scholarly journals Influence of L-Tryptophan on Growth and Optical Properties of PbS Nanocrystalline Thin Films

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
R. Palomino Merino ◽  
R. Gutiérrez Pérez ◽  
P. Trejo García ◽  
L. Chaltel Lima ◽  
O. Portillo Moreno ◽  
...  
Keyword(s):  
Thin Films ◽  
Morphological Changes ◽  
Band Gap Energy ◽  
Undoped Sample ◽  
Cubic Phase ◽  
Electronic Charge ◽  
Absorption Bands ◽  
Scherrer Formula ◽  
Xrd Patterns ◽  
Nanocrystalline Thin Films

The growth through the green chemical bath of PbS doped systematically with the biomolecule L-tryptophan led to growth of hybrid, inorganic-organic, nanocrystalline thin films onto glass slides at T~80°C. The thickness was found in the range of 230–140 nm. Morphological changes were analyzed using atomic force microscopy (AFM). FTIR (Fourier-transform infrared spectroscopy) spectra showed broad absorption bands located at ~3450 cm−1 attributed to stretching of the H2O molecules and two small absorption bands located at ~2285 cm−1 and ~2918 cm−1 along with a strong band at ~1385 cm−1 assigned to vibration modes corresponding to CO32− ions. In the patterns of X-ray diffraction (XRD), the cubic phase was identified in all the samples according to the angular positions 2θ~26.08°, 30.13°, 43.08°, 51.91°, 53.60°, 6251°, 68.98°, and 71.15°. Using the Scherrer formula on the XRD patterns, the grain size (GS) was determined; for the undoped sample, ~42 nm was found, whereas for the doped samples, ~42–22 nm was found. The electronic charge distribution of L-tryptophan was determined using the molecular electrostatic potential (MEP) to understand the decrease on the GS associated with the interaction of π electrons from conjugated rings and amino-acid functional groups. The absorbance spectra in doped films showed excitonic peaks at ~1.8–2.1 eV associated to a higher energy of the 1Sh → 1Sh and 1Ph → 1Pe electronic transitions. Through optical absorption, a shift for the band gap energy was observed from ~1.4 eV for the undoped sample and ~2.1–2.3 eV for the doped films, respectively. Such behaviour is generally associated with the GS decrease and the effect of quantum confinement; a simple model by calculating changes in Gibbs free energy (ΔG°) for growth of nanocrystals is presented.

Nanocrystalline CdSe Thin Films of Different Morphologies in Thermal Evaporation Process

2008 ◽  
Vol 8 (12) ◽  
pp. 6474-6480 ◽  
Author(s):  
U. Pal ◽  
M. Herrera Zaldivar ◽  
R. Sathyamoorthy ◽  
V. Manjuladevi ◽  
P. Sudhagar ◽  
...  
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Quantum Confinement Effect ◽  
Band Gap Energy ◽  
Morphological Variations ◽  
Glass Substrates ◽  
Interface Strain ◽  
Average Size ◽  
Film Interface ◽  
Nanocrystalline Thin Films

Cadmium selenide nanocrystalline thin films of quasi-spherical morphology are prepared by evaporating CdSe nanopowders on glass substrates. Slightly oval shaped CdSe particles of about 165 nm average size (in 2-D) could be assembled over glass substrates by controlling the film thickness. Morphologies like assembly of particles, interconnected particles with mosaic-like structures and thin films of smooth surfaces could be prepared simply by controlling film thickness. A mechanism for such morphological variations is proposed. Observed variation of band gap energy in the films is explained in terms of quantum confinement effect and substrate-film interface strain.

scholarly journals Structural and Surface Morphology Studies of La0.67Ba0.33(Mn1−xAlx)O3Thin Films Prepared by Sol-Gel Method

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
H. Abdullah ◽  
M. S. Zulfakar
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Sol Gel ◽  
Rhombohedral Structure ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Xrd Patterns ◽  
Nanocrystalline Thin Films ◽  
Prominent Peak

