scholarly journals Diamonds from the Mir Pipe (Yakutia): Spectroscopic Features and Annealing Studies

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 366
Author(s):  
Mariana I. Rakhmanova ◽  
Andrey Yu. Komarovskikh ◽  
Yuri N. Palyanov ◽  
Alexander A. Kalinin ◽  
Olga P. Yuryeva ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Nickel Complexes ◽  
Nitrogen Diffusion ◽  
Double Peak ◽  
Paramagnetic Resonance ◽  
Interstitial Carbon ◽  
Temperature Range ◽  
Carbon Vacancy ◽  
Electron Paramagnetic ◽  
Annealing Experiments

For this study, 21 samples of colorless octahedral diamonds (weighing 5.4–55.0 mg) from the Mir pipe (Yakutia) were investigated with photoluminescence (PL), infrared (IR), and electron paramagnetic resonance (EPR) spectroscopies. Based on the IR data, three groups of diamonds belonging to types IIa, IaAB, and IaB were selected and their spectroscopic features were analyzed in detail. The three categories of stones exhibited different characteristic PL systems. The type IaB diamonds demonstrated dominating nitrogen–nickel complexes S2, S3, and 523 nm, while they were less intensive or even absent in the type IaAB crystals. The type IIa diamonds showed a double peak at 417.4+418.7 nm (the 418 center in this study), which is assumed to be a nickel–boron defect. In the crystals analyzed, no matter which type, 490.7, 563.5, 613, and 676.3 nm systems of various intensity could be detected; moreover, N3, H3, and H4 centers were very common. The step-by-step annealing experiments were performed in the temperature range of 600–1700 °C. The treatment at 600 °C resulted in the 563.5 nm system’s disappearance; the interstitial carbon vacancy annihilation could be considered as a reason. The 676.5 nm and 613 nm defects annealed out at 1500 °C and 1700 °C, respectively. Furthermore, as a result of annealing at 1500 °C, the 558.5 and 576 nm centers characteristic of superdeep diamonds from São Luis (Brazil) appeared. These transformations could be explained by nitrogen diffusion or interaction with the dislocations and/or vacancies produced.

Intrinsic Defects in HPSI 6H-SiC: an EPR Study

2008 ◽  
Vol 600-603 ◽  
pp. 381-384 ◽  
Author(s):  
Patrick Carlsson ◽  
Nguyen Tien Son ◽  
Björn Magnusson ◽  
Anne Henry ◽  
Erik Janzén
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Vapor Deposition ◽  
Thermal Activation ◽  
Chemical Vapor ◽  
Paramagnetic Resonance ◽  
Intrinsic Defects ◽  
Annealing Behavior ◽  
Carbon Vacancy ◽  
The Stability ◽  
Electron Paramagnetic

High-purity, semi-insulating 6H-SiC substrates grown by high-temperature chemical vapor deposition were studied by electron paramagnetic resonance (EPR). The carbon vacancy (VC), the carbon vacancy-antisite pair (VCCSi) and the divacancy (VCVSi) were found to be prominent defects. The (+|0) level of VC in 6H-SiC is estimated by photoexcitation EPR (photo-EPR) to be at ~ 1.47 eV above the valence band. The thermal activation energies as determined from the temperature dependence of the resistivity, Ea~0.6-0.7 eV and ~1.0-1.2 eV, were observed for two sets of samples and were suggested to be related to acceptor levels of VC, VCCSi and VCVSi. The annealing behavior of the intrinsic defects and the stability of the SI properties were studied up to 1600°C.

scholarly journals The Carbon Vacancy Related EI4 Defect in 4H-SiC

2010 ◽  
Vol 645-648 ◽  
pp. 399-402 ◽  
Author(s):  
Nguyen Tien Son ◽  
Patrick Carlsson ◽  
Junichi Isoya ◽  
Norio Morishita ◽  
Takeshi Ohshima ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
High Purity ◽  
Room Temperature ◽  
Paramagnetic Resonance ◽  
Annealing Behaviour ◽  
Carbon Vacancy ◽  
Epr Signal ◽  
Electron Paramagnetic

Electron paramagnetic resonance (EPR) was used to study high-purity semi-insulating 4H-SiC irradiated with 2 MeV electrons at room temperature. The EPR signal of the EI4 defect was found to be dominating in samples irradiated and annealed at ~750°C. Additional large-splitting 29Si hyperfine (hf) lines and also other 13C and 29Si hf structures were observed. Based on the observed hf structures and annealing behaviour, the complex between a negative carbon vacancy-carbon antisite pair (VCCSi–) and a distance positive carbon vacancy ( ) is tentatively proposed as a possible model for the EI4 defect.

