Energy Band Gap Modification of Graphene Deposited on a Multilayer Hexagonal Boron Nitride Substrate

2012 ◽  
Vol 1407 ◽  
Author(s):  
Celal Yelgel ◽  
Gyaneshwar P. Srivastava
Keyword(s):  
Boron Nitride ◽  
Band Gap ◽  
Energy Band ◽  
Density Functional ◽  
Hexagonal Boron Nitride ◽  
Monolayer Graphene ◽  
Stable Configuration ◽  
Equilibrium Geometry ◽  
Energy Band Gap ◽  
Electron Speed

ABSTRACTThe equilibrium geometry and electronic structure of graphene deposited on a multilayer hexagonal boron nitride (h-BN) substrate has been investigated using the density functional and pseudopotential theories. We found that the energy band gap for the interface between a monolayer graphene (MLG) and a monolayer BN (MLBN) lies between 47 and 62 meV, depending on the relative orientations of the layers. In the most energetically stable configuration the binding energy is found to be approximately 40 meV per C atom. Slightly away from the Dirac point, the dispersion curve is linear, with the electron speed almost identical to that for isolated graphene. The dispersion relation becomes reasonably quadratic for the interface between MLG and 4-layer-BN, with a relative effective mass of 0.0047. While the MLG/MLBN superlattice is metallic, the thinnest armchair nanoribbon of MLG/MLBN interface is semiconducting with a gap of 1.84 eV.

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.

Density Functional Theory Study on Energy Band Gap of Armchair Silicene Nanoribbons with Periodic Nanoholes

MRS Advances ◽  
2016 ◽  
Vol 1 (22) ◽  
pp. 1613-1618 ◽  
Author(s):  
Sadegh Mehdi Aghaei ◽  
Irene Calizo
Keyword(s):  
Density Functional Theory ◽  
Band Gap ◽  
Energy Band ◽  
Quantum Confinement ◽  
Density Functional ◽  
Quantum Confinement Effect ◽  
Density Functional Theory Study ◽  
Energy Band Gap ◽  
Functional Theory ◽  
Silicene Nanoribbons

ABSTRACTIn this study, density functional theory (DFT) is employed to investigate the electronic properties of armchair silicene nanoribbons perforated with periodic nanoholes (ASiNRPNHs). The dangling bonds of armchair silicene nanoribbons (ASiNR) are passivated by mono- (:H) or di-hydrogen (:2H) atoms. Our results show that the ASiNRs can be categorized into three groups based on their width: W = 3P − 1, 3P, and 3P + 1, P is an integer. The band gap value order changes from “EG (3P − 1) < EG (3P) < EG (3P + 1)” to “EG (3P + 1) < EG (3P − 1) < EG (3P)” when edge hydrogenation varies from mono- to di-hydrogenated. The energy band gap values for ASiNRPNHs depend on the nanoribbons width and the repeat periodicity of the nanoholes. The band gap value of ASiNRPNHs is larger than that of pristine ASiNRs when repeat periodicity is even, while it is smaller than that of pristine ASiNRs when repeat periodicity is odd. In general, the value of energy band gap for ASiNRPNHs:2H is larger than that of ASiNRPNHs:H. So a band gap as large as 0.92 eV is achievable with ASiNRPNHs of width 12 and repeat periodicity of 2. Furthermore, creating periodic nanoholes near the edge of the nanoribbons cause a larger band gap due to a strong quantum confinement effect.

Electronic Properties of Calcium and Zirconium Co-Doped BaTiO3

2020 ◽  
Vol 1010 ◽  
pp. 308-313
Author(s):  
Akeem Adekunle Adewale ◽  
Abdullah Chik ◽  
Ruhiyuddin Mohd Zaki
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Density Of States ◽  
Energy Band ◽  
Density Functional ◽  
Partial Density ◽  
Total Density ◽  
Energy Band Gap ◽  
Wide Energy ◽  
Direct Band

Barium titanate (BaTiO3) is a perovskite based oxides with many potential application in electronic devices. From experimental report BaTiO3 has wide energy band gap of about 3.4 eV which by doped with Ca and Zr at A- and B- sites respectively can enhance their piezoelectric properties. Using first principles method within the density functional theory (DFT) as implement in Quantum Espresso (QE) with the plane wave pseudo potential function, the influence of the Ca and Zr doping in BaTiO3 are studied via electronic properties: band structure, total density of states (TDOS) and partial density of states (PDOS). The energy band gap calculated was underestimation which is similar to other DFT work. Two direct band gap where observed in Ba0.875Ca0.125Ti0.875Zr0.125O3 sample at Γ- Γ (2.31 eV) and X- X (2.35 eV) symmetry point.