Nanocrystalline thin films of La0.67Ba0.33(Mn1−xAlx)O3(x=0.00,0.05,0.10, and 0.15) were prepared by sol-gel method, as a starter material consisting of La2O3, BaNO3, Mn(NO3), and Al(NO3). The molarities of La2O3and BaNO3are constant, while molarities of Mn(NO3) and Al(NO3) were calculated based on stoichiometric theory. Thin films were deposited on quartz glass substrate by using spin coating technique and sintered at 700°C. X-ray diffractometer (XRD) patterns showed that these thin films consist of pure La0.67Ba0.33(Mn1−xAlx)O3phase where the most prominent peak is observed at (104). All the samples display a rhombohedral structure. Scanning electron microscopy (SEM) showed that aggregation of small particles occurred more in doped films than in undoped films. The surface morphology has been studied by using AFM, and the roughness of thin films was analyzed.

FTIR and VSM properties of samarium-doped nickel ferrite

2014 ◽  
Vol 07 (04) ◽  
pp. 1450046 ◽  
Author(s):  
İsrafil Şabikoğlu ◽  
Levent Paralı
Keyword(s):  
Saturation Magnetization ◽  
Nickel Ferrite ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
Conventional Solid State Reaction ◽  
Average Grain Size ◽  
Structure Surface ◽  
Coercivity Field ◽  
Xrd Patterns

Nickel Ferrite ( NiFe 2 O 4) doped with Samarium (Sm) (0.2, 0.3, 0.4, 0.5 mol.%) was prepared by the conventional solid-state reaction. The crystal structure, surface morphology, infrared spectrum of absorption, and magnetic properties of samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and vibrating sample magnetometer (VSM). XRD patterns were indexed with inverse spinel cubic phase with the space group of Fd-3m of nickel ferrite. The average grain size was about 5–10 μm. FTIR spectral study on the NiFe 2 O 4 ferrite phase was recorded between 350 cm-1 and 4000 cm-1. Two fundamental absorption bands of the ferrites were appeared at 450 cm-1 and 1000 cm-1 characteristic of metal vibrations. VSM measurements show that the NiFe 2 O 4 doped with Sm 0.3% has the highest value of saturation magnetization. It is also easily demagnetized due to the low value of coercivity field it has. Both NiFe 2 O 4 doped with Sm 0.2 mol.% and 0.4 mol.% materials have same values of coercivity field. However, NiFe 2 O 4 doped with Sm 0.4 mol.% material has the comparatively high value of saturation magnetization than NiFe 2 O 4 doped with Sm 0.2%, also this material was hardly demagnetized, and has highest coercivity field.

Structure and Optical Properties of Al1−xScxN Thin Films

2013 ◽  
Vol 537 ◽  
pp. 140-143 ◽  
Author(s):  
Jing Yang ◽  
Miao Miao Cao ◽  
Yu Dong Li ◽  
Yi Gang Chen
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Grain Size ◽  
Optical Properties ◽  
Band Gap Energy ◽  
Wave Number ◽  
Gap Energy ◽  
Aln Film ◽  
Dc Magnetron Reactive Sputtering ◽  
Xrd Patterns

In this study, c-axis oriented AlN and Al1−xScxN films have been successfully grown on Si (100) and quartz glass by DC magnetron reactive sputtering method. The XRD patterns show that the crystal structure of the Al1−xScxN films is (002) orientation. The grain size and band gap energy (Eg) of the Al1−xScxN films decrease as the Sc concentration increases. The frequency of the E2 (high) mode observed in the Al1−xScxN films shows higher red shift compared to that observed in AlN film and the peak shifts to the low wave number with the increasing of Sc concentration.

Thermally Deposited Sb2S3: Bi Thin Films for Solar Cell Absorber

2018 ◽  
Vol 21 (1) ◽  
pp. 037-042
Author(s):  
Durai Chella Priya ◽  
Daniel Thanabalan ◽  
Johnson Henry ◽  
Kannusamy Mohanraj ◽  
Ganesan Sivakumar ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Evaporation ◽  
Visible Region ◽  
Band Gap Energy ◽  
Spectroscopic Techniques ◽  
Orthorhombic Crystal ◽  
Thermal Evaporation Method ◽  
Strong Emission ◽  
Uv Visible ◽  
Xrd Patterns

