Temat: 78.30.Ly - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Spectroscopic Investigation of Rare-Earth Doped Phosphate Glasses Containing Silver Nanoparticles
Autorzy:: Amjad, R.
Sahar, M.
Ghoshal, S.
Dousti, M.
Samavati, M.
Riaz, S.
Tahir, B.
Tematy:: 78.30.Ly
78.55.-m
78.66.Jg; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1400152.pdf Link otwiera się w nowym oknie
Opis:: Phosphate glasses having compositions $(59.5-x)P_2O_5-40MgO-xAgCl-0.5Er_2O_3$, where x=0, 1.5 mol.% is prepared using melt-quenching technique. Infrared, absorption and photoluminescence spectra of $Er^{3+}$-doped magnesium phosphate glasses have been reported. The amorphous nature of the host glass is confirmed by X-ray diffraction technique. Transmission electron microscope image confirms the existence of silver nanoparticles inside the glass matrix. The localized surface plasmon resonance band of silver is found to be located around ≈ 528 nm for the $Er^{3+}$ free sample. A frequency upconversion process from infrared to visible is observed on excitation with 797 nm radiation. Furthermore, an enhancement in the emission at 540 nm and 632 nm is found due to the local field effect of silver nanoparticles. Our findings may contribute towards the development of solid state laser and sensors.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Study on the Structure of Defects in a-Si:H Films by Positron Annihilation and Micro-Raman Spectroscopy
Autorzy:: Gordo, P.
de Lima, A.
Ferreira Marques, M.
Kajcsos, Zs.
Tematy:: 78.66.Jg
78.70.Bj
78.30.Ly; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1812497.pdf Link otwiera się w nowym oknie
Opis:: Thin films of hydrogenated amorphous silicon deposited on glass and crystalline silicon substrates by rf plasma enhanced chemical vapor deposition at different rf power were studied using slow positron beam and the Raman scattering spectroscopy in order to verify the influence of that deposition parameter on the film defect structure and on the degree of disorder. By positron annihilation spectroscopy, it was found that there are mainly two types of defects in the films: large vacancy clusters or voids and small vacancy type defects. By micro-Raman spectroscopy it was observed that the degree of structural disorder is lower for the film with large vacancy clusters and this finding was related to structural relaxation process. Light soaking induced changes attributed to major atomic rearrangements were also observed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Damage Assessment in Low Doses $\text{}^{30}Si^{+}$-Implanted GaAs
Autorzy:: Desnica Franković, D.
Desnica, V.
Furić, K.
Tematy:: 78.30.Ly
61.72.Vv
63.50.+x; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1807802.pdf Link otwiera się w nowym oknie
Opis:: Ion implantation is a widely used technique in device technology, and becoming even more important as the size of devices decreases. The studies of damage and introduced defects have been extensive and, although the overall development and annealing of the implantation damage is relatively well understood, many details remain unclear. Especially, not enough attention has been paid to the effects of very low doses, which are particularly important in controlling the threshold voltage of transistors in the fabrication of GaAs integrated circuits. The reason might be that the induced changes were very often below the detectivity limits of standard methods. In this work, we present the disorder analysis, conducted on GaAs implanted with low ion doses. Czochralski grown, undoped, (100) oriented GaAs samples were implanted with 100 keV $\text{}^{30}Si^{+}$ ions, doses ranging from 3×$10^{11}//cm^{2}$-3×$10^{13}//cm^{2}$, at 21°C. The damage assessment was done by applying Raman scattering and Rutherford backscattering ion channeling (RBS), linked by the inter-cascade distance model and the results were then compared with the results of photoacoustic displacement technique. We have shown that Raman scattering is very sensitive method even if applied on samples implanted with very low doses. Furthermore, the equivalency between the Raman scattering and Rutherford backscattering damage assessment, previously established for high doses via the inter-cascade distance model, proved equally valid also for very low implantation doses, where implanted ions create disordered cascades that are far apart, and most of the layer is still undamaged.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: The Effect of Power Density on Diffusion Length and Energy Gap of a-Si:H and nc-Si:H Thin Films Prepared by PECVD Technique
Autorzy:: Badran, R.
