scholarly journals Optical properties of semiconductor “anisotropic” quantum dot

2021 ◽  
Vol 22 (4) ◽  
pp. 786-791
Author(s):  
B.A. Lukiyanets ◽  
D.V. Matulka
Keyword(s):  
Optical Properties ◽  
Electromagnetic Wave ◽  
Optical Transitions ◽  
Effective Masses ◽  
Effective Factor ◽  
Degree Of Anisotropy ◽  
Nanoscale Object ◽  
Different Shapes ◽  
Polarization Of Light ◽  
Simultaneous Splitting

The optical properties of an “anisotropic” semiconductor nanodot – a nanoscale object in the form of a rectangular parallelepiped - with sides a ≠  b ≠ c  are considered. Such dimensions are closely related to the values of the effective masses of the electron. The analysis of the spectral dependence of the absorption coefficient a(w)  under different degrees of "anisotropy" and under different polarizations of the electromagnetic wave is carried out. The cases of the most intense optical transitions, i.e. between electronic states separated by the Fermi level, are analyzed. The obtained results indicate that 1) a(w) is of line structure, and 2) the positions of the peaks of a(w) in identical optical transitions in the isotropic nanodot and in the “anisotropic” ones coincide qualitatively.  However, different masses in the “anisotropic” nanodot lead to a shift to the left or right of the peaks relative to identical peaks in the isotropic nanodot with simultaneous splitting of its degenerate peaks. Such shifts and their magnitudes are determined both by the degree of anisotropy (i.e. by the ratio between the effective masses), and by the polarization of light. It is pointed out that modern achievements in the creation of ordered semiconductor materials with nanoobjects of different shapes and sizes in nanostructures allows us to consider polarized electromagnetic wave as an effective factor in achieving the desired physical characteristics.

scholarly journals Structural and Optical properties of Be, Mg and Ca nanorods and nanodisks

2021 ◽  
Author(s):  
Alexandros G. Chronis ◽  
Fotios Michos ◽  
Christos S Garoufalis ◽  
Michael M. Sigalas
Keyword(s):  
Optical Properties ◽  
Structural And Optical Properties ◽  
Electronic And Optical Properties ◽  
Different Shapes ◽  
Stable Structures

Nanorods and nanodisks of Be, Mg, and Ca with different shapes and sizes have been theoretically studied. Stable structures have been identified and their electronic and optical properties have been...

Effects of alloying on the optical properties of organic–inorganic lead halide perovskite thin films

2016 ◽  
Vol 4 (33) ◽  
pp. 7775-7782 ◽  
Author(s):  
Paul F. Ndione ◽  
Zhen Li ◽  
Kai Zhu
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Spectroscopic Ellipsometry ◽  
Optical Constants ◽  
Optical Transitions ◽  
Inorganic Perovskite ◽  
Inorganic Lead ◽  
Halide Perovskite ◽  
Lead Halide

Spectroscopic ellipsometry analysis of optical transitions and optical constants in hybrid organic–inorganic perovskite alloys.

SYMMETRY AND ELECTRO-OPTICAL PROPERTIES OF NANOTUBES

2002 ◽  
Vol 01 (03n04) ◽  
pp. 313-325 ◽  
Author(s):  
M. DAMNJANOVIĆ ◽  
I. MILOŠEVIĆ ◽  
T. VUKOVIĆ ◽  
B. NIKOLIĆ ◽  
E. DOBARDŽIĆ
Keyword(s):  
Carbon Nanotubes ◽  
Optical Properties ◽  
Density Functional ◽  
Tight Binding ◽  
Optical Characteristics ◽  
Optical Transitions ◽  
Matrix Elements ◽  
Selection Rules ◽  
Single Wall Carbon ◽  
Quantum Numbers

The symmetry of single-wall carbon and inorganic tubes is reviewed. For the carbon nanotubes it is used to get the full set of quantum numbers, in the efficient precision (combined density functional and tight-binding methods) calculation of electronic bands and their complete assignation, to obtain the selection rules for optical transitions and the momenta matrix elements for the Bloch eigen-states. The optical characteristics are thoroughly found, and discussed.

scholarly journals First–Principles Investigation of the Structural, Elastic, Electronic, and Optical Properties of α– and β–SrZrS3: Implications for Photovoltaic Applications

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 978
Author(s):  
Henry Igwebuike Eya ◽  
Esidor Ntsoenzok ◽  
Nelson Y. Dzade
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Visible Region ◽  
Charge Carriers ◽  
Band Gaps ◽  
Strong Light ◽  
Electronic And Optical Properties ◽  
Optical Absorbance ◽  
Effective Masses