In recent years there has been growing interest in the materials suitable for real time storage application. Sb2S3 is a prospective material in this regard due to good photoconductivity. In this contest, thin films of Sb2S3 and Bi3+ doped Sb2S3 were deposited onto the transparent glass substrate by thermal evaporation method. The structural, optical and electrical properties were investigated by XRD, UV-Visible, Photoluminescence, and Impedance spectroscopic techniques. The XRD patterns confirm the orthorhombic crystal structured Sb2S3 and the inclusion of Bi3+ ions in the crystal system. UV-Visible analysis exhibited wide optical absorption in the visible region for both Sb2S3 and Bi3+ doped films and their band gap energy was found to be 1.60 eV and 1.55 eV respectively. The photoluminescence spectra showed a strong emission at 361nm. The value of capacitance, dielectric constant and real part of impedance decreases with increasing frequency for both the samples.

AN INVESTIGATION INTO THE FABRICATION AND ELECTRICAL PROPERTIES OF Ni–Al INTERMETALLIC COMPOUND THIN FILMS

2008 ◽  
Vol 22 (07) ◽  
pp. 877-888
Author(s):  
JICHENG ZHOU ◽  
JINBO ZHU ◽  
JIANWU YAN
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Conduction Mechanism ◽  
Positive Temperature Coefficient ◽  
Root Mean Square Roughness ◽  
Positive Temperature ◽  
Alloy Films ◽  
Atomic Force ◽  
Xrd Patterns ◽  
Nanocrystalline Thin Films

Ni – Al intermetallic compounds nanocrystalline thin films were deposited by direct current magnetron co-sputtering from elemental Ni and Al targets. The integrity of the thin films and their elemental compositions were assessed using a scanning electron microscope (SEM) equipped with an energy dispersive spectroscope analyzer. The morphologies of thin alloy films are density and smoothing characterized by atomic force microscope and SEM. The preferred (111) orientation in both as-deposited and annealed films are identified using X-ray diffractometer (XRD). The electrical properties of the alloy films were studied, and show good metallic conduction characteristics. From room temperature to 200°C, the resistance of the thin films are assumed to be linear as a function of varying temperature. All the thin films show a positive temperature coefficient of resistance (TCR). As 1% O 2 was introduced into the vacuum chamber during sputtering, the root mean square roughness of the films increased, grain size turned out to be smaller, and the crystallization process was blocked. The amorphous Al 2 O 3 phase was found in XRD patterns. The results of TCR measurement show a different electric conduction mechanism compared with alloy films.

scholarly journals Chemical Bath Deposition of PbS:Hg2+Nanocrystalline Thin Films

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
R. Palomino-Merino ◽  
O. Portillo-Moreno ◽  
L. A. Chaltel-Lima ◽  
R. Gutiérrez Pérez ◽  
M. de Icaza-Herrera ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Bath Deposition ◽  
Morphological Changes ◽  
X Rays ◽  
Structural And Optical Properties ◽  
Glass Substrates ◽  
Zinc Blende ◽  
20 Nm ◽  
Nanocrystalline Thin Films

Nanocrystalline PbS thin films were prepared by Chemical Bath Deposition (CBD) at 40 ± 2°C onto glass substrates and their structural and optical properties modified by in-situ doping with Hg. The morphological changes of the layers were analyzed using SEM and the X-rays spectra showing growth on the zinc blende (ZB) face. The grain size determined by using X-rays spectra for undoped samples was found to be~36 nm, whereas with the doped sample was 32–20 nm. Optical absorption spectra were used to calculate theEg, showing a shift in the range 1.4–2.4 eV. Raman spectroscopy exhibited an absorption band~135 cm−1displaying only a PbS ZB structure.

scholarly journals Effect of Selective Lateral Chromium Doping by RF Magnetron Sputtering on the Structural, and Opto-Electrical Properties of Nickel Oxide

2021 ◽  
Vol 11 (23) ◽  
pp. 11546
Author(s):  
Mohammad Shah Jamal ◽  
Khan Sobayel ◽  
Halina Misran ◽  
Taskina Nasrin ◽  
Khaled Althubeiti ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Magnetron Sputtering ◽  
Nickel Oxide ◽  
Rf Magnetron Sputtering ◽  
Effect Study ◽  
Diffraction Peak ◽  
Cubic Phase ◽  
As Doping ◽  
Xrd Patterns

