Local Vibrations of Substitutional Carbon in SiGe Alloys

2006 ◽  
Vol 514-516 ◽  
pp. 364-368 ◽  
Author(s):  
Lyudmila I. Khirunenko ◽  
Yu.V. Pomozov ◽  
Mikhail G. Sosnin ◽  
Vitor J.B. Torres ◽  
João A.P. Coutinho ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Absorption Band ◽  
Single Crystals ◽  
Vibrational Mode ◽  
Mode Frequency ◽  
Difference Spectra ◽  
Modeling Methods ◽  
Local Vibrational Mode ◽  
The Difference ◽  
Fractional Content

The influence of Ge content on the local vibrational mode of substitutional carbon in Si-rich Si1-xGex single crystals has been investigated by infrared Fourier-transform spectroscopy and ab initio modeling methods. Czochralski-grown Si1-xGex samples doped with boron and carbon have been studied. The Ge fractional content was varied from x=0.004 to x=0.044. To reveal the CS-related absorption band in the Si1-xGex the difference spectra between carbon-lean and carbon-reach Si1-xGex samples with the same Ge content were studied. We have found that the CS-related absorption band in the Si1-xGex alloys red-shifts and broadens with increasing Ge content. It has been found that at x0.015 the CS absorption band consists of two overlapping lines corresponding to different combinations of Si and Ge atoms neighboring the CS atom. The calculations show that substitutional carbon atoms avoid Ge ligand atoms, and should be found in Si-rich regions. These results also reveal that the softening of the CS mode frequency arises from the SiGe volumic expansion.

Divacancy-Oxygen and Trivacancy-Oxygen Complexes in Silicon: Local Vibrational Mode Studies

2009 ◽  
Vol 156-158 ◽  
pp. 129-134 ◽  
Author(s):  
L.I. Murin ◽  
Bengt Gunnar Svensson ◽  
J. Lennart Lindström ◽  
Vladimir P. Markevich ◽  
Charalamos A. Londos
Keyword(s):  
Fourier Transform ◽  
Room Temperature ◽  
Vibrational Mode ◽  
Clear Correlation ◽  
Interstitial Oxygen ◽  
Infrared Absorption Spectroscopy ◽  
Oxygen Defect ◽  
Absorption Bands ◽  
Local Vibrational Mode ◽  
Oxygen Complexes

Fourier transform infrared absorption spectroscopy was used to study the evolution of multivacancy-oxygen-related defects in the temperature range 200-300 °C in Czochralski-grown Si samples irradiated with MeV electrons or neutrons. A clear correlation between disappearance of the divacancy (V2) related absorption band at 2767 cm-1 and appearance of two absorption bands positioned at 833.4 and 842.4 cm-1 at 20 K (at 825.7 and 839.1 cm-1 at room temperature) has been found. Both these two emerging bands have previously been assigned to a divacancy-oxygen defect formed via interaction of mobile V2 with interstitial oxygen (Oi) atoms. The present study shows, however, that the two bands arise from different defects since the ratio of their intensities depends on the type of irradiation. The 842.4 cm-1 band is much more pronounced in neutron irradiated samples and we argue that it is related to a trivacancy-oxygen defect (V3O) formed via interaction of mobile V3 with Oi atoms or/and interaction of mobile V2 with VO defects.

Trivacancy-oxygen complex in silicon: Local vibrational mode characterization

2009 ◽  
Vol 404 (23-24) ◽  
pp. 4568-4571
Author(s):  
L.I. Murin ◽  
B.G. Svensson ◽  
J.L. Lindström ◽  
V.P. Markevich ◽  
C.A. Londos
Keyword(s):  
Vibrational Mode ◽  
Local Vibrational Mode ◽  
Oxygen Complex

The interaction of bovine milk caseins with the detergent sodium dodecyl sulphate. II. The effect of detergent binding on spectral properties of caseins

1970 ◽  
Vol 37 (2) ◽  
pp. 259-267 ◽  
Author(s):  
G. C. Cheeseman ◽  
Dorothy J. Knight
Keyword(s):  
Sodium Dodecyl Sulphate ◽  
Sodium Dodecyl ◽  
Bovine Milk ◽  
Difference Spectrum ◽  
Temperature Dependent ◽  
Difference Spectra ◽  
Negative Change ◽  
Tryptophan Residues ◽  
Hydrophobic Binding ◽  
The Difference

