Facile Preparation of Nanocrystalline ZnO Powder for Non-Volatile Memory Application

2014 ◽  
Vol 807 ◽  
pp. 151-160
Author(s):  
A. Kathalingam ◽  
Hyun Chang Park ◽  
Sam Dong Kim ◽  
Hyun Seok Kim ◽  
T. Mahalingam
Keyword(s):  
Solution Method ◽  
Zinc Nitrate ◽  
Zno Nanoparticle ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Transmission Electron ◽  
Non Volatile Memory ◽  
Effects Of Temperature ◽  
Volatile Memory ◽  
Zno Powder

In this work, synthesis of ZnO nanoparticle by solution method and its application in non-volatile memory is reported. Nanocrystalline ZnO particles were prepared by a novel chemical route using the combination of zinc nitrate [Zn (NO3)2 6H2O] and sodium hydroxide [NaOH] at low temperature. The effects of temperature and bath concentration for the synthesis of ZnO powder have been studied. Synthesized powder was characterized by X-ray diffraction (XRD), UV-Vis spectrometer, transmission electron microscopy (TEM) and photoluminescence. Using the prepared ZnO nanoparticles with organic PMMA; non-volatile memory cells were prepared and studied its switching property.

Polyaniline/SnO2 Nanocomposite Sensor for NO2 Gas Sensing at Low Operating Temperature

2015 ◽  
Vol 14 (04) ◽  
pp. 1550011 ◽  
Author(s):  
A. Sharma ◽  
M. Tomar ◽  
V. Gupta ◽  
A. Badola ◽  
N. Goswami
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Sensing Properties ◽  
Response Recovery ◽  
Transmission Electron ◽  
Gas Sensing Properties

In this paper gas sensing properties of 0.5–3% polyaniline (PAni) doped SnO 2 thin films sensors prepared by chemical route have been studied towards the trace level detection of NO 2 gas. The structural, optical and surface morphological properties of the PAni doped SnO 2 thin films were investigated by performing X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Raman spectroscopy measurements. A good correlation has been identified between the microstructural and gas sensing properties of these prepared sensors. Out of these films, 1% PAni doped SnO 2 sensor showed high sensitivity towards NO 2 gas along with a sensitivity of 3.01 × 102 at 40°C for 10 ppm of gas. On exposure to NO 2 gas, resistance of all sensors increased to a large extent, even greater than three orders of magnitude. These changes in resistance upon removal of NO 2 gas are found to be reversible in nature and the prepared composite film sensors showed good sensitivity with relatively faster response/recovery speeds.

Low-Temperature Synthesis of Nano-Crystalline ZnTiO3 Powders by Aqueous Sol-Gel Process

2014 ◽  
Vol 543-547 ◽  
pp. 3741-3744
Author(s):  
Quan Jing Mei ◽  
Cong Ying Li ◽  
Jing Dong Guo ◽  
Gui Wang ◽  
Hai Tao Wu
Keyword(s):  
Sol Gel ◽  
Zinc Nitrate ◽  
X Ray Diffraction ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Calcination Process ◽  
X Ray ◽  
Nano Crystalline ◽  
Transmission Electron ◽  
Sol Gel Process

The ecandrewsite-type ZnTiO3was successfully synthesized by the aqueous sol-gel method using TiO2dioxide and zinc nitrate as starting materials instead of expensive organic solvent and metal alkoxides. The as-prepared nanopowders were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA) and transmission electron microscopy (TEM), respectively. The results showed that the calcination process of gel consisted of a series of oxidation and combustion reactions, accompanied by significantly exothermal effects. Highly reactive nanosized ZnTiO3powders were successfully obtained at 850 °C with particle size ~50 nm. By comparison, the aqueous sol-gel process was the most effective and least expensive technique used for the preparation of ZnTiO3nanopowders.

scholarly journals Polystyrene/Montmorillonite Nanocomposites: Study of the Morphology and Effects of Sonication Time on Thermal Stability

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Mashael Alshabanat ◽  
Amal Al-Arrash ◽  
Waffa Mekhamer
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Solution Method ◽  
Sonication Time ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Polystyrene Matrix ◽  
Before And After ◽  
Silicate Layers ◽  
Thermal Stability Of

Polymer nanocomposites of polystyrene matrix containing 10% wt of organo-montmorillonite (organo-MMT) were prepared using the solution method with sonication times of 0.5, 1, 1.5, and 2 hours. Cetyltrimethylammonium bromide (CTAB) is used to modify the montmorillonite clay after saturating its surface with Na+ions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the montmorillonite before and after modification by CTAB. The prepared nanocomposites were characterized using the same analysis methods. These results confirm the intercalation of PS in the interlamellar spaces of organo-MMT with a very small quantity of exfoliation of the silicate layers within the PS matrix of all samples at all studied times of sonication. The thermal stability of the nanocomposites was measured using thermogravimetric analysis (TGA). The results show clear improvement, and the effects of sonication time are noted.

