scholarly journals Below bandgap photoluminescence of an AlN crystal: Co-existence of two different charging states of a defect center

APL Materials ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 081107
Author(s):  
Qin Zhou ◽  
Zhaofu Zhang ◽  
Hui Li ◽  
Sergii Golovynskyi ◽  
Xi Tang ◽  
...  
Keyword(s):  
Defect Center

The influence of fusion temperature on the defect center concentration of GeO2glass

1983 ◽  
Vol 54 (9) ◽  
pp. 5394-5399 ◽  
Author(s):  
G. Kordas ◽  
R. A. Weeks ◽  
D. L. Kinser
Keyword(s):  
Fusion Temperature ◽  
Defect Center

scholarly journals Single Defect Center Scanning Near-Field Optical Microscopy on Graphene

Nano Letters ◽  
2013 ◽  
Vol 13 (7) ◽  
pp. 3152-3156 ◽  
Author(s):  
Julia Tisler ◽  
Thomas Oeckinghaus ◽  
Rainer J. Stöhr ◽  
Roman Kolesov ◽  
Rolf Reuter ◽  
...  
Keyword(s):  
Optical Microscopy ◽  
Near Field ◽  
Defect Center ◽  
Single Defect

Modification of Point Defects in Quartz for Device Applications

1983 ◽  
Vol 24 ◽  
Author(s):  
J. C. King ◽  
D. R. Koehler
Keyword(s):  
Frequency Control ◽  
Defect Center ◽  
Ir Studies ◽  
Device Applications ◽  
Temperature Ranges ◽  
Radiation Induced ◽  
Impurity Centers ◽  
Acoustic Loss ◽  
Quartz Crystal Resonators ◽  
Hostile Environments

ABSTRACTImpurity centers in quartz play a significant role in the behavior of precision crystal resonators subjected to ionizing radiation. The substitutional Al center, charge compensated by Na, Li, H or a hole, is now known to be the primary contributing factor in most radiation-induced effects. Acoustic loss measurements, ESR measurements, optical studies and IR studies of these defects, over extended temperature ranges, have contributed substantially to our understanding of the impurity centers' role. Radiation-induced frequency and acoustic loss changes in quartz crystal resonators are now understood in terms of the evolving character of the defect center in a radiation field. This understanding has prompted material modification efforts such as high temperature electrolysis and doping technologies which permit, for instance, the fabrication of frequency control devices that are little affected by hostile environments.

Electronic Structure and Reactivity of the FS(H)+Defect Center at the MgO (001) Surface

2001 ◽  
Vol 105 (40) ◽  
pp. 9798-9804 ◽  
Author(s):  
Raffaella Soave ◽  
Anna Maria Ferrari ◽  
Gianfranco Pacchioni
Keyword(s):  
Electronic Structure ◽  
Defect Center

EPR Spectroscopy of Some Mn2+ Doped Langbeinites with Regard to Low Temperature Phases

1996 ◽  
Vol 51 (10-11) ◽  
pp. 1084-1090
Author(s):  
T. Böttjer ◽  
M. Stockhausen
Keyword(s):  
Phase Transitions ◽  
Low Temperature ◽  
Large Temperature ◽  
Temperature Phase ◽  
Defect Center ◽  
Paramagnetic Resonance ◽  
Temperature Ranges ◽  
Epr Parameters ◽  
Electron Paramagnetic ◽  
Low Temperature Phase

Abstract Electron paramagnetic resonance (EPR) spectra of Mn2+ centers in 11 langbeinites, A2+B22+ (SO4)32-, with A+ = NH4+, K+, Rb+ or Tl+ and B2+ = Mg2+, Ca2+, Zn2+ or Cd2+, are measured over relatively large temperature ranges chosen to cover phase transitions, if any. For 7 langbeinites which do not contain Mg2+, phase transitions are observed, but no more than one low temperature phase is distinguishable by EPR. Except for the K-Zn langbeinite, only one defect center is noticeable in that phase. The low temperature EPR parameters are reported, and their temperature dependence is discussed with respect to correlations between structure and phase transition characteristics and to the trigger mechanism.

