scholarly journals Incorporation of Large Impurity Atoms into the Diamond Crystal Lattice: EPR of Split-Vacancy Defects in Diamond

Crystals ◽  
2017 ◽  
Vol 7 (8) ◽  
pp. 237 ◽  
Author(s):  
Vladimir Nadolinny ◽  
Andrey Komarovskikh ◽  
Yuri Palyanov
Keyword(s):  
Crystal Lattice ◽  
Diamond Crystal ◽  
Vacancy Defects ◽  
Impurity Atoms

scholarly journals Effect of Point Defects on Electronic Properties and Structure of Talc (001) Surface by First Principles

Minerals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 69
Author(s):  
Xindi Ma ◽  
Huicong Du ◽  
Ping Lan ◽  
Jianhua Chen ◽  
Lihong Lan
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Surface States ◽  
State Density ◽  
Functional Theory ◽  
Vacancy Defects ◽  
Impurity Atoms ◽  
Electron State Density ◽  
Calculation Results ◽  
Impurity Defects

The surface structure and electronic properties of Mg vacancy defects on talc (001) and impurity defects with Fe, Mn, Ni, Al, and Ca replacing Mg atoms were calculated by using density functional theory. The calculation results show that the order of impurity substitution energy is Mn < Ni < Al < Ca < Fe. This indicates that Fe impurity defects are most easily formed in talc crystals. The covalent bonding between Si atoms and reactive oxygen atoms adjacent to impurity atoms is weakened and the ionic property is enhanced. The addition of Fe, Mn, and Ni atoms makes the surface of talc change from an insulator to a semiconductor and enhances its electrical conductivity. The analysis of electron state density shows that surface states composed of impurity atoms 4S orbital appear near the Fermi level.

Doping and Charging in Colloidal Semiconductor Nanocrystals

MRS Bulletin ◽  
2001 ◽  
Vol 26 (12) ◽  
pp. 1005-1008 ◽  
Author(s):  
Moonsub Shim ◽  
Congjun Wang ◽  
David J. Norris ◽  
Philippe Guyot-Sionnest
Keyword(s):  
Electrical Properties ◽  
Crystal Lattice ◽  
Electric Fields ◽  
Semiconductor Devices ◽  
Semiconductor Nanocrystals ◽  
Semiconductor Technology ◽  
Semiconductor Crystal ◽  
Impurity Atoms ◽  
Colloidal Semiconductor Nanocrystals ◽  
Colloidal Semiconductor

Modern semiconductor technology has been enabled by the ability to control the number of carriers (electrons and holes) that are available in the semiconductor crystal. This control has been achieved primarily with two methods: doping, which entails the introduction of impurity atoms that contribute additional carriers into the crystal lattice; and charging, which involves the use of applied electric fields to manipulate carrier densities near an interface or junction. By controlling the carriers with these methods, the electrical properties of the semiconductor can be precisely tailored for a particular application. Accordingly, doping and charging play a major role in most modern semiconductor devices.

scholarly journals Сравнительный анализ спектров люминесценции алмазов

2019 ◽  
Vol 127 (9) ◽  
pp. 507
Author(s):  
С.И. Зиенко ◽  
Д.С. Слабковский
Keyword(s):  
Comparative Analysis ◽  
Crystal Lattice ◽  
Diamond Crystal ◽  
Relaxation Frequency ◽  
Luminescence Spectra ◽  
Time Range ◽  
Energy Losses ◽  
Q Factor ◽  
Bandwidth Parameter ◽  
Resonant Radiation

AbstractTo identify the signs that distinguish natural diamonds from artificial diamonds, a comparative analysis of the luminescence spectra with regards to the Q factor, center of gravity, bandwidth parameter, and energy losses in the diamond crystal lattice under conditions of ohmic and dielectric relaxation of luminescence is performed. The phenomenon of resonant luminescence in the femtosecond time range is detected in diamond. It is established that natural and artificial diamonds noticeably differ in the relaxation frequency and in the energy of resonant radiation.

scholarly journals Formation of complexes consisting of impurity Mn atoms and group VI elements in the crystal lattice of silicon

2021 ◽  
Vol 24 (3) ◽  
pp. 255-260
Author(s):  
K.А. Ismailov ◽  
◽  
X.M. Iliev ◽  
M.O. Tursunov ◽  
B.K. Ismaylov ◽  
...  
Keyword(s):  
Complex Formation ◽  
Crystal Lattice ◽  
Silicon Crystal ◽  
Covalent Bond ◽  
Group Vi ◽  
Impurity Atoms ◽  
Unit Cells ◽  
Formation Of Complexes

