Infrared dielectric function and phonon modes of Mg-rich cubic MgxZn1−xO(x⩾0.67) thin films on sapphire (0001)

2004 ◽  
Vol 85 (6) ◽  
pp. 905-907 ◽  
Author(s):  
C. Bundesmann ◽  
M. Schubert ◽  
A. Rahm ◽  
D. Spemann ◽  
H. Hochmuth ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Function ◽  
Phonon Modes

Infrared dielectric function and vibrational modes of pentacene thin films

2004 ◽  
Vol 84 (2) ◽  
pp. 200-202 ◽  
Author(s):  
M. Schubert ◽  
C. Bundesmann ◽  
G. Jacopic ◽  
H. Maresch ◽  
H. Arwin
Keyword(s):  
Thin Films ◽  
Dielectric Function ◽  
Vibrational Modes

Chemical Bath Deposition of Lead Sulphide (PbS) Thin Film and their Characterization

2013 ◽  
Vol 209 ◽  
pp. 111-115 ◽  
Author(s):  
Sandip V. Bhatt ◽  
M.P. Deshpande ◽  
Bindiya H. Soni ◽  
Nitya Garg ◽  
Sunil H. Chaki
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Raman Spectroscopy ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Excitation Wavelength ◽  
Face Centered Cubic ◽  
Phonon Modes ◽  
Lead Sulphide ◽  
X Ray

Thin film deposition of PbS is conveniently carried out by chemical reactions of lead acetate with thiourea at room temperature. Energy dispersive analysis of X-ray (EDAX), X-ray diffraction (XRD), selected area electron diffraction patterns (SAED), UV-Vis-NIR spectrophotometer, Scanning Electron Microscopy (SEM), Atomic force microscopy (AFM), Photoluminescence (PL) and Raman spectroscopy techniques are used for characterizing thin films. EDAX spectra shows that no impurity is present and XRD pattern indicates face centered cubic structure of PbS thin films. The average crystallite size obtained using XRD is about 15nm calculated using Scherrer’s formula and that determined from Hall-Williamson plot was found to be 18nm. SAED patterns indicate that the deposited PbS thin films are polycrystalline in nature. Blue shift due to quantum confinement was seen from the UV-Vis-NIR absorption spectra of thin film in comparison with bulk PbS. The Photoluminescence spectra obtained for thin film with different excitation sources shows sharp emission peaks at 395nm and its intensity of photoluminescence increases with increasing the excitation wavelength. Raman spectroscopy of deposited thin film was used to study the optical phonon modes at an excitation wavelength of 488nm using (Ar+) laser beam.

Structural and Surface Characteristics of CuO and Pt/CuO Nanostructured Thin Films

2021 ◽  
Vol 14 (5) ◽  
pp. 419-424
Keyword(s):  
Thin Films ◽  
Optical Fibers ◽  
Structural Information ◽  
Surface Characteristics ◽  
X Ray Diffraction ◽  
Phonon Modes ◽  
Silar Method ◽  
Nanostructured Thin Films ◽  
Average Grain Size ◽  
Sem Micrograph

Abstract: The most prominent and utilizable platinum-coated copper Oxide nanostructured thin films are prepared using the SILAR method. Their structural properties have been studied using X-ray diffraction (XRD) and Raman spectroscopy. XRD pattern reveals the phase purity and crystallinity of CuO nanostructures. The average grain size estimated from XRD gives diameters in the range of 14 - 27 nm. Raman spectra explain the structural information of CuO and Pt/CuO nanostructured thin films, in which the peaks observed at 328 cm-1, 609.32 cm-1 and 1141.77 cm-1 are the different phonon modes of CuO. The peak at 2136 cm-1 provides strong evidence for the formation of platinum on CuO nanostructures. The SEM micrograph confirms the floral morphology, which is composed of nano petals. From the observed morphology, it is observed that the deposited thin films such as CuO and Pt/CuO will give interesting applications to our society by being self-cleaning agents, photocatalysts, semiconductor devices, optical fibers, … etc. Keywords: CuO, Pt/CuO, Structural analysis, SILAR, Crystallinity.