In this study, chromium (Cr)-doped nickel oxide (NiO) thin films were deposited by employing selective lateral doping of Cr in NiO by radio-frequency magnetron sputtering at different doping times ranging from 0 s (undoped) to 80 s. The structural, optical, and electrical properties of the resulting Cr-doped NiO thin films were investigated. Structural investigation from XRD patterns indicated that the grown Cr-doped NiO layer crystallized in a cubic phase. Broadening of the diffraction peak with increasing doping time from 0 s to 80 s led to a reduction in the crystallite size that varied from 23.52 nm to 14.65 nm. Compared with the undoped NiO, the diffraction peak along the (200) plane shifted from left to right as a function of doping time. This result indicated that Cr+3 could easily enter the NiO lattice. Results from the Hall-effect study disclosed that electrical properties of Cr-doped NiO was highly dependent on doping time. The conductivity of NiO was increased with doping time, and the highest conductivity (8.73 × 10−2 Scm−1) was achieved at a doping time of 80 s. Finally, optical investigations revealed that as doping time increased, the optical bandgap of Cr-doped NiO films dropped from 3.43 eV to 3.28 eV. The highest Urbach energy at higher doping time indicated that crystallinity became poorer, and the degree of defects increased with increasing doping time.

scholarly journals CATHODIC ELECTRODEPOSITION OF Cu 4 SnS 4 THIN FILMS FROM ACIDIC SOLUTION

2017 ◽  
Vol 26 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Anuar Kassim ◽  
Ho Soon Min ◽  
Zulkefly Kuang ◽  
Tan Wee Tee ◽  
Abdul Halim Abdullah ◽  
...  
Keyword(s):  
Thin Films ◽  
Sodium Thiosulfate ◽  
Deposition Potential ◽  
Band Gap Energy ◽  
Tin Sulfide ◽  
Cathodic Electrodeposition ◽  
Glass Substrates ◽  
Tin Chloride ◽  
Ito Glass ◽  
Xrd Patterns

In this work the synthesis of copper tin sulfide thin films by electrodeposition is carried out. The films were deposited onto ITO glass substrates from an aqueous solution bath containing copper sulfate, tin chloride and sodium thiosulfate at pH 1 and room temperature. Prior to the deposition, a cyclic voltammetry experiment was carried out  between two potential limits (+1000 to -1000 mV versus Ag/AgCl) to probe the effect of  the applied potential and to determine the most likely suitable electrodeposition potential  for the deposition of copper tin sulfide. The deposition was attempted at various cathodic potentials such as -400, -600, -800, -1000 mV to determine the optimum deposition  potential. The films have been characterized by techniques such as optical absorption, Xray diffraction  and  atomic  force  microscopy. The XRD patterns show that the films are polycrystalline with orthorhombic structure. The AFM studies reveal the electrodeposited films were smooth, compact and uniform at deposition potentials of –600 mV versus  Ag/AgCl. The direct optical band-gap energy was obtained to be 1.58 eV.   

Infrared Intensity Measurements of Cryodeposited Thin Films of NH3, NH4HS, H2S, and Assignments of Absorption Bands

1980 ◽  
Vol 34 (5) ◽  
pp. 525-533 ◽  
Author(s):  
John R. Ferraro ◽  
G. Sill ◽  
U. Fink
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Metastable Phase ◽  
Cubic Phase ◽  
Spectral Transmission ◽  
Absorption Bands ◽  
Intensity Measurements ◽  
Infrared Spectral ◽  
Infrared Intensity ◽  
Transmission Measurements

Interferometric infrared spectral transmission measurements from 60 to 10 000 cm−1 were made for thin films of NH3, NH4HS, and H2S cryodeposits, and recorded as a function of thickness and temperature from 88 K to evaporation points. Integrated band intensities were measured and are reported for all major absorptions. Assignments for lattice and internal fundamental modes are discussed. Particular attention is devoted to the various reported phases of solid NH3, and it is concluded that three phases are supported by experimental evidence: the stable cubic phase, a low temperature amorphous phase, and an intermediate temperature metastable phase. Results and changes of the spectra as a function of temperature will be summarized. Intercomparisons of the spectra obtained for the three cryodeposits are made.

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