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.

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.

scholarly journals Properties of Novel Non-Silicon Materials for Photovoltaic Applications: A First-Principle Insight

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2006 ◽  
Author(s):  
Murugesan Rasukkannu ◽  
Dhayalan Velauthapillai ◽  
Federico Bianchini ◽  
Ponniah Vajeeston
Keyword(s):  
Band Gap ◽  
Density Functional ◽  
Crystalline Silicon ◽  
Visible Region ◽  
Initial Population ◽  
First Principle ◽  
Direct Band Gap ◽  
Depth Analysis ◽  
Photovoltaic Applications ◽  
Direct Band

Due to the low absorption coefficients of crystalline silicon-based solar cells, researchers have focused on non-silicon semiconductors with direct band gaps for the development of novel photovoltaic devices. In this study, we use density functional theory to model the electronic structure of a large database of candidates to identify materials with ideal properties for photovoltaic applications. The first screening is operated at the GGA level to select only materials with a sufficiently small direct band gap. We extracted twenty-seven candidates from an initial population of thousands, exhibiting GGA band gap in the range 0.5–1 eV. More accurate calculations using a hybrid functional were performed on this subset. Based on this, we present a detailed first-principle investigation of the four optimal compounds, namely, TlBiS2, Ba3BiN, Ag2BaS2, and ZrSO. The direct band gap of these materials is between 1.1 and 2.26 eV. In the visible region, the absorption peaks that appear in the optical spectra for these compounds indicate high absorption intensity. Furthermore, we have investigated the structural and mechanical stability of these compounds and calculated electron effective masses. Based on in-depth analysis, we have identified TlBiS2, Ba3BiN, Ag2BaS2, and ZrSO as very promising candidates for photovoltaic applications.

The effects of Sc doping and O vacancy on the electronic states and optical properties of m-BiVO4

2020 ◽  
Author(s):  
Yuhong Huang ◽  
Xiaqing Zhang ◽  
Jingnan Wang ◽  
Jianmin Zhang ◽  
Xiumei Wei ◽  
...  
Keyword(s):  
Optical Properties ◽  
Oxygen Vacancy ◽  
Band Gap ◽  
Density Functional ◽  
Electronic States ◽  
Dft Method ◽  
Defect Concentration ◽  
Direct Band Gap ◽  
Direct Band ◽  
The Ideal

Based on density functional theory (DFT), the effects of scandium (Sc) doping and oxygen vacancy (VO) on the electronic states and optical properties of BiVO4 are investigated. GGA+U method is adopt during the calculation of the electronic properties to compensate the limitation of DFT method. The ideal BiVO4 has a direct band gap of 2.400 eV, and if Bi in BiVO4 is substituted by Sc (sub Sc-Bi), the direct band gap will be reduced to 2.393 eV. However, if V is replaced by Sc (sub Sc-V) as well as that with oxygen vacancy induced (sub Sc-V+Vo), the band gap will become indirect one with values of 1.913 eV and 2.198 eV, respectively. The reduction capability is in the sequence of sub Sc-Bi > ideal > sub Sc-V+Vo > sub Sc-V, while the oxidation capability is in the order of ideal > sub Sc-Bi > sub Sc-V+Vo > sub Sc-V. The ε<sub>1</sub> (0) of the ideal, sub Sc-Bi, subSc-V and sub Sc-V+Vo defective BiVO4 is 8.290, 8.293, 12.791 and 8.285, respectively. The optical absorptions of ideal and sub Sc-Bi BiVO4 show anisotropy and they are nearly independent on the defect concentration. Sub Sc-V BiVO4 exhibits stronger absorption than the other three semiconductors. The absorptions of sub Sc-V+Vo BiVO4 vary obviously with the defect concentrations, where 3.906% defect concentration of BiVO4 has the strongest absorptions. The estimated optical band gaps are smaller than for ideal and defective BiVO4.

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.

Optoelectronic Analysis of CdGa2X4 (X= S, Se): A Promising Material for Solar Cells

2017 ◽  
Vol 900 ◽  
pp. 69-73 ◽  
Author(s):  
Pancham Kumar ◽  
Jagrati Sahariya ◽  
Amit Soni ◽  
K.C. Bhamu
Keyword(s):  
Solar Cell ◽  
Band Gap ◽  
Density Of States ◽  
Density Functional ◽  
Visible Spectrum ◽  
Full Potential ◽  
Functional Theory ◽  
Augmented Plane Wave ◽  
Direct Band Gap ◽  
Direct Band

In this paper, the optoelectronic nature of the CdGa2X4 (X = S, Se) solar cell materials are examined using full potential linear augmented plane wave (FP-LAPW) method as embodied in WIEN2K code. In present computation, we have used most suitable modified Backe-Johnson (mBJ) potential under the framework of density functional theory (DFT). The calculated electronic properties like energy band structure and density of states spectra show that these materials exhibit a direct band gap (Γ–Γ) result of 3.22 eV and 2.36 eV for CdGa2S4 and CdGa2Se4 compounds, respectively. Absorption spectra for CdGa2X4 (X = S, Se) compounds have been studied and it has been found that above the band gap, absorption are taking place and it covers wide visible spectrum energy range. On the basis of calculated band gap, density of states and absorption coefficient spectra, it is found that these compounds can be suitably applicable in optoelectronic devices such as solar cell. The evaluated properties pose well agreement with available experimental data.

