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حرية الوصول المقاله
1 - Influence of argon gas flow on mechanical and electrical properties of sputtered titanium nitride thin films
Kaykhosrow Khojier Hadi Savaloni Ebrahim Shokrai Zohreh Dehghani Naser Zare DehnaviAbstractTitanium nitrides have good mechanical, tribological, electrical, biomedical, and optical properties; therefore, they are used to harden and protect cutting and sliding surfaces, as semiconductor devices, and as a nontoxic exterior for biomedical applications. T أکثرAbstractTitanium nitrides have good mechanical, tribological, electrical, biomedical, and optical properties; therefore, they are used to harden and protect cutting and sliding surfaces, as semiconductor devices, and as a nontoxic exterior for biomedical applications. The dependence of the mechanical and electrical properties of titanium nitride thin films deposited on silicon substrates by direct-current reactive magnetron sputtering technique on argon gas flow (in the range of 8 to 20 sccm) was investigated. The crystallographic structure of the films was studied by X-ray diffraction (XRD), while surface morphology was studied using atomic force microscopy (AFM). Mechanical and electrical properties of these films were investigated by nanoindentation test and a four-point probe instrument, respectively. The XRD patterns showed titanium nitride (TiN) formation with a face-centered cubic structure for all samples. It was also observed that (111) crystallographic direction was the preferred orientation for TiN thin films which became more pronounced with increasing argon gas flow. The AFM images showed a granular structure for TiN layers. The hardness, crystallite/grain size (obtained from XRD and AFM), and surface roughness increased with the flow of argon gas, while elastic modulus and dislocation density in the films decreased. The study on electrical properties showed that the dependence of voltage with current for all samples was linear, and film resistivity was increased with argon gas flow. تفاصيل المقالة -
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2 - Temperature dependence of resistivity of RFeAsO compounds
S. Mukherjee Papri Dasgupta Asok Poddar Chandan MazumdarAbstractThe resistivity (ρ) data for RFeAsO compounds (R = Ce, Pr, Nd, Sm), in the temperature (T) range 35–315 K have been analyzed to identify the dominant scattering mechanisms. Close to the room temperature, the system appears to be a metal with low electron density أکثرAbstractThe resistivity (ρ) data for RFeAsO compounds (R = Ce, Pr, Nd, Sm), in the temperature (T) range 35–315 K have been analyzed to identify the dominant scattering mechanisms. Close to the room temperature, the system appears to be a metal with low electron density, and the electron–phonon scattering is the dominant one. At lower temperatures, electron–electron scattering plays an important role. In an intermediate temperature region, unlike metallic system, dρ/dT is negative; and ρ−1 varies as ln T as in a state of weak localization. We look into the origin of negative dρ/dT. The analysis of ρ(T) data below the SDW transition temperature shows the presence of electron–electron interaction in addition to a SDW energy gap, and also gives an estimate of the SDW energy gap. تفاصيل المقالة -
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3 - The effect of varying temperature and O2 flow rate in ex situ annealed tin-doped indium for fabrication of commercial grade indium tin oxide
M. R. Kiyani Y. S. JaliliAbstractIn this work, tin-doped indium was deposited on a glass substrate via the electron beam evaporation technique. Then, the as-grown thin films were baked in the presence of oxygen at different O2 flow rates and temperatures inside a furnace to obtain transparent c أکثرAbstractIn this work, tin-doped indium was deposited on a glass substrate via the electron beam evaporation technique. Then, the as-grown thin films were baked in the presence of oxygen at different O2 flow rates and temperatures inside a furnace to obtain transparent conducting oxide thin film structures. The electrical and optical properties of the layers were investigated, the thickness of all samples was kept at 500 nm and the rate of deposition was set at 0.1 nm min−1. The best optical and electrical properties were obtained at O2 flow rate of 1.5 Nl min−1 and temperatures of 500 °C where above 90 % optical transparency and ≤4 × 10−3ohm cm−1 electrical resistivity were achieved. تفاصيل المقالة -
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4 - Effect of substrate temperature on ZnS films prepared by thermal evaporation technique
Rahul VishwakarmaAbstractThe nanocrystalline ZnS semiconducting thin films of 500 nm thickness have been deposited on glass substrate at different substrate temperatures (Ts) by thermal evaporation technique. The structural property of deposited thin films has been measured by X-ray dif أکثرAbstractThe nanocrystalline ZnS semiconducting thin films of 500 nm thickness have been deposited on glass substrate at different substrate temperatures (Ts) by thermal evaporation technique. The structural property of deposited thin films has been measured by X-ray diffraction, scanning electron microscopy, and Energy dispersive analysis of X-ray. The electrical and optical properties of thin films have been determined by D.C. two point probe and ultra-violet visible spectroscopy measurements. The X-ray diffraction patterns show that thin films have cubic structure. The electrical resistivity of thin films has decreased from 0.36 × 106 to 0.15 × 106 Ω cm as substrate temperature increases from 300 to 400 K. It shows that films have semiconducting in nature. The grain size and electrical conductivity of the thin films have increased as the deposition temperature increased while dislocation density, activation energy, and band gap decreased. The minimum band gap 3.43 eV has been found. تفاصيل المقالة -