Redox equilibrium and spectral hole burning in Sm2+-doped Al2O3–SiO2 glasses

2002 ◽  
Vol 17 (8) ◽  
pp. 2053-2058 ◽  
Author(s):  
Masayuki Nogami ◽  
Toyonori Eto ◽  
Kazuhiro Suzuki ◽  
Tomokatsu Hayakawa
Keyword(s):  
Electron Transfer ◽  
Sol Gel ◽  
Hole Burning ◽  
Spectral Hole Burning ◽  
Oxygen Defect ◽  
Redox Equilibrium ◽  
Defect Center ◽  
X Ray ◽  
Spectral Hole ◽  
Gel Glasses

Sm2+ ion-doped Al2O3–SiO2 glasses were prepared using sol-gel and melt-quenching methods; the redox equilibrium and spectral hole burning were investigated. The Sm3+ ions were reduced into Sm2+ by heating in H2 gas or x-ray irradiation. The redox between the Sm3+ and Sm2+ obeyed first-order kinetics, the rate of which was larger for the sol-gel glasses. The Sm3+ ions were also reduced by x-ray irradiation and the activation energy for redox equilibrium was half of that for the glasses treated in H2 gas. Two different mechanisms were proposed for the redox reaction of the samarium ions. In the x-ray irradiated glasses, the Sm3+ ions were reduced into Sm2+ by electron transfer from the oxygen defect center, whereas the H2-gas reaction removed the oxygen ions to reduce the Sm3+ ions. The spectral hole burning of the x-ray-irradiated glasses could be burned by the reverse reaction of the reduction of the Sm3+ ions; that is, the electron transfer from the excited Sm2+ into the surrounding oxygen. A short distance between the Sm2+ and oxygen defect centers allowed fast hole burning. On the other hand, the hole burning in the H2-treated glasses was performed by electron transfer between Sm2+ and another trapping center such as Sm3+.

EPR Study of the Nitrogen Containing Defect Center Created in Self-Assembled 6H SiC Nanostructure

2013 ◽  
Vol 740-742 ◽  
pp. 389-392 ◽  
Author(s):  
Ekaterina N. Kalabukhova ◽  
Dariya Savchenko ◽  
Bela Shanina ◽  
Nikolai T. Bagraev ◽  
Leonid Klyachkin ◽  
...  
Keyword(s):  
The Self ◽  
Zero Field ◽  
Boron Diffusion ◽  
Spin Hamiltonian ◽  
Zero Field Splitting ◽  
Epr Spectrum ◽  
Defect Center ◽  
Field Splitting ◽  
Splitting Constant ◽  
Self Assembled

Triplet center with spin state S = 1 is detected in the EPR spectrum of the self-assembled 6H SiC nanostructure obtained by non-equilibrium boron diffusion into the n-type 6H SiC epitaxial layer (EL) under conditions of the controlled injection of the silicon vacancies at the temperature of T = 900°C. From the analysis of the angular dependences of the EPR spectrum and the numerical diagonalization of the spin Hamiltonian, the value of the zero-field splitting constant D and g-factor are found to be D = 1140•10-4см-1 and gpar = 1.9700, gper = 1.9964. Based on the hyperfine (hf) structure of the defect originating from the hf interaction with one 14N nuclei, the large value of the zero-field splitting constant D and technological conditions of the boron diffusion into the n-type 6H SiC EL, the triplet center is tentatively assigned to the defect center consisting of nitrogen atom and silicon vacancy.

The ab initio calculations of single nitrogen–vacancy defect center in diamond

2004 ◽  
Vol 348 (1-4) ◽  
pp. 292-298 ◽  
Author(s):  
M. Łuszczek ◽  
R. Laskowski ◽  
P. Horodecki
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Vacancy Defect ◽  
Nitrogen Vacancy ◽  
Defect Center
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