Al-Amodi, H.
Yaghmour, S.
Shaklan, S.
Bruggemann, R.
Han, X.
Xiong, S.
Tematy:: 78.20.-e
78.20.Ci
73.61.Jc
78.30.Ly; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1419002.pdf Link otwiera się w nowym oknie
Opis:: The increase in power density of 0.3, 0.5, 0.6, and 0.7 W $cm^{-2}$ for hydrogenated amorphous and nanocrystalline silicon (a-Si:H and nc-Si:H) thin film samples prepared by plasma enhanced chemical vapor deposition technique causes an increase in crystalline volume fraction when the silane concentration is fixed. This increase in crystalline volume fraction is correlated to the absorption coefficient and refractive index which are determined from ellipsometric measurements. The crystallinity of samples is studied by both Raman and X-ray diffraction techniques. A mild change in the optical energy gap around an average value of 1.8 eV is noticed due to the observed change in the degree of crystallinity of the samples when power density increases. Moreover, the ambipolar diffusion length measured by the steady-state photocarrier grating technique is found to change with the increase in power density. The values of some obtained optical parameters are compared to a standard crystalline sample.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Investigation of Infrared and Raman Spectra of $TeO_2-Nb_2O_5-TiO_2$ Glasses
Autorzy:: Kabalci, İ.
Gökçe, H.
Tematy:: 42.70.Ce
61.05.Cp
82.80.Gk
78.30.Ly; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1360392.pdf Link otwiera się w nowym oknie
Opis:: X-ray diffraction, infrared (IR), Raman spectroscopy and scanning electron microscope techniques have been used to investigate the microstructural properties of the glass materials. In this work, a new type of tellurite based optical glasses with $TeO_2$/$Nb_2O_5$/$TiO_2$ for different $xNb_2O_5$ (x = 5, 10, 15, and 20 mol.%) glass compositions at constant 5 mol.% $TiO_2$ ratio were prepared. The effect of $Nb_2O_5$ contents on the structural unit of $(95-x)TeO_2-(x)Nb_2O_5-5TiO_2$ glass network, and the intensity ratios of the Raman peaks were investigated. The results indicate that for different $Nb_2O_5$ content 5 to 20 mol.% in the glass system, three vibrational peaks around 650, 800, and 920 $cm^{-1}$ which correspond to the structural bonding of the glass were observed in the range of 500-2000 $cm^{-1}$ for the IR spectra. Furthermore, from the Raman results a structural evolution was determined with the number of structural units such as $[NbO_6]^{7-}$, $TeO_{3+1}$ (polyhedra), $TeO_4$ (trigonal bipyramids), $TeO_3$ (trigonal pyramids) or $TeO_{3+1}$ (polyhedra), and $[NbO_4]^{3-}$ for this ternary glass system.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: A Model Calculation of Infrared Spectra in Cyclohexanol
Autorzy:: Nowina Konopka, M.
Wasiutyński, T.
Tematy:: 61.50.Ah
63.20.Dj
78.20.Bh
78.30.Jw
78.30.Ly; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2011075.pdf Link otwiera się w nowym oknie
Opis:: A model calculation based on semiempirical methods for the cyclohexanol molecules is presented. Energetically preferred molecular conformations and possibility of different hydrogen bond networks in the crystal are discussed. The calculated and the experimental infrared spectra are compared. The results corroborate earlier suggestions that the rich polymorphism of cyclohexanol is due to the existence of both axial and equatorial isomers in solid phases and different architecture of hydrogen bonds network.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Bioactive Glass Coatings Synthesized by Pulsed Laser Deposition Technique
Autorzy:: Kwiatkowska, J.
Suchanek, K.
Rajchel, B.
