Band gap and electronic properties of wurtzite-structure ZnO co-doped with IIA and IIIA

Doping is an effective strategy to tune the electronic properties of semiconductors, but some side effects caused by mono-doping degrade the specific performance of matrixes. As a model system to minimize photoproduced electron-hole pairs recombination by anion–cation co-doping, we investigate the electronic structures and optical properties of (Fe[Formula: see text]+[Formula: see text]N) co-doped Cu2O using the first-principles calculations. Compared to the case of mono-doping, the Fe[Formula: see text]N[Formula: see text] (a Fe (N) atom substituting a Cu (O) atom) co-doping reduces the energy cost of doping as a consequence of the charge compensation between the iron and nitrogen impurities, which eliminates the isolated levels (induced by mono-dopant) in the band gap. Interestingly, it is found that the contributions of different host atoms (Cu and O) away from anion (N) and cation (Fe) dopants to the variation of near band gap electronic structure of the co-doped Cu2O are different. Moreover, co-doping reduces the band gap and increases the visible-light absorption of Cu2O. Both band gap reduction and low recombination rate are critical elements for efficient light-to-current conversion in co-doped semiconductor photocatalysts. These findings raise the prospect of using co-doped Cu2O with specifically engineered electronic properties in a variety of solar applications.

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Structural properties of GaAs/InGaAs/GaAs (001) and InGaAs/GaAs (001) heterostructures and correlation with electronic properties

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176149 ◽

1990 ◽

Vol 48 (4) ◽

pp. 602-603

Author(s):

J.M. Bonar ◽

R. Hull ◽

R. Malik ◽

R. Ryan ◽

J.F. Walker

Keyword(s):

Band Gap ◽

Electronic Properties ◽

Gaas Substrate ◽

Critical Thickness ◽

Lattice Mismatch ◽

Band Offset ◽

Misfit Dislocations ◽

Gaas Substrates ◽

Gaas Structure ◽

Low X

In this study we have examined a series of strained heteropeitaxial GaAs/InGaAs/GaAs and InGaAs/GaAs structures, both on (001) GaAs substrates. These heterostructures are potentially very interesting from a device standpoint because of improved band gap properties (InAs has a much smaller band gap than GaAs so there is a large band offset at the InGaAs/GaAs interface), and because of the much higher mobility of InAs. However, there is a 7.2% lattice mismatch between InAs and GaAs, so an InxGa1-xAs layer in a GaAs structure with even relatively low x will have a large amount of strain, and misfit dislocations are expected to form above some critical thickness. We attempt here to correlate the effect of misfit dislocations on the electronic properties of this material.The samples we examined consisted of 200Å InxGa1-xAs layered in a hetero-junction bipolar transistor (HBT) structure (InxGa1-xAs on top of a (001) GaAs buffer, followed by more GaAs, then a layer of AlGaAs and a GaAs cap), and a series consisting of a 200Å layer of InxGa1-xAs on a (001) GaAs substrate.

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Electronic, Structural, and Optical Structure of Mono-Doped and Co-Doped (210) TiO2 Brookite Surfaces for Application in Dye-Sensitized Solar Cells—A First Principles Study

Materials ◽

10.3390/ma14143918 ◽

2021 ◽

Vol 14 (14) ◽

pp. 3918

Author(s):

Ratshilumela S. Dima ◽

Lutendo Phuthu ◽

Nnditshedzeni E. Maluta ◽

Joseph K. Kirui ◽

Rapela R. Maphanga

Keyword(s):

