First-principles calculation of compensated (2N, W) codoping impacts on band gap engineering in anatase TiO2

Anatase TiO 2 supercells were studied by first-principles, in which one was undoped and another three were high N -doping. Partial densities of states, band structure, population and absorption spectrum were calculated. The calculated results indicated that in the condition of TiO 2-x N x (x = 0.0625, 0.125, 0.25), the higher the doping concentration is, the shorter will be the lattice parameters parallel to the direction of c-axis. The strength of covalent bond significantly varied. The formation energy increases at first, and then decreases. The doping models become less stable as N -doping concentration increases. Meanwhile, the narrower the band gap is, the more significant will be the redshift, which is in agreement with the experimental results.

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Band gap engineering of FeS2 under biaxial strain: a first principles study

Physical Chemistry Chemical Physics ◽

10.1039/c4cp03453h ◽

2014 ◽

Vol 16 (44) ◽

pp. 24466-24472 ◽

Cited By ~ 25

Author(s):

Pin Xiao ◽

Xiao-Li Fan ◽

Li-Min Liu ◽

Woon-Ming Lau

Keyword(s):

Band Gap ◽

First Principles ◽

Tensile Strain ◽

Biaxial Strain ◽

Band Gap Engineering ◽

First Principles Study ◽

Maximum Value

The band gap increases with increasing tensile strain to its maximum value at 6% strain and then decreases.

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Investigation of Electronic Structures of F-Doped TiO2 by First-Principles Calculation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.620-622.647 ◽

2009 ◽

Vol 620-622 ◽

pp. 647-650 ◽

Cited By ~ 3

Author(s):

Ying Cui ◽

Hao Du ◽

Li Shi Wen

Keyword(s):

Photocatalytic Activity ◽

First Principles ◽

Electronic Structures ◽

Lower Energy ◽

Anatase Tio2 ◽

First Principles Calculation ◽

Visible Light Region ◽

Doped Tio2 ◽

Light Region ◽

Calculation Results

F-doped TiO2 has exhibited superior photocatalytic activity. However, its electronic structures and photocatalysis mechanism are still unclear. In the present work, the structural optimization and electronic structure of F-doped anatase TiO2 have been investigated by means of the first-principles pseudopotential total energy method. It has been demonstrated that F doping would modify the valence band at the lower energy direction in the F-doped TiO2. Calculation results confirm that doping of fluorine would not shift the absorption edge into the visible light region. Instead, we attributed its photocatalytic activity to the enhancement of the oxidative power of F-doped TiO2.

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Band gap engineering of wurtzite and zinc-blende GaN/AlN superlattices from first principles

Journal of Applied Physics ◽

10.1063/1.3505752 ◽

2010 ◽

Vol 108 (10) ◽

pp. 103701 ◽

Cited By ~ 24

Author(s):

X. Y. Cui ◽

B. Delley ◽

C. Stampfl

Keyword(s):

Band Gap ◽

First Principles ◽

Band Gap Engineering ◽

Zinc Blende

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First Principles Investigation on the Structural, Electronic and Optical Properties of Amorphous Silica Glass

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.268.92 ◽

2017 ◽

Vol 268 ◽

pp. 92-96

Author(s):

R.M. Nor ◽

S.N.M. Halim ◽

Mohamad Fariz Mohamad Taib ◽

M. Kamil Abd-Rahman

Keyword(s):

Optical Properties ◽

Band Gap ◽

Electronic Properties ◽

Amorphous Silica ◽

First Principles ◽

Glass Structure ◽

Small Sample ◽

First Principles Calculation ◽

Electronic And Optical Properties ◽

Amorphous Quartz

The structural, electronic, and optical properties of an amorphous SiO2 (a-SiO2) model is investigated by using first-principles calculation. Most research works used beta-cristobalite glass structure as a reference to amorphous silica structure. However, only the electronic properties were been presented without any link towards the optical properties. Here, we demonstrate simultaneous electronic and optical properties, which closely matched to a-SiO2 properties by generating small sample of amorphous quartz glass. Using the Rietveld refinement, amorphous silica structure was generated and optimized using density functional theory in CASTEP computer code. A thorough analysis of the amorphous quartz structure obtained from different thermal treatment was carried out. The structure of amorphous silica was validated with previous theoretical and experimental works. It is shown that small sample of amorphous silica have similar structural, electronic and optical properties with a larger sample. The calculated optical and electronic properties from the a-SiO2 glass match closely to previous theoretical and experimental data from others. The a-SiO2 band gap of 5.853 eV is found to be smaller than the experimental value of ~9 eV. This is due to the underestimation and assumption made in DFT. However, the band gap value is in good agreement with the other theoretical works. Apart from the absorption edge at around 6.5 eV, the refractive index is 1.5 at 0eV. Therefore, this atomic structure can served as a reference model for future research works on amorphous structures.

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