scholarly journals Stable GaSe-Like Phosphorus Carbide Monolayer with Tunable Electronic and Optical Properties from Ab Initio Calculations

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1937 ◽  
Author(s):  
Xiaolin Cai ◽  
Zhili Zhu ◽  
Weiyang Yu ◽  
Chunyao Niu ◽  
Jianjun Wang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Electronic Structures ◽  
Density Functional ◽  
Promising Candidate ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Direct Band Gap ◽  
Direct Band ◽  
Indirect Band Gap

On the basis of density functional theory (DFT) calculations, we propose a stable two-dimensional (2D) monolayer phosphorus carbide (PC) with a GaSe-like structure, which has intriguing electronic and optical properties. Our calculated results show that this 2D monolayer structure is more stable than the other allotropes predicted by Tománek et al. [Nano Lett., 2016, 16, 3247–3252]. More importantly, this structure exhibits superb optical absorption, which can be mainly attributed to its direct band gap of 2.65 eV. The band edge alignments indicate that the 2D PC monolayer structure can be a promising candidate for photocatalytic water splitting. Furthermore, we found that strain is an effective method used to tune the electronic structures varying from direct to indirect band-gap semiconductor or even to metal. In addition, the introduction of one carbon vacancy in such a 2D PC structure can induce a magnetic moment of 1.22 µB. Our findings add a new member to the 2D material family and provide a promising candidate for optoelectronic devices in the future.

Electronic structures and optical properties of IV A elements-doped 3C-SiC from density functional calculations

2018 ◽  
Vol 32 (32) ◽  
pp. 1850389 ◽  
Author(s):  
Xuefeng Lu ◽  
Tingting Zhao ◽  
Xin Guo ◽  
Meng Chen ◽  
Junqiang Ren ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Electronic Structures ◽  
Density Functional ◽  
Visible Region ◽  
First Principles Calculation ◽  
Charge Difference Density ◽  
Direct Band ◽  
Density Analysis ◽  
Indirect Band Gap

Electronic structures and optical properties of IV A elements (Ge, Sn and Pb)-doped 3C-SiC are investigated by means of the first-principles calculation. The results reveal that the structure of Ge-doped system is more stable with a lower formation energy of 1.249 eV compared with those of Sn- and Pb-doped 3C-SiC systems of 3.360 eV and 5.476 eV, respectively. Doping of the IV A elements can increase the band gap, and there is an obvious transition from an indirect band gap to a direct band gap. Furthermore, charge difference density analysis proves that the covalent order of bonding between the doping atoms and the C atoms is Ge–C [Formula: see text] Sn–C [Formula: see text] Pb–C, which is fully verified by population values. Due to the lower static dielectric constant, the service life of 3C-SiC dramatically improved in production practice. Moreover, the lower reflectivity and absorption peak in the visible region, implying its wide application foreground in photoelectric devices.

scholarly journals Strain and Electric Field Modulated Indirect to Direct Band Transition of Monolayer GaInS2

2021 ◽  
Author(s):  
Atanu Betal ◽  
Jayanta Bera ◽  
Satyajit Sahu
Keyword(s):  
Optical Properties ◽  
Electric Field ◽  
Band Gap ◽  
Density Functional ◽  
Compressive Strain ◽  
Direct Band Gap ◽  
Td Dft ◽  
Direct Band ◽  
Band Transition ◽  
Indirect Band Gap

Abstract Strain and electric field dependent electronic and optical properties have been calculated using density functional theory (DFT) and time-dependent DFT (TD-DFT) for GaInS2 monolayer. GaInS2 monolayer shows an indirect band gap of 1.79 eV where valance band maxima (VBM) and conduction band maxima (CBM) rest between K and Γ point and at Γ point, respectively. Under a particular tensile strain (8%), a phase change from semiconductor to semimetal has been noticed. While at 4% compressive strain, the material changes from indirect to direct band gap of 2.22 eV having VBM and CBM at Γ point. With further increase in compressive strain, CBM shifted from Γ to M point, which leads to an indirect band gap again. The electric field also affects the band structure of monolayer GaInS2 and shows the transition between indirect to direct band gap at positive electric field of 4 V/nm, which acts normal to the surface. The strain-dependent optical properties are also calculated, which suggests that the absorption coefficient increases with compressive strain.

Indirect-Direct Band Gap Transition by Van Der Waals Interaction Engineering in MoS2/WS2 Bilayer Heterojunction

2014 ◽  
Vol 614 ◽  
pp. 70-74 ◽  
Author(s):  
Hai Ning Cao ◽  
Zhi Ya Zhang ◽  
Ming Su Si ◽  
Feng Zhang ◽  
Yu Hua Wang
Keyword(s):  
Band Gap ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Direct Band Gap ◽  
The Density Functional Theory ◽  
Direct Band ◽  
Electric Filed

First principles calculations based on the density functional theory (DFT) are employed to estimate the electronic structures of bilayer heterostructure of MoS2/WS2. The dependences of the band structures on external electric field and interlayer separation are evaluated. The external electric filed induces a semiconductor-metal transition. At the same time, a larger interlayer separation, corresponding to a weaker interlayer interaction, makes an indirect-direct band gap transition happen for the heterojunction. Our results demonstrate that electronic structure tailoring of two-dimensional layered materials should include both spatial symmetry control and interlayer vdW interactions engineering.

scholarly journals Band gap tuning from an indirect EuGa2S4 to a direct EuZnGeS4 semiconductor: syntheses, crystal and electronic structures, and optical properties

RSC Advances ◽  
2017 ◽  
Vol 7 (9) ◽  
pp. 5039-5045 ◽  
Author(s):  
Yang Chi ◽  
Sheng-Ping Guo ◽  
Huai-Guo Xue
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Electronic Structures ◽  
Direct Band Gap ◽  
Simple Substitution ◽  
Direct Band ◽  
Indirect Band Gap ◽  
Band Gap Tuning

Novel EuZnGeS4, with a direct band gap, can be obtained via simple substitution from EuGa2S4, with an indirect band gap.

