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1

Electrical and optical studies on thin films of indium phthalocyanine chloride

100%

Mammen S. , Menon C. S. , Unnikrishnan N. V.

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tom Vol. 23, No. 3

707--713

EN

Vacuum evaporated thin films of indium phthalocyanine chloride are prepared at room temperature. Post evaporation annealing is done at temperatures of 353 K, 403 K, 453 K and 503 K. The electrical conductivity and optical absorption spectra of these films are studied. From the optical absorption spectra, over a wavelength range of 200-900nm, the optical energy band gap Eg is calculated. A decrease in Eg is observed with an increase of annealing temperature. The thermal activation energy, Ea, is not notably affected by annealing. It is found that Ea is varied with a change in thickness of the film

2

Optimization of S:Sn precursor molar concentration on the physical properties of spray deposited single phase Sn2S3 thin films

100%

Srivind J. , Nagarethinam V. S. , Balu A. R.

Materials Science Poland

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2016

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tom Vol. 34, No. 2

393--398

EN

Nanoneedle structured Sn2S3 thin films were prepared by spray pyrolysis technique from aqueous solutions of tin (II) chloride and thiourea, keeping the molar concentrations of S:Sn = 0.01:0.01, 0.02:0.02, 0.03:0.03 and 0.04:0.04 in the starting solutions. XRD studies reveal that all the films exhibit orthorhombic crystal structure with a preferential orientation along the [2 1 1] direction. The peak intensity of the (2 1 1) plane is found to be maximum for the film coated with 0.02:0.02 S:Sn molar concentration which confirms the improved crystalline nature of this film. SEM images depict that the film coated with S:Sn molar concentration 0.02:0.02 exhibit needle shaped grains. The optical band gap exhibits red shift from 2.12 eV to 2.02 eV with an increase in S:Sn precursor molar concentration. Electrical studies show that the films having S:Sn molar concentrations 0.01:0.01 and 0.02:0.02 exhibit minimum resistivity values of 0.238 and 0.359Ω ·cm, respectively.

3

Determination of optical constants and thickness of amorphous GaP thin film

100%

Pimpabute N. , Burinprakhon T. , Somkhunthot W.

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2011

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tom Vol. 41, nr 1

257--268

EN

Gallium phosphide (GaP) thin film was prepared by an asymmetric bipolar pulsed-dc magnetron sputtering technique onto glass substrate at room temperature in an Ar atmosphere. A compacted GaP powder was used as a target. The X-ray diffraction patterns show that the film is amorphous. The transmittance of the film was measured in the incident photon wavelength range of 300–2000 nm. The film’s refractive index, thickness and absorption coefficient as a function of wavelength were determined by using Swanepoel’s method. The deduced absorption data indicate that the optical transition in the film is dominated by the indirect type. The corresponding energy of 1.51 eV was obtained for the 563š16 nm thin film.

4

Substitutional effect of copper on the cation distribution in cobalt chromium ferrites and their structural and magnetic properties

100%

Zeeshan T. , Anjum S. , Iqbal H. , Zia R.

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tom Vol. 36, No. 2

255-263

EN

A series of copper substituted cobalt chromium ferrites, CuxCo1 - xCr0.5Fe1.5O4 (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) has been synthesized, by employing powder metallurgy method. Calcination of the samples has been carried out for 24 hours at 1100 °C. The resultant materials have been investigated by using a variety of techniques, including X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM)), scanning electron microscopy (SEM), and ultraviolet visible spectroscopy (UV-Vis). The XRD patterns confirmed that all compositions had a cubic spinel structure with a single phase and the lattice parameter was found to increase with increasing copper concentration. FT-IR spectroscopy has been used for studying the chemical bonds in the spinel ferrite. Shifting of the bands ν1 and ν2 has been observed. It has been revealed from VSM analysis that saturation magnetization and coercivity decrease with rising the Cu+2 doping. Magnetic properties have been explained on the basis of cation distribution. Scanning electron microscopy (SEM) has been used to study the surface morphology of prepared samples. UV-Vis analysis revealed the optical absorption of the samples. An increase in band gaps has been observed with increasing copper concentration in the sample.

5

Modification in surface properties of poly-allyl-diglycol-carbonate (CR-39) implanted by Au+ ions at different fluences

88%

Sagheer R. , Rafique M. S. , Saleemi F. , Arif S. , Naab F. , Toader O. , Mahmood A. , Rashid R. , Hussain I.

Materials Science Poland

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2016

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tom Vol. 34, No. 2

468--478

EN

Ion implantation has a potential to modify the surface properties and to produce thin conductive layers in insulating polymers. For this purpose, poly-allyl-diglycol-carbonate (CR-39) was implanted by 400 keV Au+ ions with ion fluences ranging from 5 × 1013 ions/cm2 to 5 × 1015 ions/cm2. The chemical, morphological and optical properties of implanted CR-39 were analyzed using Raman, Fourier transform infrared (FT-IR) spectroscopy, atomic force microscopy (AFM) and UV-Vis spectroscopy. The electrical conductivity of implanted samples was determined through four-point probe technique. Raman spectroscopy revealed the formation of carbonaceous structures in the implanted layer of CR-39. From FT-IR spectroscopy analysis, changes in functional groups of CR-39 after ion implantation were observed. AFM studies revealed that morphology and surface roughness of implanted samples depend on the fluence of Au ions. The optical band gap of implanted samples decreased from 3.15 eV (for pristine) to 1.05 eV (for sample implanted at 5 × 1015 ions/cm2). The electrical conductivity was observed to increase with the ion fluence. It is suggested that due to an increase in ion fluence, the carbonaceous structures formed in the implanted region are responsible for the increase in electrical conductivity.

