scholarly journals Energy Gaps in BN/GNRs Planar Heterostructure

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5079
Author(s):  
Jinyue Guan ◽  
Lei Xu
Keyword(s):  
Phase Transition ◽  
Boron Nitride ◽  
Band Gap ◽  
Lattice Mismatch ◽  
Tight Binding ◽  
Graphene Nanoribbon ◽  
Band Gaps ◽  
Energy Gaps ◽  
Local Potentials

Using the tight-binding approach, we study the band gaps of boron nitride (BN)/ graphene nanoribbon (GNR) planar heterostructures, with GNRs embedded in a BN sheet. The width of BN has little effect on the band gap of a heterostructure. The band gap oscillates and decreases from 2.44 eV to 0.26 eV, as the width of armchair GNRs, nA, increases from 1 to 20, while the band gap gradually decreases from 3.13 eV to 0.09 eV, as the width of zigzag GNRs, nZ, increases from 1 to 80. For the planar heterojunctions with either armchair-shaped or zigzag-shaped edges, the band gaps can be manipulated by local potentials, leading to a phase transition from semiconductor to metal. In addition, the influence of lattice mismatch on the band gap is also investigated.

Tuning the Electronic Properties of Symetrical and Asymetrical Boron Nitride Passivated Graphene Nanoribbons: Density Function Theory

2018 ◽  
Vol 54 ◽  
pp. 35-41
Author(s):  
Mohammad Bashirpour ◽  
Ali Kefayati ◽  
Mohammadreza Kolahdouz ◽  
Hossein Aghababa
Keyword(s):  
Boron Nitride ◽  
Band Gap ◽  
Density Function ◽  
Function Theory ◽  
Graphene Nanoribbons ◽  
Graphene Nanoribbon ◽  
Density Function Theory ◽  
Band Gaps ◽  
Asymmetrical Structure ◽  
Armchair Graphene

—Density function theory (DFT) based simulation combined with non-equilibrium green function (NEGF) was used to theoretically investigate electrical properties of symmetrical and asymmetrical boron nitride (BN) passivated graphene nanoribbons. Using density function theory method, it is demonstrated that the band gap of armchair (A) graphene nanoribbon (GNR) can be widened with boron nitride passivation. five symmetrical and five asymmetrical structures were considered, for which we obtained band gaps from 0.45 eV to 2 eV for symmetrical structures and 0.3 eV to 1.5 eV for asymmetrical structures. For the same width of graphene nanoribbon, our results showed that asymmetrical structure has a smaller band gap and almost the same conductance in comparison with the symmetrical one. Finally, comparison between the asymmetrical structure and the hydrogenated armchair graphene (h-AGNR) nanoribbon showed that, hBN-AGNR exhibited a higher conductance compared to an h-AGNR for the same width of GNR.

scholarly journals Carbon-Based Band Gap Engineering in the h-BN Analytical Modeling

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1026
Author(s):  
Mohammad Taghi Ahmadi ◽  
Ahmad Razmdideh ◽  
Seyed Saeid Rahimian Koloor ◽  
Michal Petrů
Keyword(s):  
Boron Nitride ◽  
Band Gap ◽  
Density Functional ◽  
Hexagonal Boron Nitride ◽  
Tight Binding ◽  
Band Gap Energy ◽  
Specific Structure ◽  
Partial Substitution ◽  
Generalized Gradient ◽  
Complete Replacement

The absence of a band gap in graphene is a hindrance to its application in electronic devices. Alternately, the complete replacement of carbon atoms with B and N atoms in graphene structures led to the formation of hexagonal boron nitride (h-BN) and caused the opening of its gap. Now, an exciting possibility is a partial substitution of C atoms with B and N atoms in the graphene structure, which caused the formation of a boron nitride composite with specified stoichiometry. BC2N nanotubes are more stable than other triple compounds due to the existence of a maximum number of B–N and C–C bonds. This paper focused on the nearest neighbor’s tight-binding method to explore the dispersion relation of BC2N, which has no chemical bond between its carbon atoms. More specifically, the band dispersion of this specific structure and the effects of energy hopping in boron–carbon and nitrogen–carbon atoms on the band gap are studied. Besides, the band structure is achieved from density functional theory (DFT) using the generalized gradient approximations (GGA) approximation method. This calculation shows that this specific structure is semimetal, and the band gap energy is 0.167 ev.

UNIFORM BENDING EFFECT ON ELECTRONIC PROPERTIES OF BORON NITRIDE NANORIBBONS: A COMPUTATIONAL INVESTIGATION

Nano LIFE ◽  
2012 ◽  
Vol 02 (02) ◽  
pp. 1240005
Author(s):  
YUNLONG LIAO ◽  
ZHONGFANG CHEN
Keyword(s):  
Boron Nitride ◽  
Band Gap ◽  
Electronic Properties ◽  
First Principles ◽  
Wide Band ◽  
Band Gaps ◽  
Computational Investigation ◽  
Wide Band Gap ◽  
Bending Effect ◽  
Boron Nitride Nanoribbons

First-principles computations were performed to investigate the uniform bending effect on the electronic properties of armchair boron nitride nanoribbons (aBNNRs) with experimentally obtained width. For both bare and hydrogen-terminated aBNNRs, the band gaps only slightly depend on the uniform bending. The insensitivity of the band structures of BNNRs to the uniform bending makes them ideal materials when their wide band gap character is desired.