scholarly journals Temperature-dependent optical and vibrational properties of PtSe2 thin films

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Desman P. Gulo ◽  
Han Yeh ◽  
Wen-Hao Chang ◽  
Hsiang-Lin Liu
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Room Temperature ◽  
Near Infrared ◽  
Technological Development ◽  
Phonon Modes ◽  
Research Attention ◽  
Practical Applications ◽  
Infrared Frequency Range ◽  
Indirect Band Gap

Abstract PtSe2 has received substantial research attention because of its intriguing physical properties and potential practical applications. In this paper, we investigated the optical properties of bilayer and multilayer PtSe2 thin films through spectroscopic ellipsometry over a spectral range of 0.73–6.42 eV and at temperatures between 4.5 and 500 K. At room temperature, the spectra of refractive index exhibited several anomalous dispersion features below 1000 nm and approached a constant value in the near-infrared frequency range. The thermo-optic coefficients of bilayer and multilayer PtSe2 thin films were (4.31 ± 0.04) × 10−4/K and (–9.20 ± 0.03) × 10−4/K at a wavelength of 1200 nm. Analysis of the optical absorption spectrum at room temperature confirmed that bilayer PtSe2 thin films had an indirect band gap of approximately 0.75 ± 0.01 eV, whereas multilayer PtSe2 thin films exhibited semimetal behavior. The band gap of bilayer PtSe2 thin films increased to 0.83 ± 0.01 eV at 4.5 K because of the suppression of electron–phonon interactions. Furthermore, the frequency shifts of Raman-active Eg and A1g phonon modes of both thin films in the temperature range between 10 and 500 K accorded with the predictions of the anharmonic model. These results provide basic information for the technological development of PtSe2-based optoelectronic and photonic devices at various temperatures.

The dielectric function of Mgy NiHx thin films ()

2007 ◽  
Vol 430 (1-2) ◽  
pp. 13-18 ◽  
Author(s):  
W. Lohstroh ◽  
R.J. Westerwaal ◽  
J.L.M. van Mechelen ◽  
H. Schreuders ◽  
B. Dam ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Function

Characterization of dielectric function for metallic thin films based on ellipsometric parameters and reflectivity

2019 ◽  
Vol 94 (8) ◽  
pp. 085802 ◽  
Author(s):  
Jiamin Liu ◽  
Jianbin Lin ◽  
Hao Jiang ◽  
Honggang Gu ◽  
Xiuguo Chen ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Function ◽  
Metallic Thin Films

INTERFACE AND STEP LOCALIZED PHONON MODES BETWEEN TWO TRUNCATED THIN FILMS

2004 ◽  
Vol 11 (02) ◽  
pp. 155-165
Author(s):  
M. TAMINE ◽  
H. BOUMRAR ◽  
O. RAFIL
Keyword(s):  
Thin Films ◽  
Strain Field ◽  
Phonon Dispersion ◽  
Harmonic Approximation ◽  
Elastic Force ◽  
Force Constants ◽  
Step Edge ◽  
Dimensional Structure ◽  
Phonon Modes ◽  
Low Dimensional

We have carried out the calculations of vibrational dynamics in the low-dimensional structure with dimensions on the nanometer scale by using the matching formalism. The nanostructure model consists in the surface step produced at a perpendicular interface between two truncated thin films with different thickness. The theoretical approach determines the vibrational field in the direction where the translation symmetry is broken. The calculation concerns in particular the phonon dispersion curves localized on the interface and step edge, and employs the matching procedure in the harmonic approximation. The nearest and next nearest neighbors elastic force constants between the mass sites in the model, as well as a modification of the elastic strain field induced by the presence of the step, are considered. Analytic expressions are obtained for the phonon dispersion relations of the localized surface and edge elastic waves and the bulk phonons near a step. The breakdown of translational symmetry perpendicular to the step edge gives rise to several Raleigh-like branches localized in the neighborhood of step and interface. The effects of varying the elastic force constants at an interface and the strain field parameter near the step are studied. These factors influence the number of localized modes as well as their frequency, intensity and attenuation.

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