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5 - Effect of indium substitution on the electrical and magnetic properties of Ni–Zn ferrite
B. B. V. S. Vara PrasadAbstractIndium-substituted polycrystalline nickel zinc ferrites of different compositions Ni0.65Zn0.35Fe2−xInxO4 (x = 0.00, 0.04, 0.08, 0.12, 0.16, 0.2) have been prepared by solid-state reaction route. Calcination and sintering of all samples were done in air atmospher أکثرAbstractIndium-substituted polycrystalline nickel zinc ferrites of different compositions Ni0.65Zn0.35Fe2−xInxO4 (x = 0.00, 0.04, 0.08, 0.12, 0.16, 0.2) have been prepared by solid-state reaction route. Calcination and sintering of all samples were done in air atmosphere at 950 °C and 1250 °C, respectively, followed by natural cooling to room temperature. Characterization of the basic composition was done by X-ray diffractometry, saturation magnetization and Curie temperature. The effect of incorporation of larger indium ions in place of iron was studied with the help of saturation magnetization, Curie temperature, permeability, magnetic loss factor, DC electrical resistivity and dielectric properties. The highest magnetization and permeability values of the present system under study are 74.1 emu/g and 438 for the basic composition (concentration x = 0). The DC electrical resistivity was found to decrease up to x = 0.3 and increase thereafter. The variation in the electric and magnetic properties of this ferrite system is dominated by the decrease in iron concentration. Characteristic high dielectric constant values were recorded for these bulk ceramic materials. تفاصيل المقالة -
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6 - Synthesis and Ethanol Sensitivities of Sn02 nanowires Suvit
. Thanasanvorakun Pongsri Mangkomtong Majid Monajjemi Nikom SangkorntongSn02 nanowires with diameters of 30 — 200 nm have been synthesized by using carbothermalprocess via a thick film of tin dioxide and carbon powder precursor. The nanowires werecharacterized by X-ray power diffraction (XRD), scanning electron microscopy (SEM),transm أکثرSn02 nanowires with diameters of 30 — 200 nm have been synthesized by using carbothermalprocess via a thick film of tin dioxide and carbon powder precursor. The nanowires werecharacterized by X-ray power diffraction (XRD), scanning electron microscopy (SEM),transmission electron microscopy (TEM) and Selected Area Electron Diffraction (SAED).The gas sensing characteristic of nanowires toward ethanol vapor was investigated. The gassensitivity experiments have demonstrated that the as-synthesized Sn02 materials exhibitgood sensitivity to ethanol vapors, which may offer potential applications in gas sensors. Thedetails of its sensing characteristics were observed and discussed. تفاصيل المقالة -
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7 - Cadmium Oxide Thin Films Deposited by a Simplified Spray Pyrolysis Technique for Optoelectronic Applications
K. Usharani A.R. Balu M. Suganya V.S. NagarethinamCadmium oxide thin films were fabricated on glass substrates by a simplified and low cost spray pyrolysis technique at different substrate temperatures. The X-ray diffraction study showed that irrespective of substrate temperature all the films exhibits a preferential أکثرCadmium oxide thin films were fabricated on glass substrates by a simplified and low cost spray pyrolysis technique at different substrate temperatures. The X-ray diffraction study showed that irrespective of substrate temperature all the films exhibits a preferential orientation along the (1 1 1) plane. The values of crystallite size were found to be in the range 20.72 – 29.6 nm. The percentage transmittance and the optical band gap values are found to be in the range of 78 – 89 % and 2.38 – 2.55 eV respectively. The optical transmittance is found to increase gradually with increase in substrate temperature. Urbach energy decreases with increase in substrate temperature. Optical parameters such as refractive index and packing density were calculated. The dispersion parameters of the as-deposited CdO films were calculated to analyze their choice in designing optical devices. PL studies confirm that the films exhibit strong luminescent properties. The value of ρ decreases with increase in substrate temperature and attains a minimum value of 0.26x 10-6 ohm-m for the film coated at 375ºC which has the least thickness. تفاصيل المقالة -
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8 - Fabrication of Silver doped Buckypaper and Investigation of its Properties
Yoan Zhi Silvia TokomatovMicrowave absorbing property of composites containing Ag nanoparticles filled multiwalled carbon nanotube buckypaper (Ag-BP) has been investigated. Buckypaper doped with silver was prepared by direct dispersion and filtration method. From the low temperature resistivity أکثرMicrowave absorbing property of composites containing Ag nanoparticles filled multiwalled carbon nanotube buckypaper (Ag-BP) has been investigated. Buckypaper doped with silver was prepared by direct dispersion and filtration method. From the low temperature resistivity measurement it was found that increasing doping level decreases the electrical conductivity of the buckypaper. 30 wt. % and 40 wt. % of Ag-BP samples shows the maximum transmission coefficient, with very high conductivity. The results demonstrate that microwave absorption of Ag-BP was attributed only due to the dielectric loss rather than other losses.The absorption peak frequency of the Ag/MWCNTs BP can be controlled easily in the presence of Ag nanoparticles into the CNT mats. تفاصيل المقالة
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