Transition of wide-band gap semiconductor h-BN(BN)/P heterostructure via single-atom-embedding

2020 ◽  
Vol 8 (28) ◽  
pp. 9755-9762 ◽  
Author(s):  
Itsuki Miyazato ◽  
Tanveer Hussain ◽  
Keisuke Takahashi
Keyword(s):  
Boron Nitride ◽  
Band Gap ◽  
First Principles ◽  
Wide Band ◽  
Band Gaps ◽  
Single Atom ◽  
First Principles Calculations ◽  
Optoelectronic Materials ◽  
Wide Band Gap

The band gaps in boron nitride/phosphorene (h-BN/P) heterostructures are investigated by single-atom-embedding via first principles calculations. The modified heterostructures are potential optoelectronic materials with tunable band gaps.

Influence of Structural Parameters to Engineer the Band Gaps in Ternary Pnictide Semiconductors - Theory as a Tool

2007 ◽  
Vol 124-126 ◽  
pp. 57-60 ◽  
Author(s):  
Rita John
Keyword(s):  
Band Gap ◽  
Energy Gap ◽  
Structural Parameters ◽  
Tight Binding ◽  
Band Gaps ◽  
Theoretical Tool ◽  
Linear Muffin Tin Orbital

The band gap anomaly exhibited by ABC2 : A = Cd; B = Si,Ge,Sn; C = P,As pnictides with respect to their binary analogs GaP, Ga0.5In0.5P, InP, GaAs, Ga0.5In0.5As, InAs is studied using Tight Binding Linear Muffin Tin Orbital (TBLMTO) method as an investigating theoretical tool. The influence of the structural parameters, η and u are analyzed to enable one to tune energy gap to make tailor made compounds.

scholarly journals Parity-time phase transition in photonic crystals with $$C_{6v}$$ symmetry

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jeng-Rung Jiang ◽  
Wei-Ting Chen ◽  
Ruey-Lin Chern
Keyword(s):  
Phase Transition ◽  
Photonic Crystals ◽  
Band Gap ◽  
Tight Binding ◽  
Symmetric System ◽  
Complex Conjugate ◽  
Edge States ◽  
Tight Binding Approximation ◽  
Common Band ◽  
Gain And Loss

Abstract We investigate the parity-time (PT) phase transition in photonic crystals with $$C_{6v}$$ C 6 v symmetry, with balanced gain and loss on dielectric rods in the triangular lattice. A two-level non-Hermitian model that incorporates the gain and loss in the tight-binding approximation was employed to describe the dispersion of the PT symmetric system. In the unbroken PT phase, the double Dirac cone feature associated with the $$C_{6v}$$ C 6 v symmetry is preserved, with a frequency shift of second order due to the presence of gain and loss. The helical edge states with real eigenfrequencies can exist in the common band gap for two topologically distinct lattices. In the broken PT phase, the non-Hermitian perturbation deforms the dispersion by merging the frequency bands into complex conjugate pairs and forming the exceptional contours that feature the PT phase transition. In this situation, the band gap closes and the edge states are mixed with the bulk states.

THE OPTICAL GAP IN TERNARY PHOSPHIDES

1988 ◽  
Vol 02 (02) ◽  
pp. 221-236
Author(s):  
JEREMY K. BURDETT ◽  
BARRY A. CODDENS
Keyword(s):  
Transition Metal ◽  
Band Gap ◽  
Valence Band ◽  
Conduction Band ◽  
Tight Binding ◽  
Band Gaps ◽  
Optical Gap ◽  
Cation Size ◽  
D Orbitals

Some factors are described which influence the band gap in ternary phosphides with superstructures of the rocksalt, zincblende and perovskite arrangements. The gap is strongly controlled by cation size, since as these atoms become smaller the phosphorus sheets are pulled closer together with an increase in energy of the top of the valence band via P-P overlap. The electronegativity of the cations are also important since the bottom of the conduction band is largely composed of metal d orbitals in the case of a transition metal. It is shown how good estimates of observed band gaps in ZnSiP 2 and ZnGeP 2 may be obtained by the inclusion of d orbitals on the anions in the tight-binding calculations.

scholarly journals Edge-state influence on high-order harmonic generation in topological nanoribbons

2021 ◽  
Vol 75 (6) ◽  
Author(s):  
Christoph Jürß ◽  
Dieter Bauer
Keyword(s):  
Phase Transition ◽  
Band Gap ◽  
Harmonic Generation ◽  
Tight Binding ◽  
High Order ◽  
Edge States ◽  
Binding Parameters ◽  
High Order Harmonic Generation ◽  
Tight Binding Approximation ◽  
High Order Harmonic

Abstract The high-order harmonic generation in finite topological nanoribbons is investigated using a tight-binding approximation. The narrow, two-dimensional ribbons consist of hexagonal structures. A topological phase transition is defined by a sudden change of the topological invariant. In the bulk, this kind of phase transition might occur if an existing band gap closes and reopens again. Through the bulk-boundary correspondence, this is related to the emergence of topologically protected edge states in the respective finite systems. For the finite ribbons studied in this work, the variation of the tight-binding parameters leads to the emergence of two edge states after the closing of the band gap. The energies of those edge states as functions of the tight-binding parameters display crossings and avoided crossings, which influence the high-harmonic spectra. Graphic Abstract

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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