6

Effect of thermal annealing on structural and optical properties of In doped Ge-Se-Te chalcogenide thin films

88%

Singh P. K. , Tripathi S. K. , Dwivedi D. K.

Materials Science Poland

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2019

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tom Vol. 37, No. 4

554--562

EN

Thin films of Ge10–xSe60Te30Inx (x = 0, 2, 4 and 6) were developed by thermal evaporation technique. The annealing effect on the structural properties of Ge10–xSe60Te30Inx (x = 0, 2, 4 and 6) films has been studied by X-ray diffraction (XRD). The XRD results indicate amorphous nature of the as-prepared films whereas crystalline phases in annealed films were identified. Structural parameters such as average crystallite size, strain, and dislocation were determined for different annealing temperatures. Effect of annealing on optical constants of prepared films has been explored using UV-Vis spectrophotometer in the wavelength range of 400 nm to 1000 nm. Various optical constants were determined depending on annealing temperature. It has been noticed that the film transparency and optical bandgap Eg have been reduced whereas the absorption coefficient α and extinction coefficient k increased with increasing annealing temperature. It was found that the prepared samples obey the allowed direct transition. The reduction in optical bandgap with annealing temperature has been described by Mott and Davis model. Due to annealing dependence of the optical parameters, the investigated material could be utilized for phase change memory devices.

7

Structural optical and magnetic properties of transition metal doped ZnO magnetic nanoparticles synthesized by sol-gel auto-combustion method

88%

Sarfraz M. , Ahmed N. , Khizar-ul-Haq , Shahida S. , Khan M. A.

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tom Vol. 37, No. 2

280--288

EN

Transition metals, such as chromium (Cr) and manganese (Mn) doped zinc oxide (ZnO) magnetic nanoparticles, were synthesized via sole gel auto-combustion method. The prepared magnetic (Zn1−(x+y)MnxCryO, where x, y = 0, 0.02, 0.075) nanoparticles were calcined in an oven at 6000 °C for 2 hours. The morphologies of the nanoparticles were investigated using different techniques. X-ray diffraction (XRD) analysis revealed that the hexagonal wurtzite structure of the synthesized nanoparticles was unaffected by doping concentration. The crystallite size measured by Scherrer formula was in the range of 32 nm to 38 nm at different doping concentrations. Nanosized particles with well-defined boundaries were observed using a field emission scanning electron microscopy (FE-SEM). Fourier transform infrared (FT-IR) spectra showed a wide absorption band around 1589 cm−1 in all the samples, corresponding to the stretching vibration of zinc and oxygen Zn–O bond. A blue shift in optical band gaps from 3.20 eV for ZnO to 3.08 eV for Zn0.85Mn0.75Cr0.75 O nanoparticles was observed in diffuse reflectance spectra, which was attributed to the sp-d exchange interactions. The field-dependent magnetization M-H loops were measured using vibrating sample magnetometer (VSM). The VSM results revealed diamagnetic behavior of the ZnO nanoparticles which changed into ferromagnetic, depending on the doping concentration and particle size. The compositions of Zn, Cr, Mn and O in the prepared samples were confirmed by using the energy dispersive X-ray spectroscopy (EDX). Our results provided an interesting route to improve magnetic properties of ZnO nanoparticles, which may get significant attention for the fabrication of magnetic semiconductors.

8

Temperature Effect on the Growth Rate and Physical Characteristics of SnO2 Thin Films Grown by Atomic Layer Deposition

75%

Kim D. , Kim D. H. , Riu D.-H. , Choi B. J.

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nr 2

9

Effect of deposition temperature on structural, optical and electrical properties of copper bismuth sulphide (CuBiS2) thin films deposited by chemical bath deposition

75%

Balasubramanian V. , Kumar P. N. , Sengottaiyan D.

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tom Vol. 35, No. 2

329--334

EN

The effect of deposition temperature on the structural, optical and electrical properties of copper bismuth sulphide (CuBiS2) thin films deposited by chemical bath deposition onto glass substrates at different deposition temperatures (40 °C, 50 °C, 60 °C and 70 °C) for 5 hours deposition time period was investigated. The obtained films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX) and optical absorption spectra. All deposited films were polycrystalline and had an orthorhombic structure. Their grain size had changed with deposition temperature and their compositions were nearly stoichiometric. The optical band gap value was decreased from 2.44 eV to 2.33 eV with increasing the film thickness. Electrical parameters such as mobility and type of electrical conduction were determined from the Hall effect measurements. They showed that the obtained films have n-type conductivity and mobility values of the copper bismuth sulphide (CuBiS2) films have changed with deposition temperature.