Computational study of Cu2ZnSn(X1−xTex)4 (X = S, Se) for optoelectronic applications

2016 ◽  
Vol 30 (22) ◽  
pp. 1650137 ◽  
Author(s):  
Naeem Ullah ◽  
G. Murtaza ◽  
M. A. Iqbal ◽  
Asif Mahmood ◽  
R. Khenata
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Computational Study ◽  
Visible Region ◽  
Strong Response ◽  
Functional Theory ◽  
Lattice Constants ◽  
Minimization Procedure ◽  
First Time ◽  
Time Density

The [Formula: see text], [Formula: see text] and [Formula: see text] and their alloys have been frequently investigated experimentally owing to their suitable bandgap for the solar cell applications. For the first time, density functional theory is applied to explore the structural, electronic and optical properties of [Formula: see text] and [Formula: see text] [Formula: see text]. The energy minimization procedure reveals that the Kesterite phase is stable compared to the Stannite structure. Lattice constants of the compounds are in good agreement with the previous experimental results. The alloys have direct bandgaps which decrease by increasing the concentration of Te. The chemical bonding among the cations and anion is dominantly covalent. Electronic bandgap dependent optical properties like absorption coefficient and optical conductivity are studied in detail. The materials show strong response in the visible region of energy spectrum indicating the usefulness of these materials for optoelectronic devices.

scholarly journals Theoretical Calculations of Structural, Mechanical, Electronic And Optical Properties of Sn2S3 Under Pressure

2021 ◽  
Author(s):  
Baishu Chen ◽  
Wenxia Zhu ◽  
Chunxiang Wang ◽  
Chang Wang ◽  
Yuanzuo Li ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Density Functional ◽  
Mechanical Stability ◽  
Pressure Effect ◽  
Theoretical Calculations ◽  
Structural Parameters ◽  
Electronic And Optical Properties ◽  
Lattice Constants ◽  
The Density Functional Theory

Abstract The pressure effect on the structural, mechanical, electronic and optical properties of Sn2S3 in the pressure range of 0–35 GPa have been evaluated by means of the first-principles calculations based on the density-functional theory. The structural parameters of Sn2S3 at 0 GPa such as lattice constants and cell volumes are consistent with the previous theoretical and experiment reports. The mechanical properties about the elastic constants (Cij) and polycrystalline elastic modulus (B, G and E) under pressure are calculated for the first time. Furthermore, the results suggest that the Sn2S3 is predicted to be mechanically stable in the range of pressure from 0 to 35 GPa in the light of the mechanical stability conditions. The Sn2S3 is found to be ductile from the value of B/G. With the increasing of pressure, the ductility of Sn2S3 enhances monotonously. The pressure effect on the energy band gap and density of states of Sn2S3 is also discussed, which indicates that the pressure makes the band gap of Sn2S3 decreased. The optical properties of Sn2S3 are calculated in the range 0–35 eV, and the results show that the Sn2S3 under pressure has stronger visible light absorption in comparison with 0 GPa.

Structural, Electronic and Optical Properties of High (γ)-Li2BeSiO4: First-Principles Calculations

2011 ◽  
Vol 197-198 ◽  
pp. 567-570
Author(s):  
Qi Jun Liu ◽  
Zheng Tang Liu ◽  
Li Ping Feng ◽  
Hao Tian
Keyword(s):  
Optical Properties ◽  
Chemical Bonding ◽  
First Principles ◽  
Density Functional ◽  
Structural Parameters ◽  
Population Analysis ◽  
Functional Theory ◽  
Charge Densities ◽  
Bonding Properties ◽  
Direct Band

We have performed ab-initio total energy calculations using the plane-wave ultrasoft pseudopotential technique based on the first-principles density-functional theory (DFT) to study structural parameters, electronic structure, chemical bonding and optical properties of orthorhombic Li2BeSiO4. The calculated lattice parameters are in agreement with experimental data. The band structure shows a direct band gap. From the DOS analysis, charge densities and population analysis, electronic and chemical bonding properties have been studied. Furthermore, in order to understand the mechanism of optical transitions of orthorhombic Li2BeSiO4, the complex dielectric functions are calculated and analysed.

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