Optical properties of strongly excited direct band gap materials

1974 ◽  
Vol 22 (1) ◽  
pp. 11-38 ◽  
Author(s):  
R. Levy ◽  
J. B. Grun
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Direct Band Gap ◽  
Direct Band

scholarly journals Stimulated Emission and Optical Properties of Solid Solutions of Cu(In,Ga)Se2 Direct Band Gap Semiconductors

2018 ◽  
Vol 85 (2) ◽  
pp. 267-273
Author(s):  
I. E. Svitsiankou ◽  
V. N. Pavlovskii ◽  
E. V. Lutsenko ◽  
G. P. Yablonskii ◽  
A. V. Mudryi ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Solid Solutions ◽  
Stimulated Emission ◽  
Direct Band Gap ◽  
Direct Band

scholarly journals Indirect-to-direct band gap transition and optical properties of metal alloys of Cs2Te1−xTixI6: a theoretical study

RSC Advances ◽  
2020 ◽  
Vol 10 (60) ◽  
pp. 36734-36740
Author(s):  
Diwen Liu ◽  
Wenying Zha ◽  
Rusheng Yuan ◽  
Benyong Lou ◽  
Rongjian Sa
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Theoretical Study ◽  
Metal Alloys ◽  
Double Perovskites ◽  
Direct Band Gap ◽  
Photovoltaic Applications ◽  
Direct Band

In recent years, double perovskites have attracted considerable attention as potential candidates for photovoltaic applications.

SHIFT OF BAND GAP FROM DIRECT TO INDIRECT AND OPTICAL RESPONSE OF LiF UNDER PRESSURE

2013 ◽  
Vol 27 (09) ◽  
pp. 1350061 ◽  
Author(s):  
A. SAJID ◽  
G. MURTAZA ◽  
A. H. RESHAK
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Lithium Fluoride ◽  
Pressure Range ◽  
Pressure Effect ◽  
Indirect Transition ◽  
Direct Band Gap ◽  
Direct Band ◽  
Indirect Band Gap

We hereby are reporting the transition pressure at which lithium fluoride ( LiF ) compound transforms from direct band gap to indirect band gap insulator on the basis of FP-LAPW calculations. The fundamental band gap of LiF compound suffers direct to indirect transition at a pressure of 70 GPa. The study of the pressure effect on the optical properties e.g. dielectric function, reflectivity, refractive index and optical conductivity of LiF in the pressure between 0–100 GPa, shows that this pressure range is very critical for LiF compound as there are significant changes in the optical properties of this compound.

scholarly journals Nickel doping effect on the structural and optical properties of indium sulfide thin films by SILAR

2018 ◽  
Vol 16 (1) ◽  
pp. 757-762 ◽  
Author(s):  
Fatma Göde ◽  
Serdar Ünlü
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Doping Concentration ◽  
Indium Sulfide ◽  
Ni Doping ◽  
X Ray ◽  
Direct Band Gap ◽  
Direct Band ◽  
Ni Dopant

AbstractUndoped and nickel doped indium sulfide (In2S3:Ni) thin films have been deposited on indium tin oxide (ITO) coated glass substrates by successive ionic layer adsorption and reaction (SILAR) method. The doping concentration of Ni has been adjusted as 4%, 5% and 6% (in molar ratio of nickel ions to indium ions). The effects of Ni doping on the structural, morphological, compositional and optical properties of the In2S3 thin films are investigated. The x-ray diffraction patterns show that deposited film has cubic structure with amorphous nature of In2S3 and its crystallinity deteriorates with increasing doping concentration. The SEM measurements show that the surface morphology of the films is affected from the Ni incorporation. The direct band gap of the films decreases from 2.33 eV to 1.61 eV with increasing Ni dopant. Energy dispersive x-ray spectroscopy (EDS) has been used to evaluate the chemical composition and shown that S/(Ni+In) ratio in films decreases from 1.18 to 0.40 with Ni content. Optical properties of the films have been performed by a UV-Vis spectrophotometer. The direct band gap of the films decreases from 2.33 eV to 1.61 eV with increasing Ni dopant. Moreover, optical parameters of the films such as refractive index (𝑛), extinction coefficient (k), real (ε1) and imaginary (ε2) parts of dielectric constant have been determined by using absorbance and transmittance spectra. The investigations showed that the Ni doping has a significant effect on the physical properties of SILAR produced In2S3 thin films.

