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RF magnetron sputtering technique was employed to fabricate gallium zinc oxide ((Ga)ZnO) semiconductor thin film transistor (TFT) at 100°C. X-ray diffraction and Scanning electron microscopy were used to identify the structure and morphology of (Ga)ZnO layer. Self-heating effect was very much reduced when compared with output characteristics of a TFT fabricated using undoped zinc oxide. The low deposition and processing temperatures make (Ga)ZnO-TFTs very promising for the flexible electronics.

Thin film transistors (TFTs) were fabricated on a glass substrate using zinc oxide material as a channel layer. The layers were grown by radio frequency magnetron sputtering method at a temperature of 100°C. The output characteristics of a TFT device showed that there is a reduction in drain current at increased drain-source voltage and gate-source voltage. This evidenced the existence of self-heating effect which may be due to increased donor type point defects. The electrical characteristics of a device show an improved intrinsic channel mobility of 4 cm2/Vs, threshold voltage of 12 V, sub-threshold swing of 1 V/decade, and very much decreased off current of the order 10−12 A.

Europium-doped Gadolinia (Eu-Gd2O3) phosphor nanoparticles have been synthesized by a reverse microemulsion system using cyclohexane as the oil phase, a non-ionic surfactant Igepal CO 520 and the mixed aqueous solutions of gadolinium III nitrate hexahydrate and Europium III nitrate hexahydrate as the water phase. The synthesized and calcined powders were characterized by thermogravimetry-differential thermal analysis (TG-DTA), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR). The XRD results showed that the powders were cubic phase of Gd 2O3 after being calcined in the air at 1,000�C. DTA and FTIR also evidenced the formation of Gd2O3 at 1,000�C. SEM revealed that the particle size decrease with increase in Eu content. EDS confirmed the presence of Gd and Eu phase in the nanopowders calcined at 1,000�C. The photoluminescence studies indicated that a strong emission peak at 610nm is a characteristic red emission of Eu3+, and the emission intensity increases with increase in Eu content. � 2012 Copyright Taylor and Francis Group, LLC.

In order to experimentally check the Ni doped In2O3 as a potential spintronic material and to search for high temperature ferromagnetic material, a series of (In1-xNix) 2O3 (x=0.03, 0.05, and 0.07) nanoparticles were prepared by sol-gel method. Lattice parameter measurement shows distinct shrinkage of the lattice constant indicating the actual incorporation of Ni ions into the In2O3 lattice. X-ray diffraction (XRD) data show that all the samples exhibit single-phase polycrystalline behavior. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses show that the particle size of the calcined powder is in the range of 10-14nm and 8-9nm, respectively. SEM energy dispersive x-ray spectrometer (EDS) mapping shows the presence of Ni ions in the Ni doped In2O3 sample. High resolution transmission electron microscopy (HRTEM) micrographs show lattice fringes of 0.290 and 0.322nm corresponding to the crystallographic plane (222) and (310) of cubic In2O3. Magnetization study indicated that the Ni doped In2O3 samples exhibit diamagnetic behavior. Copyright � Taylor & Francis Group, LLC.

Gadolinium aluminate (GdAlO3) perovskite nanopowders were synthesized using microreactors made of poly(oxyethylene) nonylphenyl ether/water/cyclohexane microemulsions. Differential thermal analysis confirmed the formation of GdAlO3 at 902°C. X-ray diffraction analysis (XRD) of all the powders indicated the formation of single-phase perovskite structure on calcination. The average crystallite size was found to increase with increase in water-to-surfactant molar ratio and the average particle size increases from 23 to 28 nm on increasing the molar ratio from 4 to 8. The Fourier transform infrared (FTIR) spectra show that the lower frequency bands are assigned to M–O vibrations, which are characteristic vibrations of perovskite structure compounds.

Li doped SnO2 nanoparticles were synthesized using an emulsion precursor derived from a mixed-metal and oleic acid solution. The precursors and derived oxide powders were characterized by differential thermal analysis, thermogravimetric analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM), and Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). The XRD studies reveal that the material is assigned to be SnO2 tetragonal Cassiterite phase. The average particle size as determined from TEM varies in the range 12–181 nm. The amount of Li content in the sample determined by ICP-AES was found to 1.615 wt%.

Hexagonal γ-alumina (γ-Al2O3) platelets were prepared by combining sol–gel process and hydrothermal process. The starting material used for the preparation of alumina sol was aluminium-tri-isopropoxide. Alumina sol was subjected to hydrothermal treatment at a reaction temperature of 250°C for 12 h. X-ray diffraction (XRD) of as-synthesized powder confirms the formation of boehmite. The phase present in the powders calcined at 600°C and 800°C was γ-Al2O3. Scanning electron microscopy (SEM) micrographs revealed γ-alumina nanoplatelets had diameters ranging from 30 to 50 nm and lengths ranging from 60 to 90 nm. The transmission electron microscopy (TEM) analysis of the calcined powders at 800°C revealed the average particle size of γ-alumina nanoplatelets of 90 nm in length and 36 nm in diameter. The crystallinity of the γ-alumina nanoparticles were confirmed by selected area diffraction pattern and high resolution TEM.