Tuning Electronic and Structural Properties of Triple Layers of Intercalated Graphene and Hexagonal Boron Nitride: An Ab-initio Study.

2011 ◽  
Vol 1307 ◽  
Author(s):  
Samir S. Coutinho ◽  
David L. Azevedo ◽  
Douglas S. Galvão
Keyword(s):  
Boron Nitride ◽  
Electric Field ◽  
Ab Initio ◽  
Band Gap ◽  
External Electric Field ◽  
Structural Properties ◽  
Density Functional ◽  
Hexagonal Boron Nitride ◽  
Electronic And Structural Properties ◽  
Gap Values

ABSTRACTRecently, several experiments and theoretical studies demonstrated the possibility of tuning or modulating band gap values of nanostructures composed of bi-layer graphene, bi-layer hexagonal boron-nitride (BN) and hetero-layer combinations. These triple layers systems present several possibilities of stacking. In this work we report an ab initio (within the formalism of density functional theory (DFT)) study of structural and electronic properties of some of these stacked configurations. We observe that an applied external electric field can alter the electronic and structural properties of these systems. With the same value of the applied electric field the band gap values can be increased or decreased, depending on the layer stacking sequences. Strong geometrical deformations were observed. These results show that the application of an external electric field perpendicular to the stacked layers can effectively be used to modulate their inter-layer distances and/or their band gap values.

scholarly journals STUDY OF TiO2 NANOPARTICLES’ STRUCTURE USING DENSITY FUNCTIONAL THEORY BASED TIGHT BINDING METHOD

2019 ◽  
Vol 1 (27) ◽  
pp. 79-85
Author(s):  
Hung Thanh Phan
Keyword(s):  
Density Functional Theory ◽  
Band Gap ◽  
Tio2 Nanoparticles ◽  
Energy Band ◽  
Density Functional ◽  
Anatase Phase ◽  
Tight Binding ◽  
Energy Band Gap ◽  
Functional Theory ◽  
Practical Applications

The different structure and size of TiO2 nanoparticles ranging from 0.8 nm to 2.7 nm with two different phases of anatase and rutile were studied by Density  Functional theory based Tight Binding (DFTB) method. The results showed that the stability of the rutile phase was better than that of the anatase phase. Based on calculation of the electronic properties of particles, the energy band gap of rutile particles was comparable to that of bulk structure. In contrast, the energy band gap of the anatase changed irregularly. Moreover, the formation energy that was used for forming the particles was inversely proportional to their size based on computation of energy. The results provided useful instructions for practical applications in fabrication of TiO2 nanoparticles.

Atomic and Electronic Structure of Multilayer Graphene on a Monolayer Hexagonal Boron Nitride

2013 ◽  
Vol 1549 ◽  
pp. 65-70
Author(s):  
Celal Yelgel ◽  
Gyaneshwar P. Srivastava
Keyword(s):  
Boron Nitride ◽  
Density Functional ◽  
Local Density ◽  
Hexagonal Boron Nitride ◽  
Binding Energies ◽  
Multilayer Graphene ◽  
Functional Theory ◽  
Electron Speed ◽  
The Density Functional Theory ◽  
Trilayer Graphene

ABSTRACTThe atomic and electronic structures of multilayer graphene on a monolayer boron nitride (MLBN) have been investigated by using the pseudopotential method and the local density approximation (LDA) of the density functional theory (DFT). We show that the LDA energy band gap can be tuned in the range 41-278 meV for a multilayer graphene by using MLBN as a substrate. The dispersion of the π/π* bands slightly away from the K point is linear with the electron speed of 0.9×106 and 0.93×106 for graphene (MLG)/MLBN and ABA trilayer graphene (TLG)/MLBN systems, respectively. This behaviour becomes quadratic with a relative effective mass of 0.0021 for the bilayer graphene (BLG)/MLBN system. The calculated binding energies are in the range of 10-43 meV per C atom.