SummaryThe dissociation of casein aggregates by the detergent sodium dodecyl sulphate (SDS) gave rise to difference spectra and these spectra were characteristic for each of the different types of casein. Increase in absorption by the chromophore groups, tyrosine and tryptophan, when αs1- and β-casein aggregates were dissociated indicated binding of the detergent at regions of the molecule containing these residues. A decrease in absorption when κ-casein was dissociated indicated that the tyrosine and tryptophan residues were not in the region of the molecule to which the detergent was bound and that in the κ-casein aggregate these residues were in a more hydrophobic environment. Peaks on the difference spectra were obtained at 280 and 288 nm for αs1-casein and 284 and 291 nm for β-casein and troughs at 278 and 286 nm for κ-casein. The difference spectrum reached a maximum value when the αsl- and β-casein aggregates were dissociated and the further binding of SDS did not alter this value. The large negative change in the difference spectrum of κ-casein did not occur until after most of the aggregates were dissociated and did not reach a maximum until binding with SDS was complete. The value obtained for ΔOD was found to be temperature-dependent for β-casein-SDS interaction, but not for αs1- and κ-casein. Changes in spectra were also observed when αs1- and κ-casein interacted to form aggregates. The data obtained confirmed the importance of hydrophobic binding in casein aggregate formation and indicated the possible involvement of tyrosine and tryptophan residues in this binding.

Quantitative assessment of Be acceptors in GaAs by local vibrational mode spectroscopy

1991 ◽  
Vol 69 (2) ◽  
pp. 971-974 ◽  
Author(s):  
J. Wagner ◽  
M. Maier ◽  
R. Murray ◽  
R. C. Newman ◽  
R. B. Beall ◽  
...  
Keyword(s):  
Quantitative Assessment ◽  
Vibrational Mode ◽  
Local Vibrational Mode ◽  
Mode Spectroscopy

Depth Profile Study of Large-Sized Coal Samples by Fourier Transform Infrared Photoacoustic Spectroscopy

1986 ◽  
Vol 40 (2) ◽  
pp. 214-217 ◽  
Author(s):  
Tiziana Zerlia
Keyword(s):  
Fourier Transform ◽  
Depth Profile ◽  
Photoacoustic Spectroscopy ◽  
Modulation Frequency ◽  
Fourier Transform Infrared ◽  
Qualitative Description ◽  
Difference Spectra ◽  
Compositional Depth Profile ◽  
Ft Ir ◽  
Infrared Photoacoustic Spectroscopy

A multidisciplinary approach is demonstrated to elucidate coal weathering at a molecular level. Fourier Transform Infrared Photoacoustic Spectroscopy (FT-IR/PAS) provides a technique for a compositional depth profile of coal by simply varying the modulation frequency (mirror velocity) of the light impinging upon the solid surface. In order that the potential of this technique in this field could be evaluated, large-sized coal samples were examined. The PA difference spectra obtained from the spectra taken at different modulation frequencies (i.e., different depths), on a sample aged in air, demonstrate the appearance of negative features in the CH infrared absorption which are indicative of a coal alteration. Therefore, different coal layers can be distinguished by FT-IR/PAS. The application of the same technique to the study of a coal sample heated in air at 200°C allows the detection of different oxidation mechanisms operating inside and outside the coal. Although quantitative results are difficult to obtain, the technique can be successfully proposed for a qualitative description of coal weathering.

The mechanism of work-hardening and slip-band formation

1957 ◽  
Vol 242 (1229) ◽  
pp. 147-159 ◽  
Keyword(s):  
Single Crystals ◽  
Slip Band ◽  
Work Hardening ◽  
Stage I ◽  
Polycrystalline Materials ◽  
Temperature Dependent ◽  
Band Formation ◽  
Slip Bands ◽  
Three Stages ◽  
The Difference

A summary is given of some present ideas on the mechanism of work-hardening of single crystals and polycrystalline materials. In particular, the difference is stressed between the three stages of hardening: stage I, or easy glide; stage II, the region of rapid hardening accompanied by short slip lines; and stage III, the region of slow or parabolic hardening which is temperature-dependent and in which long slip bands are formed.

scholarly journals Distance Metrics of D Numbers

2020 ◽  
Author(s):  
Liguo Fei ◽  
Yuqiang Feng
Keyword(s):  
Number Theory ◽  
Incomplete Information ◽  
Distance Function ◽  
Distance Measure ◽  
Complete Information ◽  
Belief Function ◽  
Distance Metrics ◽  
Modeling Methods ◽  
The Difference ◽  
D Numbers

Belief function has always played an indispensable role in modeling cognitive uncertainty. As an inherited version, the theory of D numbers has been proposed and developed in a more efficient and robust way. Within the framework of D number theory, two more generalized properties are extended: (1) the elements in the frame of discernment (FOD) of D numbers do not required to be mutually exclusive strictly; (2) the completeness constraint is released. The investigation shows that the distance function is very significant in measuring the difference between two D numbers, especially in information fusion and decision. Modeling methods of uncertainty that incorporate D numbers have become increasingly popular, however, very few approaches have tackled the challenges of distance metrics. In this study, the distance measure of two D numbers is presented in cases, including complete information, incomplete information, and non-exclusive elements

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