High Energy Local Vibrational Modes of Carbon Aggregates in SiC: Experimental and Theoretical Insight

Author(s):  
Alexander Mattausch ◽  
M. Bockstedte ◽  
Oleg Pankratov ◽  
John W. Steeds ◽  
S.A. Furkert ◽  
...  
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.


1999 ◽  
Vol 4 (S1) ◽  
pp. 327-332 ◽  
Author(s):  
A. Kaschner ◽  
H. Siegle ◽  
A. Hoffmann ◽  
C. Thomsen ◽  
U. Birkle ◽  
...  

We present results of Raman-scattering experiments on GaN doped with Si, C, and Mg, respectively, grown by molecular beam epitaxy (MBE). The influence of the different dopants on strain and free-carrier concentration was investigated. Furthermore, we report on several local vibrational modes (LVM) around 2200 cm−1 in Raman spectra of highly Mg-doped GaN. A possible explanation of these high-energy modes in terms of hydrogen-related vibrations is given. We also found a variety of new structures in the range of the GaN host lattice phonons. Secondary ion mass spectroscopy (SIMS) was applied to determine the concentration of magnesium and unintentionally incorporated hydrogen.


1998 ◽  
Vol 537 ◽  
Author(s):  
A. Kaschner ◽  
H. Siegle ◽  
A. Hoffmann ◽  
C. Thomsen ◽  
U. Birkle ◽  
...  

AbstractWe present results of Raman-scattering experiments on GaN doped with Si, C, and Mg, respectively, grown by molecular beam epitaxy (MBE). The influence of the different dopants on strain and free-carrier concentration was investigated. Furthermore, we report on several local vibrational modes (LVM) around 2200 cm-1 in Raman spectra of highly Mg-doped GaN. A possible explanation of these high-energy modes in terms of hydrogen-related vibrations is given. We also found a variety of new structures in the range of the GaN host lattice phonons. Secondary ion mass spectroscopy (SIMS) was applied to determine the concentration of magnesium and unintentionally incorporated hydrogen.


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

2006 ◽  
Vol 73 (22) ◽  
Author(s):  
A. Dubroka ◽  
J. Humlíček ◽  
M. V. Abrashev ◽  
Z. V. Popović ◽  
F. Sapiña ◽  
...  

1996 ◽  
Vol 159 (1-4) ◽  
pp. 889-892 ◽  
Author(s):  
I. Broser ◽  
G. Kaczmarczyk ◽  
P. Thurian ◽  
R. Heitz ◽  
A. Hoffmann

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.


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