  
Liquid Crystals ◽  
Electric Fields ◽  
High Field ◽  
Relaxation Processes ◽  
Field Frequency ◽  
Ferroelectric Liquid Crystals ◽  
Low Frequencies ◽  
External Electric Fields ◽  
Optical Responses ◽  
Forming Defects

AbstractAn analysis of consistency of dielectric and optical response methods is carried out for surface stabilized ferroelectric liquid crystals (SSFLC) with chevron geometry. The consistency is found both theoretically and experimentally for weak external electric fields of intermediate frequencies, for which the response of SSFLC is dominated by collective relaxation processes due to azimuthal reorientation of molecules arranging chevron layers. The methods are experimentally shown to lack consistency within very low, relatively low, and high field-frequency ranges. The disagreement appearing at relatively low frequencies is argued to be a consequence of different recording by dielectric and optical techniques the dynamics of zig-zag walls, forming defects in chevron structure.

Density functional theory study of electric field effects on the isomerization of a photochromic molecular switch based on 1,2-dithienylethene

2014 ◽  
Vol 92 (4) ◽  
pp. 317-323 ◽  
Author(s):  
Ehsan Zahedi ◽  
Majid Mozaffari ◽  
Fereshteh-Sadat Karimi ◽  
Azita Nouri
Keyword(s):  
Density Functional Theory ◽  
Electric Field ◽  
Closed Form ◽  
External Electric Field ◽  
Electric Fields ◽  
Density Functional ◽  
Open Form ◽  
Functional Theory ◽  
External Electric Fields ◽  
Homo Lumo

Structural and electronic properties of 1,2-bis(5-methyl-[2,2′-bithiophen]-4-yl)cyclopent-1-ene in closed form and open form under various external electric field with strengths, 0, 10 × 10−4, 20 × 10−4, 30 × 10−4, 40 × 10−4, and 50 × 10−4 a.u., were studied using the DFT-B3LYP/6-31G* method. As a positive index, structural parameters, length of the photoisomers, and the electronic spatial extents are almost stable at different external electric fields. The UV-Vis electronic spectrum based on time-dependent density functional theory indicated that the HOMO → LUMO transition in the closed form under different electric field strengths is strongly allowed, whereas is very weak in the open form. Electronic response parameters such as the HOMO−LUMO gap, electric dipole moment, and polarizability showed that electric conductivity of the closed form at different field strengths is greater than in the open form. Results of electronic density of states show that at high external electric field, the conductivity of the open form and closed form will be probably equal and switching behavior cannot be observed. Isomerization of the closed form to the open form at different external electric fields can be considered as exothermic and spontaneous.

In situ TEM measurements of the electrical properties of interface dislocations

1992 ◽  
Vol 50 (2) ◽  
pp. 1338-1339
Author(s):  
F. M. Ross ◽  
R. Hull ◽  
D. Bahnck ◽  
J. C. Bean ◽  
L. J. Peticolas ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Electronic Device ◽  
In Situ Tem ◽  
Device Performance ◽  
Misfit Dislocations ◽  
Electrical Characteristics ◽  
Strained Layer ◽  
Transmission Electron ◽  
Interfacial Dislocations

We describe an investigation of the electrical properties of interfacial dislocations in strained layer heterostructures. We have been measuring both the structural and electrical characteristics of strained layer p-n junction diodes simultaneously in a transmission electron microscope, enabling us to correlate changes in the electrical characteristics of a device with the formation of dislocations.The presence of dislocations within an electronic device is known to degrade the device performance. This degradation is of increasing significance in the design and processing of novel strained layer devices which may require layer thicknesses above the critical thickness (hc), where it is energetically favourable for the layers to relax by the formation of misfit dislocations at the strained interfaces. In order to quantify how device performance is affected when relaxation occurs we have therefore been investigating the electrical properties of dislocations at the p-n junction in Si/GeSi diodes.

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 Emulsions in external electric fields

2021 ◽  
pp. 102455
Author(s):  
Johan Sjöblom ◽  
Sameer Mhatre ◽  
Sébastien Simon ◽  
Roar Skartlien ◽  
Geir Sørland
Keyword(s):  
Electric Fields ◽  
External Electric Fields
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