scholarly journals Interstitial Channels that Control Band Gaps and Effective Masses in Tetrahedrally Bonded Semiconductors

2014 ◽  
Vol 112 (13) ◽  
Author(s):  
Yu-ichiro Matsushita ◽  
Atsushi Oshiyama
Keyword(s):  
Band Gaps ◽  
Effective Masses ◽  
Tetrahedrally Bonded

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.

Electrons in a square lattice

2021 ◽  
pp. 352-362
Author(s):  
Geoffrey Brooker
Keyword(s):  
Periodic Potential ◽  
Band Gaps ◽  
Three Dimensions ◽  
Square Lattice ◽  
One Dimension ◽  
Two Dimensional ◽  
Effective Masses ◽  
Overlapping Bands

“Electrons in a square lattice” describes how a two-dimensional square lattice gives a helpful case intermediate between one dimension and the complication of three dimensions. The “empty lattice” divides up k-space into Brillouin zones in anticipation of a periodic potential whose period is given but whose magnitude is at this stage zero. A wooden model uses height to represent energy. Rearranging the model's pieces into the reduced-zone scheme displays how electrons can have surprising energy–wavevector relations, including overlapping bands, anisotropic effective masses, and indirect band gaps.

Improved tight-binding parameters of III-V semiconductor alloys and their application to type-II superlattices

2021 ◽  
Author(s):  
Akitaka Sawamura ◽  
Takashi Kato ◽  
Satofumi SOUMA
Keyword(s):  
Absorption Coefficient ◽  
Energy Levels ◽  
Tight Binding ◽  
Band Gaps ◽  
Type Ii ◽  
Binding Parameters ◽  
Semiconductor Alloys ◽  
Effective Masses ◽  
Type Ii Superlattices ◽  
Ternary Semiconductor

Abstract A simple tight-binding method for ternary semiconductor alloys is generalized to calculate the properties of the semiconductor alloys accurately. Specifically independently adjustable parameters, which represent compositional disorder, are incorporated in all the ternary tight-binding parameters. Energy levels and effective masses agree well with the reference values only by the proposed method. We have applied the method to calculate the band gaps and a spectrum of the absorption coefficient of (InAs)/(GaInSb) type-II superlattices. The calculated band-gaps agree well with the experimental ones and we could well reproduce the shape of the absorption coefficient spectrum calculated by an empirical pseudopotential scheme.

On the band gaps and effective masses of mono and dual doped monolayer graphene

2017 ◽  
Vol 137 ◽  
pp. 20-29 ◽  
Author(s):  
Pablo A. Denis ◽  
C. Pereyra Huelmo ◽  
Federico Iribarne
Keyword(s):  
Band Gaps ◽  
Monolayer Graphene ◽  
Effective Masses

Electronic structure of free-standing InP and InAs nanowires

2006 ◽  
Vol 21 (11) ◽  
pp. 2927-2935 ◽  
Author(s):  
B. Lassen ◽  
M. Willatzen ◽  
R. Melnik ◽  
L.C. Lew Yan Voon
Keyword(s):  
Electronic Structure ◽  
Electronic Properties ◽  
Experimental Work ◽  
Band Gaps ◽  
Free Standing ◽  
Effective Masses ◽  
Inas Nanowires ◽  
Spurious Solution ◽  
Solution Problem

An eight-band k·p theory that does not suffer from the spurious solution problem is demonstrated. It is applied to studying the electronic properties of InP and InAs free-standing nanowires. Band gaps and effective masses are reported as a function of size, shape, and orientation of the nanowires. We compare our results with experimental work and with other calculations.

scholarly journals Низкоразмерные структуры карбида кремния: аналитические оценки характеристик электронного спектра

2020 ◽  
Vol 54 (5) ◽  
pp. 446
Author(s):  
С.Ю. Давыдов
Keyword(s):  
Silicon Carbide ◽  
Electronic Structure ◽  
Function Method ◽  
Tight Binding ◽  
Band Gaps ◽  
Tight Binding Approximation ◽  
One Dimensional ◽  
Dielectric Substrates ◽  
Effective Masses ◽  
Analytical Expressions

Abstract Using the Green’s function method within the tight-binding approximation, the electronic structure of an infinite silicon-carbide sheet, and nanoribbons and one-dimensional chains cut from it, is considered. Analytical expressions for band gaps, electron effective masses and characteristic velocities are derived. The effect of metal and dielectric substrates on the band characteristics is discussed.

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