Transition metal perovskite chalcogenides are attractive solar absorber materials for renewable energy applications. Herein, we present the first–principles screened hybrid density functional theory analyses of the structural, elastic, electronic and optical properties of the two structure modifications of strontium zirconium sulfide (needle–like α–SrZrS3 and distorted β–SrZrS3 phases). Through the analysis of the predicted electronic structures, we show that both α– and β–SrZrS3 materials are direct band gaps absorbers, with calculated band gaps of 1.38, and 1.95 eV, respectively, in close agreement with estimates from diffuse–reflectance measurements. A strong light absorption in the visible region is predicted for the α– and β–SrZrS3, as reflected in their high optical absorbance (in the order of 105 cm−1), with the β–SrZrS3 phase showing stronger absorption than the α–SrZrS3 phase. We also report the first theoretical prediction of effective masses of photo-generated charge carriers in α– and β–SrZrS3 materials. Predicted small effective masses of holes and electrons at the valence, and conduction bands, respectively, point to high mobility (high conductivity) and low recombination rate of photo-generated charge carriers in α– and β–SrZrS3 materials, which are necessary for efficient photovoltaic conversion.

Determination and Critical Assessment of the Optical Properties of Common Substrate Materials Used in III-V Nitride Heterostructures with Vacuum Ultraviolet Spectroscopic Ellipsometry

2001 ◽  
Vol 693 ◽  
Author(s):  
N.V. Edwards ◽  
O.P.A. Lindquist ◽  
L.D. Madsen ◽  
S. Zollner ◽  
K. Järrehdahl ◽  
...  
Keyword(s):  
Optical Properties ◽  
Dielectric Function ◽  
Spectroscopic Ellipsometry ◽  
Optical Constants ◽  
Vacuum Ultraviolet ◽  
Critical Assessment ◽  
Optical Transitions ◽  
Common Substrate ◽  
Materials Used

AbstractAs a first step toward enabling the in-line metrology of III-V nitride heterostructure and materials, we present the optical constants of the two common substrate materials over an unprecendented spectral range. Vacuum Ultraviolet spectroscopic ellipsometry (VUVSE) was used to obtain the optical constants for Al2O3 and the ordinary and extra-ordinary component of the dielectric function for both 4H- and 6H-SiC. The results are discussed in the context of anisotropy, polytypism, bandstructure, optical transitions, and preparation/characterization of abrupt surfaces, where appropriate.

On the laws of polarization and double refraction in regularly crystal­lized bodies. By David Brewster, LL. D. F. R. S. and Edin. In a letter to the Right Hon. Sir Joseph Banks, Bart. G. C. B. P. R. S

1833 ◽  
Vol 2 ◽  
pp. 92-93
Keyword(s):  
Optical Properties ◽  
General Principle ◽  
General View ◽  
Double Refraction ◽  
Primitive Form ◽  
General Law ◽  
Combined Action ◽  
The Right ◽  
Polarization Of Light ◽  
High Degree

In the different inquiries which the author has already laid before this Society, his attention was often directed to the phenomena of regular crystals; but he only lately succeeded in reducing under a general principle all those complex appearances which result from the combined action of more than one axis of double refraction. In this paper Dr. Brewster gives a general view of the present state of our knowledge respecting the double refraction and polarization of light, and afterwards traces the steps which led him to the discovery of the general law. He began his researches by the examination of 165 crystals, in 145 of which he discovered the property of double refraction. In 80 he was able to ascertain whether they had one or more axes; and by examining the tints which they exhibited at va­rious angular distances from the axes, whence the forces emanate, he has been led to a general principle, which embraces all the phenomena and extends to the most complex as well as to the most simple de­velopment of the polarizing forces. This general principle, says Dr. Brewster, is in no respect an empyrical expression of the facts which it represents, nor is it supported by any empyrical data. Founded on the principles of mechanics, it is a law rigorously physical, by which we are enabled to calculate all the tints of the coloured rings, and all the phenomena of double refraction, with as much accuracy as we can compute the motions of the heavenly bodies. The faculty of depolarization, explained by the author in a former paper, has been considered as sufficient indication of two separate images; and upon this principle it has been stated that all crystals are doubly refractive whose primitive form is neither the cube nor the regular octohedron: but this is incorrect; for some of these crystals possess a doubly refracting structure in a high degree. Ad­mitting the statement, however, it could not have been used as a rule for determining whether a crystal refracts doubly or singly; for it is more difficult to detect the primitive form than to examine the optical properties. Tungstate of lime, for instance, would have been reckoned a crystal without double refraction, when Haüy believed its primitive form to be the cube, although it is highly doubly refractive.

Controllable optical transitions of amorphous Mg and Mg–Ni films via electrochemical methods

2015 ◽  
Vol 17 (20) ◽  
pp. 13340-13346 ◽  
Author(s):  
Jiameng Qiu ◽  
Feilong Wu ◽  
Xin Jin ◽  
Xinyuan Gu ◽  
Wenbin Cai ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electrochemical Methods ◽  
Optical Transitions ◽  
Application Field

The optical properties of amorphous Mg–Ni films are readily manipulated, which greatly expands the application field of Mg-based films.

Sign in / Sign up

Export Citation Format

Share Document