scholarly journals Local vibrational modes of interstitial boron-interstitial oxygen complex in silicon

2016 ◽  
Vol 213 (11) ◽  
pp. 2850-2854 ◽  
Author(s):  
L. I. Murin ◽  
S. B. Lastovskii ◽  
E. A. Tolkacheva ◽  
V. P. Markevich ◽  
A. R. Peaker ◽  
...  
Author(s):  
E. A. Tolkacheva ◽  
V. P. Markevich ◽  
L. I. Murin

The isotopic content of natural silicon (28Si (92.23 %), 29Si (4.68 %) и 30Si (3.09 %)) affects noticeably the shape of IR absorption bands related to the oxygen impurity atoms. In the present work an attempt is undertaken to determine the positions of local vibrational modes (LVMs), related to quasimolecules 28Si16OS29Si and 28Si16OS30Si (OS – substitutional oxygen atom), for the absorption spectra measured at room temperature. An estimation of the isotopic shifts of corresponding modes is done by fitting the shape of the experimentally measured absorption band related to the vacancy–oxygen center in irradiated Si crystals. The LVM isotope shifts are found to be equal 2,2 ± 0.25 cm–1 for 28Si-16OS29Si and 4,3 ± 0,9 см–1 for 28Si-16OS30Si in relation to the basic band due to 28Si-16OS28Si, and the full width at half maximum of the A-center absorption band (28Si-16OS28Si) is 5,3 ± 0.25 cm–1. By means of infrared absorption spectroscopy a clear correlation between the disappearance of the divacancy (V2) in the temperature range 200–275 ºС and appearance of two absorption bands with their maxima at 825.8 and 839.2 cm–1 in irradiated oxygen-rich Si crystals is found. The band positioned at 825.8 cm–1 is assigned to a divacancy-oxygen defect V2O formed via an interaction of mobile V2 with interstitial oxygen (Oi ) atoms. The 839.2 cm–1 band is much more pronounced in neutron irradiated samples as compared to samples irradiated with electrons. We argue that it is related to a trivacancy–oxygen defect (V3O) formed via an interaction of mobile V3 with Oi atoms.


2005 ◽  
Vol 108-109 ◽  
pp. 223-228 ◽  
Author(s):  
L.I. Murin ◽  
J. Lennart Lindström ◽  
Vladimir P. Markevich ◽  
I.F. Medvedeva ◽  
Vitor J.B. Torres ◽  
...  

We report on a combined experimental and theoretical study of the metastable form of the vacancy-dioxygen defect in Si labeled VO∗ 2. Important new experimental observations are the detection of mixed local vibrational modes of VO∗ 2 in 16O,18O co-doped samples, the determination of the position of LVM bands for the negatively charged defect, and an assignment of an acceptor level at about Ec − 0.05 eV. Defect energetics, electrical levels and LVM frequencies of the VO∗ 2 complex are also investigated by ab-initio density-functional modeling.We find it to be a bistable defect which accounts well for the experimental data. The metastable form produces an acceptor state at 0.05 eV below Ec, and can be thought of as a VO defect perturbed by interstitial oxygen.


Author(s):  
Ekaterina A. Tolkacheva ◽  
Vladimir P. Markevich ◽  
Leonid I. Murin

Isotopic composition of natural silicon (28Si (92.23 %), 29Si (4.68 %) and 30Si (3.09 %)) affects noticeably the shape of infrared absorption bands related to the oxygen impurity atoms. The positions of local vibrational modes (LVMs), related to quasimolecules 28Si – 16OS – 29Si and 28Si – 16OS – 30Si (OS – substitutional oxygen atom) have been determined for the absorption spectra measured at Т ≅ 20 K and at room temperature (Т ≅ 300 K). An estimation of the isotopic shifts of corresponding modes in a semi empirical way has been done by the fitting the shape of the experimentally measured absorption band related to the vacancy-oxygen center in irradiated Si crystals. The LVM isotope shifts at Т ≅ 300 K are found to be (2.22 ± 0.25) сm–1 for 28Si – 16OS – 29Si and (4.19 ± 0.80) сm–1 for 28Si – 16OS – 30Si in relation to the most intense band with its maximum at (830.29 ± 0.09) cm–1 due to the vibrations of  28Si – 16OS – 28Si, and the full width at half maximum of the A-center absorption bands is (5.30 ± 0.26) cm–1. At Т ≅ 20 K the corresponding values have been determined as (1.51 ± 0.13); (2.92 ± 0.20); (835.78 ± 0.01) and (2.34 ± 0.03) сm–1. A model for the calculation of isotopic shifts in the considered case has been discussed. From an analysis of the observed isotopic shifts some information about the structure of the vacancy-oxygen complex in silicon at Т ≅ 20 K and at room temperature has been obtained.


2004 ◽  
Vol 18 (19n20) ◽  
pp. 1013-1028
Author(s):  
L. HSU ◽  
M. D. McCLUSKEY

The relaxation mechanisms of local vibrational modes in solids are of central importance in understanding how such modes decay into phonons, the diffusion of impurities, and the loss of hydrogen passivation in technologically important materials. Interstitial oxygen in silicon is a model system for studying the relaxation of local vibrational modes into extended vibrational modes by measuring the interactions between the two. We have used hydrostatic pressure to bring the antisymmetric stretch mode of Si :18 O i into resonance with the second harmonic of the 18 O i resonant mode and observed an anticrossing between the two vibrational modes near pressures of 4 GPa. A theoretical model of this interaction produced excellent agreement with the experimentally observed frequencies and linewidths.


2006 ◽  
Vol 527-529 ◽  
pp. 465-468 ◽  
Author(s):  
Alexander Mattausch ◽  
M. Bockstedte ◽  
Oleg Pankratov ◽  
John W. Steeds ◽  
S.A. Furkert ◽  
...  

We observe new photoluminescence centers in electron-irradiated 6H-SiC with phonon replicas up to 250 meV and clear threefold isotope splitting of the highest energy mode. Based on ab initio calculations, we discuss the tri-carbon anti-site (C3)Si and the di-interstitial (C2)Hex as models for these centers.


2004 ◽  
Vol 84 (6) ◽  
pp. 897-899 ◽  
Author(s):  
R. Cuscó ◽  
L. Artús ◽  
D. Pastor ◽  
F. B. Naranjo ◽  
E. Calleja

1996 ◽  
Vol 69 (24) ◽  
pp. 3725-3727 ◽  
Author(s):  
W. Götz ◽  
N. M. Johnson ◽  
D. P. Bour ◽  
M. D. McCluskey ◽  
E. E. Haller

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