scholarly journals Temperature effects on the energy bandgap and conductivity effective masses of charge carriers in lead telluride from first-principles calculations

2014 ◽  
Vol 116 (1) ◽  
pp. 013708 ◽  
Author(s):  
S. Venkatapathi ◽  
B. Dong ◽  
C. Hin
Keyword(s):  
First Principles ◽  
Temperature Effects ◽  
Lead Telluride ◽  
Charge Carriers ◽  
First Principles Calculations ◽  
Effective Masses ◽  
Energy Bandgap

scholarly journals First–Principles Investigation of the Structural, Elastic, Electronic, and Optical Properties of α– and β–SrZrS3: Implications for Photovoltaic Applications

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 978
Author(s):  
Henry Igwebuike Eya ◽  
Esidor Ntsoenzok ◽  
Nelson Y. Dzade
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Visible Region ◽  
Charge Carriers ◽  
Band Gaps ◽  
Strong Light ◽  
Electronic And Optical Properties ◽  
Optical Absorbance ◽  
Effective Masses

Transition metal perovskite chalcogenides are attractive solar absorber materials for renewable energy applications. Herein, we present the first–principles screened hybrid density functional theory analyses of the structural, elastic, electronic and optical properties of the two structure modifications of strontium zirconium sulfide (needle–like α–SrZrS3 and distorted β–SrZrS3 phases). Through the analysis of the predicted electronic structures, we show that both α– and β–SrZrS3 materials are direct band gaps absorbers, with calculated band gaps of 1.38, and 1.95 eV, respectively, in close agreement with estimates from diffuse–reflectance measurements. A strong light absorption in the visible region is predicted for the α– and β–SrZrS3, as reflected in their high optical absorbance (in the order of 105 cm−1), with the β–SrZrS3 phase showing stronger absorption than the α–SrZrS3 phase. We also report the first theoretical prediction of effective masses of photo-generated charge carriers in α– and β–SrZrS3 materials. Predicted small effective masses of holes and electrons at the valence, and conduction bands, respectively, point to high mobility (high conductivity) and low recombination rate of photo-generated charge carriers in α– and β–SrZrS3 materials, which are necessary for efficient photovoltaic conversion.

Electronic Structure, Effective Masses and Optical Properties of Monoclinic HfO2 from First-Principles Calculations

2011 ◽  
Vol 216 ◽  
pp. 341-344 ◽  
Author(s):  
Qi Jun Liu ◽  
Zheng Tang Liu ◽  
Li Ping Feng
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Band Structure ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Effective Masses ◽  
Indirect Band Gap ◽  
Calculated Equilibrium

Electronic structure, effective masses and optical properties of monoclinic HfO2were studied using the plane-wave ultrasoft pseudopotential technique based on the first-principles density-functional theory (DFT). The calculated equilibrium lattice parameters are in agreement with the previous works. From the band structure, the effective masses and optical properties are obtained. The calculated band structure shows that monoclinic HfO2has indirect band gap and all of the effective masses of electrons and holes are less than that of a free electron. The peaks position distributions of imaginary parts of the complex dielectric function have been explained according to the theory of crystal-field and molecular-orbital bonding.

Electronic structure and transport properties of ternary skutterudite: CoX3/2Y3/2

2009 ◽  
Vol 1166 ◽  
Author(s):  
Dmitri Volja ◽  
Marco Fornari ◽  
Boris Kozinsky ◽  
Nicola Marzari
Keyword(s):  
Electronic Structure ◽  
Transport Properties ◽  
Valence Band ◽  
Power Factor ◽  
First Principles ◽  
First Principles Calculations ◽  
Wannier Functions ◽  
Effective Masses ◽  
Fundamental Cause ◽  
Parabolic Dispersion

AbstractElectronic properties of ternary skutterudites AX3/2Y3/2 (A=Co, X=Ge, Sn and Y=S, Te) are investigated using first principles calculations to clarify recent experimental results. Band derivatives are computed accurately within an approach based on Maximally Localized Wannier Functions (MLWFs). Band structures exhibit larger effective masses compared to parental binary CoSb3. Our results also indicate a more parabolic dispersion near the top of the valence band and a multivalley character in both conduction and valence band. Despite the improved thermopower these skutterudites has relatively low power factor due to increased resistivity. The fundamental cause of such large resistivity seems to be associated with the ionicity of the bonding.

