scholarly journals Strain Effects on the Electronic and Optical Properties of Kesterite Cu2ZnGeX4 (X = S, Se): First-Principles Study

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2692
Author(s):  
Jawad El Hamdaou ◽  
Mohamed El-Yadri ◽  
Mohamed Farkous ◽  
Mohamed Kria ◽  
Maykel Courel ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Band Gap Energy ◽  
Applied Strain ◽  
Photovoltaic Devices ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Low Energies ◽  
Semiconductor Compounds

Following the chronological stages of calculations imposed by the WIEN2K code, we have performed a series of density functional theory calculations, from which we were able to study the effect of strain on the kesterite structures for two quaternary semiconductor compounds Cu2ZnGeS4 and Cu2ZnGeSe4. Remarkable changes were found in the electronic and optical properties of these two materials during the application of biaxial strain. Indeed, the band gap energy of both materials decreases from the equilibrium state, and the applied strain is more pronounced. The main optical features are also related to the applied strain. Notably, we found that the energies of the peaks present in the dielectric function spectra are slightly shifted towards low energies with strain, leading to significant refraction and extinction index responses. The obtained results can be used to reinforce the candidature of Cu2ZnGeX4(X = S, Se) in the field of photovoltaic devices.

Ab initio study of oxygen vacancy effects on electronic and optical properties of NiO

MRS Advances ◽  
2016 ◽  
Vol 1 (37) ◽  
pp. 2617-2622 ◽  
Author(s):  
John Petersen ◽  
Fidele Twagirayezu ◽  
Pablo D. Borges ◽  
Luisa Scolfaro ◽  
Wilhelmus Geerts
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Local Density ◽  
Optical Transition ◽  
Energy Levels ◽  
Density Functional Theory Calculations ◽  
Local Density Of States ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
O Vacancy

ABSTRACTDensity Functional Theory calculations of electronic and optical properties of NiO, with and without O vacancies, are the focus of this work. Two bands, one fully occupied and the other unoccupied, induced by an O vacancy, are found in the gap. These energy levels are identified and analyzed by means of a local density of states (LDOS) calculation, and notable crystal field splitting can be seen. The real and imaginary parts of the dielectric function are calculated, and an additional optical transition can be seen at lower energy, which can be attributed to the O vacancy induced state in the band gap.

scholarly journals Electronic and Optical Properties of Sodium Niobate: A Density Functional Theory Study

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Daniel Fritsch
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Lead Zirconate Titanate ◽  
Density Functional ◽  
Room Temperature ◽  
Structural Phase ◽  
Density Functional Theory Calculations ◽  
Sodium Niobate ◽  
Functional Theory ◽  
Electronic And Optical Properties

In recent years, much effort has been devoted to replace the most commonly used piezoelectric ceramic lead zirconate titanate Pb[ZrxTi1−x]O3 (PZT) with a suitable lead-free alternative for memory or piezoelectric applications. One possible alternative to PZT is sodium niobate as it exhibits electrical and mechanical properties that make it an interesting material for technological applications. The high-temperature simple cubic perovskite structure undergoes a series of structural phase transitions with decreasing temperature. However, particularly the phases at room temperature and below are not yet fully characterised and understood. Here, we perform density functional theory calculations for the possible phases at room temperature and below and report on the structural, electronic, and optical properties of the different phases in comparison to experimental findings.

SiGe/h-BN heterostructure with inspired electronic and optical properties: a first-principles study

2016 ◽  
Vol 4 (42) ◽  
pp. 10082-10089 ◽  
Author(s):  
Xianping Chen ◽  
Xiang Sun ◽  
D. G. Yang ◽  
Ruishen Meng ◽  
Chunjian Tan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
First Principles Study

The structure along with the electronic and optical properties of a SiGe/BN monolayer heterostructure were theoretically researched using density functional theory calculations.

Tunable electronic structure and enhanced optical properties in quasi-metallic hydrogenated/fluorinated SiC heterobilayer

2016 ◽  
Vol 4 (31) ◽  
pp. 7406-7414 ◽  
Author(s):  
Xianping Chen ◽  
Junke Jiang ◽  
Qiuhua Liang ◽  
Ruishen Meng ◽  
Chunjian Tan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Electronic Structure ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Electronic And Optical Properties

The electronic and optical properties of a hydrogenated/fluorinated SiC heterobilayer were systematically investigated by using density functional theory calculations.

Electronic and optical properties of two-dimensional heterostructures and heterojunctions between doped-graphene and C- and N-containing materials

2021 ◽  
Author(s):  
Asadollah Bafekry ◽  
Daniela Gogova ◽  
Mohamed M. Fadlallah ◽  
Nguyen V. Chuong ◽  
Mitra Ghergherehchi ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Density Functional ◽  
Van Der Waals ◽  
Density Functional Theory Calculations ◽  
Two Dimensional ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Doped Graphene ◽  
C And N

The electronic and optical properties of vertical heterostructures (HTSs) and lateral heterojunctions (HTJs) between (B,N)-codoped graphene (dop@Gr) and graphene (Gr), C3N, BC3 and h-BN monolayers are investigated using van der Waals density functional theory calculations.

Structural, Electronic and Optical Properties of SiC Quantum Dots

2012 ◽  
Vol 18-19 ◽  
pp. 77-87 ◽  
Author(s):  
Jian Guang Wang ◽  
Peter Kroll
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Density Functional ◽  
Tensile Strain ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Energy Gaps ◽  
Quantum Confinement Effects ◽  
Homo Lumo

We Perform Density Functional Theory Calculations of the Hydrogen-Passivated Topological Silicon Carbide Quantum Dots (QDs) and Investigate their Structural, Electronic and Optical Properties. We Study Clusters Constructed from 3C-Sic with up to 8 Topological Shells, Corresponding to Diameters up to 2.2 Nm, Terminated Homogeneously with either Si-H or C-H Bonds. All Qds Exhibit Tensile Strain (1-5 %) within the Cluster Core. the Larger the Cluster, the Smaller the Strain in the Interior, however. Tensile Strain Increases from the inside of the Cluster towards the outside, Reaches a Maximum at the Second Layer below the Surface, and Vanishes only for Bonds Involving Surface Si or C Atoms. Quantum-Confinement Effects Are Observed for the Energy Gaps and Optical Gaps of SiC QDs. Size Has a Major Impact on the Absorption Edge in Comparison to a Weak Effect on the Photon Energy of the Spectra Maxima. Our Calculations Show that Surface Termination Plays a Crucial Role and Strongly Affects Energy Gaps, Optical Gaps and Optical Spectra. Orbitals around the HOMO-LUMO Gap Predominantly Localize within the Core of the Cluster, with Significant Contributions by the Surface for Si-H Terminated Clusters only.

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