Perforation-rotation based approach for band gap creation and enlargement in low porosity architected materials

2020 ◽  
Vol 245 ◽  
pp. 112331
Author(s):  
Xiangyu Tian ◽  
Wenjiong Chen ◽  
Renjing Gao ◽  
Shutian Liu ◽  
Jiaxing Wang
Keyword(s):  
Band Gap ◽  
Gap Creation ◽  
Low Porosity

ELECTRONIC STRUCTURE OF GRAPHENE NANORIBBONS SUBJECTED TO TWIST AND NONUNIFORM STRAIN

2011 ◽  
Vol 20 (01) ◽  
pp. 153-160 ◽  
Author(s):  
A. DOBRINSKY ◽  
A. SADRZADEH ◽  
B. I. YAKOBSON ◽  
J. XU
Keyword(s):  
Band Gap ◽  
Density Functional ◽  
Graphene Nanoribbons ◽  
Tight Binding ◽  
Tight Binding Approximation ◽  
Functional Theory ◽  
Gap Opening ◽  
Gap Creation ◽  
Band Gap Modulation ◽  
Twisted Graphene

Graphene nanoribbons exhibit band gap modulation when subjected to strain. While band gap creation has been theoretically investigated for uniaxial strains, other deformations such as nanoribbon twist have not been considered. Our main objective in this paper is to explore band gap opening in twisted graphene nanoribbons that have metallic properties under tight-binding approximation. While simple considerations based on the Hückel model allow to conclude that zigzag graphene nanoribbons exhibit no band gap when subjected to twist, the Hückel model overall may be inaccurate for band gap prediction in metallic nanoribbons. We utilize Density Functional Theory Tight-Binding Approximation together with a requirement that energy of twisted nanoribbons is minimized to evaluate band gap of metalic armchair nanoribbons. Besides considering twisting deformations, we also explore the possibility of creating band gap when graphene nanoribbons are subject to inhomogeneous deformation such as sinusoidal deformations.

scholarly journals Band‐gap creation using quasiordered structures based on sonic crystals

2006 ◽  
Vol 119 (5) ◽  
pp. 3410-3411
Author(s):  
Vicent Romero Garcia ◽  
Elies Fuster Garcia ◽  
Juan V. Sanchez‐Perez ◽  
Luis M. Garcia‐Raffi ◽  
Enrique A. Sanchez‐Perez
Keyword(s):  
Band Gap ◽  
Sonic Crystals ◽  
Gap Creation

scholarly journals Targeted band gap creation using mixed sonic crystal arrays including resonators and rigid scatterers

2007 ◽  
Vol 90 (24) ◽  
pp. 244104 ◽  
Author(s):  
E. Fuster-Garcia ◽  
V. Romero-García ◽  
J. V. Sánchez-Pérez ◽  
L. M. García-Raffi
Keyword(s):  
Band Gap ◽  
Sonic Crystal ◽  
Gap Creation

scholarly journals Band gap creation using quasiordered structures based on sonic crystals

2006 ◽  
Vol 88 (17) ◽  
pp. 174104 ◽  
Author(s):  
V. Romero-García ◽  
E. Fuster ◽  
L. M. García-Raffi ◽  
E. A. Sánchez-Pérez ◽  
M. Sopena ◽  
...  
Keyword(s):  
Band Gap ◽  
Sonic Crystals ◽  
Gap Creation

TEM and cathodoluminescence of precipitates in II-VI semiconductors

1988 ◽  
Vol 46 ◽  
pp. 488-489
Author(s):  
Joanna L. Batstone
Keyword(s):  
Crystal Growth ◽  
Band Gap ◽  
Local Strain ◽  
Wide Band ◽  
Optoelectronic Device ◽  
Wide Band Gap ◽  
Bulk Crystal Growth ◽  
Transmission Electron ◽  
Device Applications ◽  
Stoichiometry Control

Interest in II-VI semiconductors centres around optoelectronic device applications. The wide band gap II-VI semiconductors such as ZnS, ZnSe and ZnTe have been used in lasers and electroluminescent displays yielding room temperature blue luminescence. The narrow gap II-VI semiconductors such as CdTe and HgxCd1-x Te are currently used for infrared detectors, where the band gap can be varied continuously by changing the alloy composition x.Two major sources of precipitation can be identified in II-VI materials; (i) dopant introduction leading to local variations in concentration and subsequent precipitation and (ii) Te precipitation in ZnTe, CdTe and HgCdTe due to native point defects which arise from problems associated with stoichiometry control during crystal growth. Precipitation is observed in both bulk crystal growth and epitaxial growth and is frequently associated with segregation and precipitation at dislocations and grain boundaries. Precipitation has been observed using transmission electron microscopy (TEM) which is sensitive to local strain fields around inclusions.

Structural properties of GaAs/InGaAs/GaAs (001) and InGaAs/GaAs (001) heterostructures and correlation with electronic properties

1990 ◽  
Vol 48 (4) ◽  
pp. 602-603
Author(s):  
J.M. Bonar ◽  
R. Hull ◽  
R. Malik ◽  
R. Ryan ◽  
J.F. Walker
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Gaas Substrate ◽  
Critical Thickness ◽  
Lattice Mismatch ◽  
Band Offset ◽  
Misfit Dislocations ◽  
Gaas Substrates ◽  
Gaas Structure ◽  
Low X

In this study we have examined a series of strained heteropeitaxial GaAs/InGaAs/GaAs and InGaAs/GaAs structures, both on (001) GaAs substrates. These heterostructures are potentially very interesting from a device standpoint because of improved band gap properties (InAs has a much smaller band gap than GaAs so there is a large band offset at the InGaAs/GaAs interface), and because of the much higher mobility of InAs. However, there is a 7.2% lattice mismatch between InAs and GaAs, so an InxGa1-xAs layer in a GaAs structure with even relatively low x will have a large amount of strain, and misfit dislocations are expected to form above some critical thickness. We attempt here to correlate the effect of misfit dislocations on the electronic properties of this material.The samples we examined consisted of 200Å InxGa1-xAs layered in a hetero-junction bipolar transistor (HBT) structure (InxGa1-xAs on top of a (001) GaAs buffer, followed by more GaAs, then a layer of AlGaAs and a GaAs cap), and a series consisting of a 200Å layer of InxGa1-xAs on a (001) GaAs substrate.

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