First-principles self-energy calculations of carrier-induced band-gap narrowing in silicon

1992 ◽  
Vol 45 (23) ◽  
pp. 13741-13744 ◽  
Author(s):  
A. Oschlies ◽  
R. W. Godby ◽  
R. J. Needs
Keyword(s):  
Band Gap ◽  
First Principles ◽  
Energy Calculations ◽  
Self Energy ◽  
Band Gap Narrowing

THE EFFECT OF HIGH N-DOPED ANATASE TiO2 ON THE BAND GAP NARROWING AND REDSHIFT BY FIRST-PRINCIPLES

2012 ◽  
Vol 26 (27) ◽  
pp. 1250179 ◽  
Author(s):  
QINGYU HOU ◽  
YONGJUN JIN ◽  
CHUN YING ◽  
ERJUN ZHAO ◽  
YUE ZHANG ◽  
...  
Keyword(s):  
Band Gap ◽  
First Principles ◽  
Formation Energy ◽  
Doping Concentration ◽  
Covalent Bond ◽  
Anatase Tio2 ◽  
Structure Population ◽  
Densities Of States ◽  
N Doping ◽  
Band Gap Narrowing

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.

A systematic study of LaAlO3 with variation of Nd doping, case of band gap tuning: A first principles method

2016 ◽  
Vol 30 (04) ◽  
pp. 1650028 ◽  
Author(s):  
Sandeep Chettri ◽  
D. P. Rai ◽  
A. Shankar ◽  
M. P. Ghimire ◽  
R. Khenata ◽  
...  
Keyword(s):  
Band Gap ◽  
First Principles ◽  
Magnetic Moments ◽  
Full Potential ◽  
Generalized Gradient ◽  
In Doping ◽  
Spin Polarized ◽  
Band Gap Narrowing ◽  
Linearized Augmented Plane Wave ◽  
Band Gap Tuning

In this paper, the structural, electronic and magnetic properties of Nd-doped rare earth aluminate, La[Formula: see text]Nd[Formula: see text]AlO3 ([Formula: see text] = 0%–100%) is studied using the first-principles full potential linearized augmented plane wave (FP-LAPW) method. The effects of partial Nd substitution for La in LaAlO3 are studied using supercell calculations. The electronic structure analysis indicates La[Formula: see text]Nd[Formula: see text]AlO3 to be a probable half metal within the spin polarized generalized gradient approximation (GGA). The direct and indirect band gaps are reported and were analyzed as a function of concentration of Nd doping on LaAlO3. The calculated magnetic moments in La[Formula: see text]Nd[Formula: see text]AlO3 were found to arise mainly from the Nd-[Formula: see text] electrons which manifest the magnetic nature of the system. The significant band gap narrowing with increase in doping concentration may find important applications in optoelectronic devices.

Modulation of Band Gaps of Codoping GaN: A First Principles Study

2011 ◽  
Vol 287-290 ◽  
pp. 306-312
Author(s):  
Jing Wang ◽  
Ru Zhi Wang ◽  
Li Chun Xu ◽  
Hui Yan
Keyword(s):  
Solar Energy ◽  
Energy Conversion ◽  
Band Gap ◽  
Light Absorption ◽  
First Principles ◽  
Solar Energy Conversion ◽  
Visible Spectral Region ◽  
Intermediate Band ◽  
Band Gap Narrowing ◽  
Immense Potential

To improve the solar energy conversion of GaN for photocatalytic, the band gap of GaN should be tailored to match with visible light absorption, we calculated that Cr/C codoping effectively narrows the band gap of GaN by using first-principles calculations. Cr/C codoping can split the band gap with the formation of an intermediate band. Positive defect pair binding energy indicates that the defect pairs are stable with respect to the isolate impurity in the sample. The band gap narrowing can be optimized to shift light absorption into the peak of the visible spectral region , which enable maximal utilization of sunlight and thus offer immense potential for applications in solar energy conversion.

First-principles calculations of many-body band-gap narrowing at an Al/GaAs(110) interface

1993 ◽  
Vol 70 (11) ◽  
pp. 1685-1688 ◽  
Author(s):  
J. P. A. Charlesworth ◽  
R. W. Godby ◽  
R. J. Needs
Keyword(s):  
Band Gap ◽  
First Principles ◽  
First Principles Calculations ◽  
Many Body ◽  
Band Gap Narrowing

GWself-energy calculations of carrier-induced band-gap narrowing inn-type silicon

1995 ◽  
Vol 51 (3) ◽  
pp. 1527-1535 ◽  
Author(s):  
A. Oschlies ◽  
R. W. Godby ◽  
R. J. Needs
Keyword(s):  
Band Gap ◽  
Energy Calculations ◽  
Type Silicon ◽  
Band Gap Narrowing

First-Principles Calculations on Pure and Ga-Doped Anatase TiO2

2010 ◽  
Vol 156-157 ◽  
pp. 1385-1388
Author(s):  
Rui Qing Xu ◽  
Lan Fang Yao ◽  
Lin Li ◽  
Shuo Wang ◽  
Lin Lin Tian ◽  
...  
Keyword(s):  
Band Gap ◽  
First Principles ◽  
Density Functional ◽  
Correlation Energy ◽  
Anatase Tio2 ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Band Gap Narrowing

First-principles calculations using the plane-wave pseudo-potential (PWPP) method based on the density functional theory (DFT) is employed to study the crystal structure, band gap, density of states of anatase TiO2 doped with gadolinium (Gd). The generalized gradient approximation (GGA) based on exchange-correlation energy optimization is employed to calculate them. The calculated results demonstrate that the mixing of gadolinium dopants induces states with original titanium 3d and oxygen 2p valence band attributes to the band gap narrowing. This can enhance the photocatalytic activity of anatase TiO2.

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