Formation of complexes of impurity Mn atoms with impurity atoms of group VI elements (S, Se, Te) in the silicon crystal lattice has been studied. It has been experimentally found that formation of electrically neutral molecules with an ionic-covalent bond between Mn atoms and group VI elements takes place, which possibly leads to formation of new Si2BVI++Mn binary unit cells in the silicon crystal lattice. It has been shown that in the samples Si<S, Mn>, Si<Se, Mn> and Si<Te, Mn>, an intense complex formation occurs at the temperatures 1100, 820 and 650°C, respectively.

Internal Structure of Diamond Nanocrystals by Modeling and PDF Analysis

2013 ◽  
Vol 1554 ◽  
Author(s):  
S. Stelmakh ◽  
W. Palosz ◽  
S. Gierlotka ◽  
K. Skrobas ◽  
B. Palosz
Keyword(s):  
Crystal Lattice ◽  
Inner Core ◽  
Diamond Crystal ◽  
Perfect Crystal ◽  
Density Waves ◽  
Atomistic Models ◽  
Pdf Analysis ◽  
Density Modulation ◽  
Modulated Waves ◽  
Grain Core

ABSTRACTThe structure of nanocrystalline diamond was approximated by spherical nanograins assuming that the grain core with a perfect crystal lattice is surrounded by a sequence of shells with (essentially) identical atomic architecture but with altered density. We call such a model a nanocrystal with density modulated waves. To examine the effect of density modulation present in nanograins, we built atomistic models of nanodiamond grains and compared the average values of inter-atomic distances calculated for the grains with density waves to those calculated for grains with the perfect, diamond crystal lattice. We show that the atomic structure of nanodiamond can be best described by a model where, between the inner core and the surface layer, three density waves with intermittent compressive and tensile strains exist. The sequence of the density waves is preserved in all examined nanodiamond samples without regard to chemical treatment and vacuum annealing (at up to 1200°C).

scholarly journals Effect of light elements impurity atoms on grain boundary diffusion in FCC metals: a molecular dynamics simulation

2020 ◽  
Vol 62 (12) ◽  
pp. 930-935
Author(s):  
G. M. Poletaev ◽  
I. V. Zorya ◽  
R. Yu. Rakitin ◽  
M. D. Starostenkov
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Crystal Lattice ◽  
Grain Boundaries ◽  
Free Volume ◽  
Misorientation Angle ◽  
Light Elements ◽  
Self Diffusion ◽  
Impurity Atoms ◽  
Metal Atoms

Effect of carbon and oxygen impurity atoms on diffusion along the tilt grain boundaries with <100> and <111> misorientation axis in metals with FCC lattice was studied by mean of molecular dynamics method. Ni, Ag, and Al were considered as metals. Interactions of metal atoms with each other were described by many-particle Clery-Rosato potentials constructed within the framework of tight binding model. To describe interactions of atoms of light elements impurities with metal atoms and atoms of impurities with each other, Morse pair potentials were used. According to obtained results, impurities in most cases lead to an increase in self-diffusion coefficient along the grain boundaries, which is caused by deformation of crystal lattice near the impurity atoms. Therefore, additional distortions and free volume are formed along the boundaries. It is more expressed for carbon impurities. Moreover, with an increase in concentration of carbon in the metal, an increase in coefficient of grain-boundary self-diffusion was observed first, and then a decrease followed. This behavior is explained by formation of aggregates of carbon atoms at grain boundary, which leads to partial blocking of the boundary. Oxygen atoms had smaller effect on diffusion along the grain boundaries, which is apparently explained by absence of a tendency to form aggregates and lesser deformation of crystal lattice around impurity. The greatest effect of impurities on self-diffusion along the grain boundaries among the examined metals was observed for nickel. Nickel has the smallest lattice parameter, impurity atoms deform its lattice around itself more than aluminum and silver, and therefore they create relatively more lattice distortions in it and additional free volume along the grain boundaries, which lead to an increase in diffusion permeability. Diffusion coefficients along the high-angle boundaries with misorientation angle of 30° turned out to be approximately two times higher than along low-angle boundaries with a misorientation angle of 7°. Diffusion along the <100> grain boundaries flowed more intensively than along the <111> boundaries.

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