The effects of Sc doping and O vacancy on the electronic states and optical properties of m-BiVO4

2020 ◽  
Author(s):  
Yuhong Huang ◽  
Xiaqing Zhang ◽  
Jingnan Wang ◽  
Jianmin Zhang ◽  
Xiumei Wei ◽  
...  
Keyword(s):  
Optical Properties ◽  
Oxygen Vacancy ◽  
Band Gap ◽  
Density Functional ◽  
Electronic States ◽  
Dft Method ◽  
Defect Concentration ◽  
Direct Band Gap ◽  
Direct Band ◽  
The Ideal

Based on density functional theory (DFT), the effects of scandium (Sc) doping and oxygen vacancy (VO) on the electronic states and optical properties of BiVO4 are investigated. GGA+U method is adopt during the calculation of the electronic properties to compensate the limitation of DFT method. The ideal BiVO4 has a direct band gap of 2.400 eV, and if Bi in BiVO4 is substituted by Sc (sub Sc-Bi), the direct band gap will be reduced to 2.393 eV. However, if V is replaced by Sc (sub Sc-V) as well as that with oxygen vacancy induced (sub Sc-V+Vo), the band gap will become indirect one with values of 1.913 eV and 2.198 eV, respectively. The reduction capability is in the sequence of sub Sc-Bi > ideal > sub Sc-V+Vo > sub Sc-V, while the oxidation capability is in the order of ideal > sub Sc-Bi > sub Sc-V+Vo > sub Sc-V. The ε<sub>1</sub> (0) of the ideal, sub Sc-Bi, subSc-V and sub Sc-V+Vo defective BiVO4 is 8.290, 8.293, 12.791 and 8.285, respectively. The optical absorptions of ideal and sub Sc-Bi BiVO4 show anisotropy and they are nearly independent on the defect concentration. Sub Sc-V BiVO4 exhibits stronger absorption than the other three semiconductors. The absorptions of sub Sc-V+Vo BiVO4 vary obviously with the defect concentrations, where 3.906% defect concentration of BiVO4 has the strongest absorptions. The estimated optical band gaps are smaller than for ideal and defective BiVO4.

Towards from indirect to direct band gap and optical properties of XYP2 (X=Zn, Cd; Y=Si, Ge, Sn)

2014 ◽  
Vol 441 ◽  
pp. 94-99 ◽  
Author(s):  
Sibghat ullah ◽  
G. Murtaza ◽  
R. Khenata ◽  
A.H. Reshak ◽  
S.S. Hayat ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Direct Band Gap ◽  
Direct Band

Optical Properties of CuZn0.8Cd0.2SnS4 Quinternary Alloy Nanostructures

2015 ◽  
Author(s):  
A. S. Ibraheam ◽  
Y. Al-Douri ◽  
U. Hashim ◽  
Waleed K. Ahmed
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Spin Coating ◽  
Band Gap Energy ◽  
Direct Band Gap ◽  
Gap Energy ◽  
Coating Technique ◽  
Cu Content ◽  
Direct Band ◽  
Alloy Nanostructures

Cu2Zn0.8Cd0.2SnS4 quinternary alloy nanostructures were prepared with different copper (Cu) concentrations; 0.3, 0.5, 0.7 and 0.9 mol/L using the spin coating technique. The direct band gap energy of Cu2Zn0.8Cd0.2SnS4 quinternary alloy nanostructures is investigated to decrease as Cu increases. The transmittance value in the range 63–49% is depending on Cu content.

Sign in / Sign up

Export Citation Format

Share Document