Lanthanum Aluminate (LaAlO3) nanoparticles have been synthesized at low temperature using the sol–gel method, in combination with the self-propagating combustion technique, by adding a little stearic acid as dispersant during citric acid addition. Calcinated nano-LaAlO3 has been characterized using DTA-TGA, X-ray diffraction, infrared spectroscopy and transmission electron microscopy. X-ray diffraction studies confirm the formation of LaAlO3 at low temperature by adding stearic acid. FTIR analysis shows the characteristic bands at 660 and 449 cm−1 were those for LaAlO3. TEM micrographs showed an average particle size of ∼25 nm without stearic acid, which were in contrast to the highly agglomerated particle with stearic acid. The influence of the stearic acid on the morphology of nano-LaAlO3 was also discussed.

Nanocrystalline α-Al2O3 powders have been prepared by pyrolysis of a complex compound of aluminum with acetylacetone. The volumetric ratio (alumina to acetylacetone) of the starting feedstock has been shown to be a critical factor for the formation of nano α-Al2O3 powders. The optimum calcinations temperature of the precursor powder for crystallization of nano α-Al2O3 was found to be 1000°C for 2 h. Transmission electron microscopy (TEM) micrographs showed, the obtained materials could be modified from segregated nanoparticle to aggregates of nanoparticle with decrease in the volume ratio of alumina to acetylacetone from 8:2 to 5:5 in the precursor solutions. Fourier transform infrared spectra (FTIR) analysis show peak at 450 cm−1 corresponds to α-Al2O3 at 1000°C.

Nanosized alumina powders have been prepared via reverse micelle and sol-gel processing. By stepwise hydrolysis using aqueous ammonia as the precipitant, hydroxide precursor was obtained from nitrate solutions dispersed in the nanosized aqueous domains of microemulsion consisting of cyclohexane as the oil phase, poly(oxyethylene) nonylphenyl ether (Igepal CO-520) as the non-ionic surfactant, and an aqueous solution containing aluminium nitrate as the water phase. The synthesized and calcined powders were characterized by thermogravimetry-differential thermal analysis, transmission electron microscopy, and scanning electron microscopy. The XRD analysis showed that the complete transformation from γ -Al2O3 nanocrystalline to α-Al2O3 was observed at 1100°C. The resulting alumina nanopowder exhibits particle agglomerates of 135–200 nm in average diameter occur when they calcined at 1200°C. The average particle size was found to increase with increase in water to surfactant (R) molar ratio.

Al2O3-ZrO2 composite precursor powder containing 5–20 wt% ZrO2 was prepared by hydrothermal method at a reaction temperature of 190°C and pressure 4 kgf/cm2. X-ray diffraction (XRD) of as-synthesized powder confirms the formation of bayerite and boehmite. The phases present in the powders calcined at 500°C and 800°C are α-Al2O3 and t-ZrO2. The Frontier Transform Infrared (FTIR) studies revealed the formation of α-Al2O3 in corroboration with X-ray studies. The transmission electron microscopy (TEM) analysis of the calcined powders at 800°C revealed the average particle size of alumina platelets is 60–70 nm in diameter and 10–15 nm in thickness whereas zirconia is observed as clusters of size 10–20 nm. Energy Dispersive Spectroscopy (EDAX) confirms the presence of alumina and zirconia particles.

This article is focused on the preparation of barium titanate nanopowder/epoxy composites and studying the effect of barium titanate nanopowder on improving mechanical and thermal characteristics o...

Calcium oxide (CaO) doped Alumina–zirconia fibers were prepared by sol-gel process. The starting materials used for the preparation of alumina and zirconia sol were aluminium-tri-isopropoxide and zirconium oxychloride, respectively. Alumina sol and zirconia sol were mixed in definite proportions, so that the final composition contains 10 wt% ZrO2. CaO was introduced into the mixed sol in the form of calcium nitrate such that the final composition contains 1 and 2 wt%. Alumina–zirconia fibers were prepared from the mixed sol containing CaO, respectively. Sintered alumina–zirconia fiber has α -Al2O3, t-ZrO2, and m-ZrO2 phases. The phase transition to α -Al2O3 takes place at lower temperature in the presence of CaO. The addition of CaO increases the grain size.

Alumina and alumina-zirconia minispheres were prepared by sol-gel process. The starting materials used for the preparation of alumina and zirconia sol were aluminium-tri-isopropoxide and zirconium oxychloride, respectively. Alumina sol and zirconia sol were mixed in definite proportions, so that the final composition contained 5, 10, 15, and 20 wt.% ZrO 2. The sintering behavior of alumina and alumina-zirconia minispheres were studied by sintering at 1400, 1500, and 1600�C. X-ray diffraction analysis showed the presence of ? -Al 2O 3 in alumina minispheres and ? -Al 2O 3 and t-ZrO 2 in minispheres containing 5 wt.% ZrO 2 sintered at 1400�C. Monoclinic ZrO 2 was also present in the minispheres containing higher amounts of ZrO 2 and sintered at higher temperatures. Scanning electron microscopic observation revealed progressive densification with increasing sintering temperature and zirconia content. The density of the sintered spheres was found to be the highest for spheres containing 20 wt.% ZrO 2 sintered at 1600�C.