Tematy:: 61.43.Fs
63.50.Lm
78.30.Ly
81.15.Fg
87.85.J-; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1490183.pdf Link otwiera się w nowym oknie
Opis:: Surface modification of medical implants is often required to improve their biocompatibility or, through bioactive properties of the surface material, facilitate its intergrowth with the living tissue. Bioactive-glass coatings can serve that purpose for the bone implants. We report a successful preparation of silicate-phosphate bioactive-glass coating on titanium substrate using the pulsed laser deposition method and present the coating characterization in terms of bonding configuration and chemical activity. The former was studied with high-resolution Raman microspectroscopy and revealed the presence of structural units responsible for the material's bioactivity. The bioactivity was also tested directly, in vitro, by soaking the samples in the simulated body fluid and examining the result with the Raman spectroscopy. The Raman spectrum, typical of hydroxyapatite was observed proving that the bone-like-material formed on the coating's surface.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: FTIR Study of Nanostructure Perovskite $BaTiO_3$ Doped with Both $Fe^{3+}$ and $Ni^{2+}$ Ions Prepared by Sol-Gel Technique
Autorzy:: Abdel Aal, A.
Hammad, T.
Zawrah, M.
Battisha, I.
Abou Hammad, A.
Tematy:: 81.20.Fw
81.07.Bc
64.70.kg
61.05.C-
78.30.Ly
81.10.Aj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1377829.pdf Link otwiera się w nowym oknie
Opis:: Pure barium titanate $BaTiO_3 (BT)$ and BT doped with two different transition elements $Fe^{3+}$ and $Ni^{2+}$ at 5 mol.% (BT5Fe and BT5Ni, respectively) as constant concentration in powder form have been prepared by sol-gel method using barium acetate, titanium(IV) n-butoxide, iron and nickel nitrates as precursor materials. The microstructure of BT and the influence of Fe and Ni dopants on it were investigated by X-ray diffraction and Fourier transform infrared spectroscopy. X-ray diffraction shows that tetragonal phase is dominant for pure BT sintered for 4 h at 800°C. Scanning electron microscopy and transmission electron microscopy were used to study surface morphology and particle size distribution for BT5Fe and BT5Ni, respectively. The presence of hydroxyl defects were verified by Fourier transform infrared spectroscopy for $(BaTi_{1-x}Fe_{x}O_{3-x/2}) (BT_xFe)$, where x=0.005, 0.01, 0.05, and 0.07 and $(BaTi_{1-x}Ni_{x}O_{3-x/2}) (BT_xNi)$, where x=0.005, 0.01, 0.03, 0.05, and 0.07.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Thermo-Optical Parameters of Amorphous a-C:N:H Layers
Autorzy:: Pieczyńska, E.
Jaglarz, J.
Marszalek, K.
Tkacz-Śmiech, K.
Tematy:: 07.60.Fs
78.20.-e
78.20.Ci
78.20.N-
78.30.Ly
81.05.U-
81.15.Gh; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1377543.pdf Link otwiera się w nowym oknie
Opis:: Thermo-optical properties of hydrogenated amorphous carbon nitride layers (a-C:N:H) deposited on crystalline silicon by plasma assisted chemical vapour deposition were studied. The layers were characterized by the Fourier transform infrared spectroscopy and their chemical composition, i.e. [N]/[C] ratio, was determined by energy dispersive X-ray technique. The optic measurements were made by spectroscopic ellipsometer Wollam M2000 equipped with a heated vacuum chamber. The measurements of ellipsometric angles were carried out during heating the sample from room temperature to 300°C. Refractive index, extinction coefficient and the layer thicknesses were calculated by fitting the model of the layer to the ellipsometric data. The results confirm that at about 23°C the layer properties are changed. The measured thermo-optical parameters, dn/dT and dk/dT, show abrupt change from negative to positive values which can be explained by structure graphitization. Simultaneously, the bandgap decreases from 2.5 to 0.7 eV and the layer thickness drops to about 50% of the initial value.
Dostawca treści:: Biblioteka Nauki

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