scholarly journals First-Principles Calculations of Angular and Strain Dependence on Effective Masses of Two-Dimensional Phosphorene Analogues (Monolayer α-Phase Group-IV Monochalcogenides MX)

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 639 ◽  
Author(s):  
Yuanfeng Xu ◽  
Ke Xu ◽  
Hao Zhang
Keyword(s):  
First Principles ◽  
Group Iv ◽  
Uniaxial Tensile ◽  
Anisotropy Ratio ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Orbital Contribution ◽  
Strain Dependence ◽  
Effective Masses ◽  
Black Phosphorene

Group IV monochalcogenides M X (M = Ge, Sn; X = S, Se)-semiconductor isostructure to black phosphorene-have recently emerged as promising two-dimensional materials for ultrathin-film photovoltaic applications owing to the fascinating electronic and optical properties. Herein, using first-principles calculations, we systematically investigate the orbital contribution electronic properties, angular and strain dependence on the carrier effective masses of monolayer M X . Based on analysis on the orbital-projected band structure, the VBMs are found to be dominantly contributed from the p z orbital of X atom, while the CBM is mainly dominated by p x or p y orbital of M atom. 2D SnS has the largest anisotropy ratio due to the lacking of s orbital contribution which increases the anisotropy. Moreover, the electron/hole effective masses along the x direction have the steeper tendency of increase under the uniaxial tensile strain compared to those along y direction.

Adsorption properties of chloroform molecule on graphene: Experimental and first-principles calculations

2017 ◽  
Vol 31 (35) ◽  
pp. 1750335
Author(s):  
Y. L. Tian ◽  
H. L. Hua ◽  
W. W. Yue ◽  
M. N. Chen ◽  
G. C. Hu ◽  
...  
Keyword(s):  
Band Gap ◽  
First Principles ◽  
Density Functional ◽  
Adsorption Properties ◽  
Experimental Results ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Graphene Surface ◽  
Effective Masses ◽  
The Density Functional Theory

Adsorption properties of chloroform molecule (CHCl3) on graphene surface are studied experimentally and theoretically. Based on the density functional theory (DFT) calculations, effects of different adsorption configurations and different adsorption distances on the system’s conductivity properties are discussed, and the comparisons with the experimental results are made. It is found that band gap appears when the adsorption distance is 1.0 Å, which is about 0.32 eV near the Fermi level. However, the band gap is nearly zero when the adsorption distance is increased to 1.5 Å, so the conductivity of the system will be increased with the increasing of the adsorption distances. The density of states, the adsorption energy and the effective masses are also calculated and the analyses are consistent with the experimental results. Our results reveal that graphene could be used to build sensors or as a catalyst for molecular adsorption.

Adsorption of methanol molecule on graphene: Experimental results and first-principles calculations

2018 ◽  
Vol 32 (09) ◽  
pp. 1850102 ◽  
Author(s):  
X. W. Zhao ◽  
Y. L. Tian ◽  
W. W. Yue ◽  
M. N. Chen ◽  
G. C. Hu ◽  
...  
Keyword(s):  
First Principles ◽  
Adsorption Properties ◽  
Experimental Results ◽  
Methanol Molecule ◽  
First Principles Calculations ◽  
Adsorption System ◽  
Geometrical Structures ◽  
Effective Masses ◽  
Wide Range ◽  
Adsorption Energies

Adsorption properties of methanol molecule on graphene surface are studied both theoretically and experimentally. The adsorption geometrical structures, adsorption energies, band structures, density of states and the effective masses are obtained by means of first-principles calculations. It is found that the electronic characteristics and conductivity of graphene are sensitive to the methanol molecule adsorption. After adsorption of methanol molecule, bandgap appears. With the increasing of the adsorption distance, the bandgap, adsorption energy and effective mass of the adsorption system decreased, hence the resistivity of the system decreases gradually, these results are consistent with the experimental results. All these calculations and experiments indicate that the graphene-based sensors have a wide range of applications in detecting particular molecules.

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