Solar Cells ◽

Band Gap ◽

Dye Sensitized Solar Cells ◽

Visible Region ◽

Electromagnetic Spectrum ◽

Doped Tio2 ◽

Dye Sensitized ◽

Sensitized Solar Cells ◽

Co Doped ◽

Optical Structure

Titanium dioxide (TiO2) polymorphs have recently gained a lot of attention in dye-sensitized solar cells (DSSCs). The brookite polymorph, among other TiO2 polymorphs, is now becoming the focus of research in DSSC applications, despite the difficulties in obtaining it as a pure phase experimentally. The current theoretical study used different nonmetals (C, S and N) and (C-S, C-N and S-N) as dopants and co-dopants, respectively, to investigate the effects of mono-doping and co-doping on the electronic, structural, and optical structure properties of (210) TiO2 brookite surfaces, which is the most exposed surface of brookite. The results show that due to the narrowing of the band gap and the presence of impurity levels in the band gap, all mono-doped and co-doped TiO2 brookite (210) surfaces exhibit some redshift. In particular, the C-doped, and C-N co-doped TiO2 brookite (210) surfaces exhibit better absorption in the visible region of the electromagnetic spectrum in comparison to the pure, S-doped, N-doped, C-S co-doped and N-S co-doped TiO2 brookite (210) surfaces.

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Strain-induced semimetal-to-semiconductor transition and indirect-to-direct band gap transition in monolayer 1T-TiS2

RSC Advances ◽

10.1039/c5ra16877e ◽

2015 ◽

Vol 5 (102) ◽

pp. 83876-83879 ◽

Cited By ~ 23

Author(s):

Chengyong Xu ◽

Paul A. Brown ◽

Kevin L. Shuford

Keyword(s):

Band Gap ◽

Electronic Properties ◽

Plane Strain ◽

Material Properties ◽

First Principles ◽

Tensile Strain ◽

First Principles Calculations ◽

Direct Band Gap ◽

Direct Band ◽

Uniform Plane

We have investigated the effect of uniform plane strain on the electronic properties of monolayer 1T-TiS2using first-principles calculations. With the appropriate tensile strain, the material properties can be transformed from a semimetal to a direct band gap semiconductor.

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Wide Band Gap Al and In Co-doped ZnO Films for Near-Infrared Plasmonic Application

Plasmonics ◽

10.1007/s11468-021-01434-5 ◽

2021 ◽

Author(s):

Soumya Kannoth ◽

Packia Selvam Irulappan ◽

Sandip Dhara ◽

Sankara Narayanan Potty

Keyword(s):

Band Gap ◽

Near Infrared ◽

Wide Band ◽

Zno Films ◽

Wide Band Gap ◽

Doped Zno ◽

Co Doped

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Band gap engineering of Gd and Co doped BiFeO3 and their application in hydrogen production through photoelectrochemical route

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2017.07.153 ◽

2017 ◽

Vol 42 (36) ◽

pp. 22677-22686 ◽

Cited By ~ 27

Author(s):

Alok K. Vishwakarma ◽

Prashant Tripathi ◽

Amit Srivastava ◽

A.S.K. Sinha ◽

O.N. Srivastava

Keyword(s):

Hydrogen Production ◽

Band Gap ◽

Band Gap Engineering ◽

Co Doped

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First-Principles Study on the Stabilities, Electronic and Optical Properties of GexSn1-xSe Alloys

Nanomaterials ◽

10.3390/nano8110876 ◽

2018 ◽

Vol 8 (11) ◽

pp. 876 ◽

Cited By ~ 1

Author(s):

Qi Qian ◽

Lei Peng ◽

Yu Cui ◽

Liping Sun ◽

Jinyan Du ◽

...

Keyword(s):

