Band gap narrowing and dielectric constant enhancement of (NbxTa(1-x))2O5 by electrochemical nitrogen doping

2018 ◽  
Vol 265 ◽  
pp. 326-335 ◽  
Author(s):  
F. Di Franco ◽  
A. Zaffora ◽  
M. Santamaria
Keyword(s):  
Dielectric Constant ◽  
Band Gap ◽  
Nitrogen Doping ◽  
Band Gap Narrowing

Band gap narrowing of TiO2 by nitrogen doping in atmospheric microwave plasma

2005 ◽  
Vol 413 (4-6) ◽  
pp. 454-457 ◽  
Author(s):  
Yong Cheol Hong ◽  
Chan Uk Bang ◽  
Dong Hun Shin ◽  
Han Sup Uhm
Keyword(s):  
Band Gap ◽  
Nitrogen Doping ◽  
Microwave Plasma ◽  
Band Gap Narrowing

Band-Gap Narrowing of Titanium Dioxide by Nitrogen Doping

2001 ◽  
Vol 40 (Part 2, No. 6A) ◽  
pp. L561-L563 ◽  
Author(s):  
Takeshi Morikawa ◽  
Ryoji Asahi ◽  
Takeshi Ohwaki ◽  
Koyu Aoki ◽  
Yasunori Taga
Keyword(s):  
Titanium Dioxide ◽  
Band Gap ◽  
Nitrogen Doping ◽  
Band Gap Narrowing

scholarly journals Mechanisms of Visible Light Photocatalysis in N-Doped Anatase TiO2with Oxygen Vacancies from GGA+U Calculations

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Hsuan-Chung Wu ◽  
Yu-Siang Lin ◽  
Syuan-Wei Lin
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Density Functional ◽  
Nitrogen Doping ◽  
Formation Energy ◽  
Oxygen Vacancies ◽  
Energy Charge ◽  
Visible Light Photocatalysis ◽  
Donor States ◽  
Band Gap Narrowing

We have systematically studied the photocatalytic mechanisms of nitrogen doping in anatase TiO2using first-principles calculations based on density functional theory, employing HubbardU(8.47 eV) on-site correction. The impurity formation energy, charge density, and electronic structure properties of TiO2supercells containing substitutional nitrogen, interstitial nitrogen, or oxygen vacancies were evaluated to clarify the mechanisms under visible light. According to the formation energy, a substitutional N atom is better formed than an interstitial N atom, and the formation of an oxygen vacancy in N-doped TiO2is easier than that in pure TiO2. The calculated results have shown that a significant band gap narrowing may only occur in heavy nitrogen doping. With light nitrogen doping, the photocatalysis under visible light relies on N-isolated impurity states. Oxygen vacancies existence in N-doped TiO2can improve the photocatalysis in visible light because of a band gap narrowing and n-type donor states. These findings provide a reasonable explanation of the mechanisms of visible light photocatalysis in N-doped TiO2.

Band-gap narrowing and potential fluctuation in Si-doped GaN

1999 ◽  
Vol 74 (1) ◽  
pp. 102-104 ◽  
Author(s):  
In-Hwan Lee ◽  
J. J. Lee ◽  
P. Kung ◽  
F. J. Sanchez ◽  
M. Razeghi
Keyword(s):  
Band Gap ◽  
Potential Fluctuation ◽  
Si Doped ◽  
Band Gap Narrowing

scholarly journals Characteristics of Poly(vinyl Alcohol) (PVA) Based Composites Integrated with Green Synthesized Al3+-Metal Complex: Structural, Optical, and Localized Density of State Analysis

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1316
Author(s):  
Shujahadeen B. Aziz ◽  
Muaffaq M. Nofal ◽  
Hewa O. Ghareeb ◽  
Elham M. A. Dannoun ◽  
Sarkawt A. Hussen ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Metal Complex ◽  
Band Gap ◽  
Optical Band Gap ◽  
Complex Dielectric Constant ◽  
Poly Vinyl Alcohol ◽  
Optical Parameters ◽  
Dispersion Energy ◽  
Casting Technique

The influence of dispersing Al-metal complex on the optical properties of PVA was investigated using UV–visible spectroscopy. Polymer composite films with various Al3+-complex amounts in the PVA matrix were arranged by solution casting technique by means of distilled water as a widespread solvent. The formation of Al3+-metal complex was verified through Ultraviolet–visible (UV-Vis) and Fourier-transform infrared spectroscopy (FTIR) examinations. The addition of Al-complex into the polymer matrix led to the recovery of the optical parameters such as dielectric constant (εr and εi) and refractive index (n). The variations of real and imaginary parts of complex dielectric constant as a function of photon wavelength were studied to calculate localized charge density values (N/m*), high-frequency dielectric constant, relaxation time, optical mobility, optical resistivity, and plasma angular frequency (ωp) of electrons. In proportion with Al3+-complex content, the N/m* values were amplified from 3.68 × 1055 kg−1 m−3 to 109 × 1055 kg−1 m−3. The study of optical parameters may find applications within optical instrument manufacturing. The optical band gap was determined from Tauc’s equation, and the type of electronic transition was specified. A remarkable drop in the optical band gap was observed. The dispersion of static refractive index (no) of the prepared composites was analyzed using the theoretical Wemple–DiDomenico single oscillator model. The average oscillator energy (Eo) and oscillator dispersion energy (Ed) parameters were estimated.

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