First-Principles Study of Energy Band Gap of Graphene-Like B-C-N by Strain

2012 ◽  
Vol 476-478 ◽  
pp. 1313-1317 ◽  
Author(s):  
Xin Miao Xu ◽  
Yu Lu
Keyword(s):  
Band Gap ◽  
First Principles ◽  
Energy Band ◽  
Tensile Deformation ◽  
Electronic Band Structure ◽  
Strain Engineering ◽  
Monolayer Graphene ◽  
Energy Band Gap ◽  
Electronic Band ◽  
Hexagonal Sheet

We report a first-principles investigation on BN dopped monolayer graphene sheet and examined the electronic band structure and band gaps in equilibrium state and under strain. The obtained results reveal that the doping of B-N pairs on the hexagonal sheet can open the gap at the Dirac-like point. With heavy doping and more B-N bonds the energy bad gap is found to be larger. Upon tensile deformation, the dopped BCN monolayer sheet represents a strong anisotropic stress-strain relation. Detailed strain-gap relation investigation reveals that the energy band gap presents desperate variation trends for strain applied along and direction. Versatile band-gap modulation schemes can then be obtained through direction-dependent strain engineering of the BCN nanosheet..

scholarly journals Electronic Properties of Hydrogenated Hexagonal Boron Nitride (h-BN): DFT Study

2019 ◽  
Vol 4 (2) ◽  
pp. 72-79
Author(s):  
B. Chettri ◽  
P. K. Patra ◽  
Sunita Srivastava ◽  
Lalhriatzuala ◽  
Lalthakimi Zadeng ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Band Gap ◽  
Electronic Properties ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Hexagonal Boron Nitride ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
The Density Functional Theory

In this work, we have constructed the hydrogenated hexagonal boron nitride (h-BN) by placing hydrogen atom at different surface sites. The possibility of hydrogen adsorption on the BN surface has been estimated by calculating the adsorption energy. The electronic properties were calculated for different hydrogenated BNs. The theoretical calculation was based on the Density Functional Theory (DFT). The electron-exchange energy was treated within the most conventional functional called generalized gradient approximation. The calculated band gap of pure BN is 3.80 eV. The adsorption of two H-atoms at two symmetrical sites of B and N sites reduces the band gap value to 3.5 eV. However, in all other combination the systems show dispersed band at the Fermi level exhibiting conducting behavior. Moreover, from the analysis of band structure and Density Of States we can conclude that, the hydrogenation tunes the band gap of hexagonal boron nitride.

Influence of defect pairs in Ga-based ordered defect compounds: a hybrid density functional study

2020 ◽  
Vol 98 (8) ◽  
pp. 770-777
Author(s):  
Sudhir Kumar ◽  
Suman Joshi ◽  
Durgesh Kumar Sharma ◽  
Sushil Auluck
Keyword(s):  
Band Gap ◽  
Energy Band ◽  
Density Functional ◽  
Functional Study ◽  
Energy Band Gap ◽  
Functional Theory ◽  
Lattice Constants ◽  
Donor Acceptor ◽  
The Stability ◽  
Hybrid Density Functional

In the present paper, density functional theory (DFT) based calculations have been performed to predict the stability, electronic, and optical properties of Ga-rich ordered defect compounds (ODCs). The calculated lattice constants, bulk modulus, their pressure derivatives, and optical constants show good agreement with available experimental data. The hybrid exchange correlations functional have been considered to calculate ground state total energy and energy band gap of the material. The calculated formation energy of ODCs comes smaller than pure CuGaSe2 (CGS). Our calculated optical absorption coefficients indicate that the energy band gap of ODCs can be tuned by changing the number of donor–acceptor defect pairs ([Formula: see text]). The band offset has been calculated to understand the reason of band gap alteration while the number of defect pair changes. Our results may be helpful for other experiments to further improve the performance of ODCs.

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