Optical Properties ◽

Solar Cells ◽

Band Gap ◽

Electronic Properties ◽

First Principles ◽

Future Application ◽

First Principles Calculations ◽

Electronic And Optical Properties ◽

Direct Bandgap ◽

The Future

We systematically study, by using first-principles calculations, stabilities, electronic properties, and optical properties of GexSn1-xSe alloy made of SnSe and GeSe monolayers with different Ge concentrations x = 0.0, 0.25, 0.5, 0.75, and 1.0. Our results show that the critical solubility temperature of the alloy is around 580 K. With the increase of Ge concentration, band gap of the alloy increases nonlinearly and ranges from 0.92 to 1.13 eV at the PBE level and 1.39 to 1.59 eV at the HSE06 level. When the Ge concentration x is more than 0.5, the alloy changes into a direct bandgap semiconductor; the band gap ranges from 1.06 to 1.13 eV at the PBE level and 1.50 to 1.59 eV at the HSE06 level, which falls within the range of the optimum band gap for solar cells. Further optical calculations verify that, through alloying, the optical properties can be improved by subtle controlling the compositions. Since GexSn1-xSe alloys with different compositions have been successfully fabricated in experiments, we hope these insights will contribute to the future application in optoelectronics.

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CHANGES INDUCED IN THE SURFACE ELECTRONIC STRUCTURE OF Be(0001) AFTER Si ADSORPTION

Surface Review and Letters ◽

10.1142/s0218625x02002907 ◽

2002 ◽

Vol 09 (02) ◽

pp. 687-691

Author(s):

L. I. JOHANSSON ◽

C. VIROJANADARA ◽

T. BALASUBRAMANIAN

Keyword(s):

Electronic Structure ◽

Band Structure ◽

Band Gap ◽

Electronic Properties ◽

Surface State ◽

Core Level ◽

Clean Surface ◽

Core Level Spectrum ◽

Surface Band ◽

Surface Electronic Structure

A study of effects induced in the Be 1s core level spectrum and in the surface band structure after Si adsorption on Be(0001) is reported. The changes in the Be 1s spectrum are quite dramatic. The number of resolvable surface components and the magnitude of the shifts do decrease and the relative intensities of the shifted components are drastically different compared to the clean surface. The surface band structure is also strongly affected after Si adsorption and annealing. At [Formula: see text] the surface state is found to move down from 2.8 to 4.1 eV. The band also splits at around 0.5 Å-1 along both the [Formula: see text] and [Formula: see text] directions. At [Formula: see text] and beyond [Formula: see text] only one surface state is observed in the band gap instead of the two for the clean surface. Our findings indicate that a fairly small amount of Si in the outer atomic layers strongly modifies the electronic properties of these layers.

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Hydration Dependent Band Gap Tunability of Self-Assembled Phenylalanine-Tryptophan Nanotubes

10.26434/chemrxiv.12720695 ◽

2020 ◽

Author(s):

Hugo Souza ◽

Antonio Chaves Neto ◽

Francisco Sousa ◽

Rodrigo Amorim ◽

Alexandre Reily Rocha ◽

...

Keyword(s):

Density Functional Theory ◽

Band Gap ◽

Electronic Properties ◽

Building Block ◽

Density Functional ◽

Tight Binding ◽

Water Molecules ◽

Confined Water ◽

Functional Theory ◽

Tight Binding Method

In this work, we investigate the effects of building block separation of Phenylalanine-Tryptophan nanotube induced by the confined water molecules on the electronic properties using density-functional theory based tight-binding method. <div><br></div>

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Band gap and morphology engineering of TiO2 by silica and fluorine co-doping for efficient ultraviolet and visible photocatalysis

RSC Advances ◽

10.1039/c6ra06410h ◽

2016 ◽

Vol 6 (68) ◽

pp. 63117-63130 ◽

Cited By ~ 21

Author(s):

Hua Tang ◽

Shufang Chang ◽

Kongqiang Wu ◽

Guogang Tang ◽

Yanhui Fu ◽

...

Keyword(s):

Photocatalytic Activity ◽

Band Gap ◽

Synthetic Method ◽

Co Doping ◽

Morphology Engineering ◽

Visible Photocatalysis ◽

Co Doped

Silicon and fluorine co-doped anatase TiO2 (Si–F–TiO2) photocatalysts with enhanced photocatalytic activity were successfully prepared via a facile two-step synthetic method by using SiO2 powders and (NH4)2TiF6 as the precursors.

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