Vacancies In Electron Irradiated 6H-SiC

1996 ◽  
Vol 442 ◽  
Author(s):  
T. Friessnegg ◽  
S. Dannefaer
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Temperature Interval ◽  
Paramagnetic Resonance ◽  
Carbon Vacancy ◽  
Electron Paramagnetic ◽  
Major Reduction ◽  
Positively Charged

AbstractAnnealing of electron irradiated bulk n-type 6H-SiC has shown that neutral carbon vacancies and neutral silicon vacancies undergo a major reduction in concentration in the 20–200 °C temperature interval after which only slight changes occur up to 1200 °C. The experiments suggest that the positively charged carbon vacancy, detected by electron paramagnetic resonance, constitutes only a small fraction of all carbon vacancies.

Intrinsic Defects in Semi-Insulating SiC: Deep Levels and their Roles in Carrier Compensation

2007 ◽  
Vol 556-557 ◽  
pp. 465-468 ◽  
Author(s):  
Nguyen Tien Son ◽  
Patrick Carlsson ◽  
Björn Magnusson ◽  
Erik Janzén
Keyword(s):  
Electron Paramagnetic Resonance ◽  
High Purity ◽  
Thermal Activation ◽  
Activation Energies ◽  
Deep Levels ◽  
Paramagnetic Resonance ◽  
Intrinsic Defects ◽  
Carbon Vacancy ◽  
Reported Data ◽  
Electron Paramagnetic

Vacancies, divacancies and carbon vacancy-carbon antisite pairs are found by electron paramagnetic resonance (EPR) to be dominant defects in high-purity semi-insulating (HPSI) 4HSiC substrates having different thermal activation energies of the resistivity ranging from ~0.8 eV to ~1.6 eV. Based on EPR results and previously reported data, the energy positions of several acceptor states of the vacancies and vacancy-related complexes are estimated. These deep levels are suggested to be associated to different thermal activation energies and responsible for the semiinsulating behaviour in HPSI SiC substrates. Their role in carrier compensation is discussed.

Defect Structure of Nanosized Zirconium Oxide Powders Doped with Y2O3, Sc2O3, Cr2O3

2013 ◽  
Vol 200 ◽  
pp. 108-113
Author(s):  
Lesya P. Yurchenko ◽  
Igor P. Bykov ◽  
Alexander B. Brik ◽  
Oleksandr D. Vasylyev ◽  
Valeriy G. Vereschak ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Zirconium Oxide ◽  
Defect Structure ◽  
Formation Mechanisms ◽  
Paramagnetic Centers ◽  
Thermal Generation ◽  
Paramagnetic Resonance ◽  
Temperature Range ◽  
Oxide Powders ◽  
Electron Paramagnetic

The formation mechanisms of paramagnetic centers originating from Zr3+ and Cr3+ ions and the influence of the nanoparticle composition on thermal generation processes of these paramagnetic centers in ZrO2 structure were studied by electron paramagnetic resonance. A set of nanosized zirconium oxide powders (nominally pure ZrO2, ZrO2 doped with correspondingly Y2O3 and Sc2O3, Cr2O3 and Y2O3, as well as Cr2O3) was investigated: The influence of annealing on the EPR lines of Zr3+ and Cr5+ ions was found to be different. Annealing curves of EPR signals caused by Cr5+ ions have a maximum in temperature range 500–600 °C. Mechanisms of Zr3+ and Cr5+ ions formation were discussed.

Deep Levels Responsible for Semi-Insulating Behavior in Vanadium-Doped 4H-SiC Substrates

2008 ◽  
Vol 600-603 ◽  
pp. 401-404
Author(s):  
Nguyen Tien Son ◽  
Patrick Carlsson ◽  
Andreas Gällström ◽  
Björn Magnusson ◽  
Erik Janzén
Keyword(s):  
Activation Energy ◽  
Electron Paramagnetic Resonance ◽  
Thermal Activation ◽  
Activation Energies ◽  
Thermal Activation Energy ◽  
Deep Levels ◽  
Paramagnetic Resonance ◽  
Intrinsic Defects ◽  
Carbon Vacancy ◽  
Electron Paramagnetic

Semi-insulating (SI) 4H-SiC substrates doped with vanadium (V) in the range 5.5×1015 –1.1×1017 cm–3 were studied by electron paramagnetic resonance. We show that only in heavily V-doped 4H-SiC vanadium is responsible for the SI behavior, whereas in moderate V-doped substrates with the V concentration comparable or slightly higher than that of the shallow N donor or B acceptor, the SI properties are thermally unstable and determined by intrinsic defects. The results show that the commonly observed thermal activation energy Ea~1.1 eV in V-doped 4H-SiC, which was previously assigned to the single acceptor V4+/3+ level, may be related to deep levels of the carbon vacancy. Carrier compensation processes involving deep levels of V and intrinsic defects are discussed and possible thermal activation energies are suggested.

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