STRUCTURAL PARAMETERS AND OPTOELECTRONIC PROPERTIES OF Mg-IV-V2 (IV=Si, Ge, Sn AND V=P, As) COMPOUNDS

2018 ◽  
Vol 25 (05) ◽  
pp. 1850108 ◽  
Author(s):  
M. IBRAHIM ◽  
HAYAT ULLAH ◽  
SAEED ULLAH JAN ◽  
MANZAR ALI ◽  
M. GULBAHAR ASHIQ
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Density Functional ◽  
Structural Parameters ◽  
Visible Region ◽  
Functional Theory ◽  
Lattice Constants ◽  
Direct Band Gap ◽  
Semiconductor Behavior ◽  
Direct Band

Semiconductors are the backbone of the optoelectronic industry. Direct band gap materials in the visible energy region are highly desirable for the efficient optoelectronic applications. In this work, we have probed the structural, electronic and optical properties of Mg-IV-V2 (IV[Formula: see text]Si, Ge, Sn and V[Formula: see text]P, As) compounds by FP-LAPW calculations, based on density functional theory. Their crystal structure is chalcopyrite with space group of I-42d. The lattice constants of MgSiP2, MgSiAs2 and MgGeAs2 are consistent with experimental results. These compounds show semiconductor behavior with direct band gap ranging from 1.3–2.15[Formula: see text]eV. Optical properties were also investigated. Optical properties include real and imaginary parts of dielectric constant, energy loss function, refraction and reflection. Direct band gap nature and good response in the visible region of these compounds predict their usefulness in optoelectronic devices.

Electronic and optical properties of Janus Monolayers MoXB2(X=S,Se): First-principles prediction

2021 ◽  
Author(s):  
Qingwen Lan ◽  
Changpeng Chen ◽  
Tian Qin
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
First Principles ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
Direct Band Gap ◽  
Direct Band ◽  
Indirect Band Gap ◽  
The Stability ◽  
Optical Calculation

By means of comprehensive first-principles calculations, we studied the geometric structure, the stability and electronic properties of the new two-dimensional(2D) Janus MoXB2(X=S, Se) monolayers. Our calculations demonstrated that the predicted Janus MoXB2 monolayers are all stable semiconductors with direct band gap. In this paper, we focus on impacts upon the electronic and optical properties of the MoXB2 monolayers under the different biaxial strains. With the compressive stress increases, the MoXB2 monolayers would become indirect band gap semiconductors, and then behave as semimetal. While under tensile strain, MoXB2 still maintain direct band gap. In addition, the optical calculation shows that biaxial strain leads to blue shifts in the optical absorption and reflectivity. The result indicates that MoXB2 may be promised nano candidate materials in optoelectronic devices.

scholarly journals First Principles Study of Electronic and Optical Properties of Pristine and X (Cu, Ag And Au) Doped BiOBr

2018 ◽  
Vol 22 (2) ◽  
pp. 63-69 ◽  
Author(s):  
Samir Paudel ◽  
Puspa Raj Adhikari ◽  
Om Prakash Upadhyay ◽  
Gopi Chandra Kaphle ◽  
Anurag Srivastava
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Ab Initio Approach ◽  
Indirect Band Gap ◽  
Standard Density

The electronic structures and optical properties of pristine BiOBr and Cu, Ag and Au doped BiOBr have been analyzed by using a standard density functional theory based ab-initio approach employing generalized gradient approximation through revised Perdew Burke Ernzerhoff type parameterization. The calculation shows that both the doped and pristine BiOBr have indirect band gap, the band gap of the pristine BiOBr found 2.22eV, whereas band gap significantly reduced after doping Cu, Ag and Au on BiOBr. The band gap of Cu, Ag and Au doped BiOBr are 1.2eV, 0.9eV and 1.76eV respectively. The optical properties have been studied through dielectric function, both pure and doped BiOBr shows anisotropic nature. Journal of Institute of Science and TechnologyVolume 22, Issue 2, January 2018, page: 63-69 

Tunable electronic properties of GaS-SnS2 heterostructure by strain and electric field

2021 ◽  
Author(s):  
Dahua Ren ◽  
Qiang Li ◽  
Kai Qian ◽  
Xingyi Tan
Keyword(s):  
Optical Properties ◽  
Electric Field ◽  
Visible Light ◽  
Electronic Properties ◽  
Electronic Structures ◽  
Density Functional ◽  
Band Alignment ◽  
Promising Candidate ◽  
Functional Theory ◽  
External Strain

Abstract Vertically stacked heterostructures have received extensive attention because of their tunable electronic structures and outstanding optical properties. In this work, we have studied the structural, electronic and optical properties of vertically stacked GaS-SnS2 heterostructure under the frame of density functional theory. We find that the stacked GaS-SnS2 heterostructure is a semiconductor with suitable indirect band gaps of 1.82 eV, exhibiting a type-II band alignment for easily separating the photo-generated carriers. The electronic properties of GaS-SnS2 heterostructure can be effectively tuned by external strain and electric field. The optical absorption of GaS-SnS2 heterostructure is more enhanced by comparison with the GaS monolayer and SnS2 monolayer in the visible light. Our results suggest that GaS-SnS2 heterostructure is a promising candidate for the photocatalyst and photoelectronic devices in visible light.

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