Dimer-vacancy defects on Si(1 0 0): The role of nickel impurity

2020 ◽  
Vol 506 ◽  
pp. 144647
Author(s):  
M. Kuzmin ◽  
J.-P. Lehtiö ◽  
Z.J. Rad ◽  
J. Mäkelä ◽  
A. Lahti ◽  
...  
Keyword(s):  
Vacancy Defects

Stability of vacancy defects in MgO: The role of charge neutrality

1994 ◽  
Vol 50 (4) ◽  
pp. 2582-2592 ◽  
Author(s):  
Andrew Gibson ◽  
Roger Haydock ◽  
John P. LaFemina
Keyword(s):  
Charge Neutrality ◽  
Vacancy Defects

scholarly journals Role of chemical substitution in the photoluminescence properties of cerium samarium tungstates Ce(2-x)Smx (WO4)3 (0≤x≤0.3)

2020 ◽  
Vol 225 ◽  
pp. 01013
Author(s):  
K. Derraji ◽  
C. Favotto ◽  
J-C Valmalette ◽  
S. Villain ◽  
J-R. Gavarri ◽  
...  
Keyword(s):  
Solid Solution ◽  
Rietveld Analysis ◽  
Excitation Energies ◽  
Diffraction Profile ◽  
Vacancy Defects ◽  
X Ray ◽  
Cell Parameters ◽  
Structural Distortions ◽  
Ir Emission

In the general framework of the development of materials with tunable photoluminescence, a series of cerium samarium tungstates Ce(2-x)Smx(WO4)3 with x≤0.3 was synthesized by a coprecipitation method followed by thermal treatment at 1000 °C. The polycrystalline compounds were characterized by X-ray diffraction, scanning electron microscopy and photoluminescence experiments. In the present work, the objective would be to determine the role of PL emitting centers in the variations of PL intensities. Firstly, Rietveld analysis showed a decrease of cell parameters and confirmed that a solid solution was obtained. Diffraction profile analyses showed that structural distortions increasing with composition x were observed: they were ascribed to difference in cation sizes of Ce3+ and Sm3+, and to defects generated during crystal growth. The photoluminescence (PL) spectra were obtained under X-Ray (45 kV-35 mA) and UV (364.5 nm) excitations. Two PL emissions of Ce3+ were observed only under UV excitation. Four PL emissions of Sm3+ were observed under UV and X-ray excitations, and their intensities decreased with increasing composition x. Two additional transitions were observed under UV and X-ray excitations: they were attributed to oxygen vacancy defects. In the range 800 to 1000 nm, an increasing IR emission is observed: it was ascribed to emissions due to other oxygen vacancies. The main results are reported in Table 1. The chromaticity diagram (see Figure 1) showed that the colors associated with PL responses vary with Sm composition and excitation energies. This offers the opportunity to develop materials with tunable PL. To better understand this complex behavior, now, we plan to study the solid solution in the composition range x>0.3.

Exploring the role of vacancy defects in the optical properties of LiMgPO4

2020 ◽  
Vol 22 (28) ◽  
pp. 16244-16257 ◽  
Author(s):  
Pampa Modak ◽  
Brindaban Modak
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Electronic Structure ◽  
Density Functional ◽  
Structure Calculation ◽  
Hybrid Density Functional Theory ◽  
Functional Theory ◽  
Vacancy Defects ◽  
Hybrid Density Functional

A systematic electronic structure calculation employing hybrid density functional theory has been carried out to explore the role of all possible vacancy defects in neutral and charged states in the optical properties of LiMgPO4.

Role of vacancy defects in Al doped ZnO thin films for optoelectronic devices

2017 ◽  
Vol 50 (48) ◽  
pp. 485106 ◽  
Author(s):  
H Rotella ◽  
Y Mazel ◽  
S Brochen ◽  
A Valla ◽  
A Pautrat ◽  
...  
Keyword(s):  
Thin Films ◽  
Optoelectronic Devices ◽  
Zno Thin Films ◽  
Vacancy Defects ◽  
Doped Zno

scholarly journals Phononic thermal conductivity in silicene: the role of vacancy defects and boundary scattering

2018 ◽  
Vol 30 (15) ◽  
pp. 155307 ◽  
Author(s):  
M Barati ◽  
T Vazifehshenas ◽  
T Salavati-fard ◽  
M Farmanbar
Keyword(s):  
Thermal Conductivity ◽  
Boundary Scattering ◽  
Vacancy Defects
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