Thiol-Capped CdSe and CdTe Nanoclusters: Synthesis by a Wet Chemical Route, Structural and Optical Properties

1998 ◽  
Vol 536 ◽  
Author(s):  
A. L. Rogach ◽  
A Eychmüller ◽  
J. Rockenberger ◽  
A. Kornowski ◽  
H. Weller ◽  
...  
Keyword(s):  
Particle Size ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Chemical Route ◽  
X Ray ◽  
Stabilizing Agents ◽  
Transmission Electron ◽  
Wet Chemical ◽  
Wet Chemical Route ◽  
X Ray Absorption

AbstractCdSe and CdTe nanoclusters were formed in aqueous solutions at moderate temperatures by a wet chemical route in the presence of thiols as effective stabilizing agents. The nature of the stabilizing agent (thioalcohols or thioacids) had an important influence on the particle size and largely determined the photoluminescence properties. The nanoclusters were characterized by means of UV-vis absorption and photoluminescence spectroscopy, powder X-ray diffraction, high resolution transmission electron microscopy, and extended X-ray absorption fine structure measurements. CdSe and CdTe nanoclusters were crystalline, in the cubic zincblende phase, with mean sizes in the range of 2 to 5 nm depending on the preparative conditions and the postpreparative size-selective fractionation, and showed pronounced electronic transitions in the absorption spectra. Thioglycerol-stabilized CdTe nanoclusters possessed sharp band-egde photoluminescence being tunable with particle size.

Synthesis and Characterization of Sr3MgSi2O8:Eu2+, Dy3+ Phosphor Prepared by a Chemical Solution Method

2011 ◽  
Vol 675-677 ◽  
pp. 1089-1092 ◽  
Author(s):  
Wen Pan ◽  
Ning Hui Wang ◽  
Guo Feng Li ◽  
Gui Ling Ning
Keyword(s):  
Solution Method ◽  
Intermediate Phase ◽  
Precursor Solution ◽  
X Ray Diffraction ◽  
Calcination Process ◽  
Chemical Solution Method ◽  
Transmission Electron ◽  
Dispersion Media ◽  
Better Than

A novel synthesis route for the production of Sr3MgSi2O8:Eu2+,Dy3+ sub-micron quasisphere phosphor powder is reported. Both the host and activator cations were co-precipitated in water-ethanol mixed solutions and precipitation was performed with analytical grade ammonium citratetribasic. As the dispersion media, optimum concentration for PEG in the precursor solution is determined to be 0.08 g/mL. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and fluorescence spectrophotometer were employed to characterize the phosphor. The effect of the calcining temperature on the crystalline particle and luminescence properties of Sr3MgSi2O8:Eu2+,Dy3+ is systematically discussed. Sr3MgSi2O8:Eu2+,Dy3+ single phased quasi-sphere phosphor was achieved by calcining the asprecipitated precursor at 1100°C. Sr2SiO4 was identified as the intermediate phase during the calcination process. Despite the small particle size, the emission intensities were higher by the present method. However, the afterglow characteristic was not better than that prepared by solidstate reaction in the comparable condition.

Chemical Synthesis of Magnetic Fe3O4 Nanoparticles

2005 ◽  
Vol 475-479 ◽  
pp. 2275-2278 ◽  
Author(s):  
Rui Feng Yang ◽  
Yu Zhen Lv ◽  
Yahui Zhang ◽  
Chen Min Liu ◽  
Lin Guo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fe3o4 Nanoparticles ◽  
Solution Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Solution Method ◽  
Transmission Electron ◽  
Wet Chemical ◽  
Surface Modified

Fe3O4 nanoparticles were simply prepared by a wet chemical solution method. In this method, poly (N-vinyl-2-pyrrolidone) (PVP) was used as surface modified reagent to control the shape of the product. Transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD) were used to characterize the asprepared Fe3O4 nanoparticles. Furthermore, the magnetic properties of the sample were investigated by a VSM (vibrating sample magnetometer) technique.

Effect of Buffer or Barrier Layer on Bistability for Nonvolatile Memory Fabricated with Al Nanocrystals Embedded in α-NPD

2006 ◽  
Vol 965 ◽  
Author(s):  
Sung-ho Seo ◽  
Woo-sik Nam ◽  
Jae-seok Kim ◽  
Chang-hyup Shin ◽  
Se-yun Lim ◽  
...  
Keyword(s):  
Barrier Layer ◽  
Nonvolatile Memory ◽  
Device Structure ◽  
Transmission Electron ◽  
Non Volatile Memory ◽  
Memory Characteristic ◽  
Layer Behavior ◽  
Volatile Memory ◽  
20 Nm ◽  
Memory Characteristics

ABSTRACTRecently, low molecular organic non-volatile memories have been developed as a next generation of non-volatile memory because of nano-meter device-feature size and nano-second access and store-time. We developed a non-volatile memory fabricated with the device structure of Al/ α-NPD/Al nano-crystals surrounded by Al2O3/α-NPD/Al, where α-NPD is N,N'-bis(1-naphthyl)-1,1'biphenyl4-4”diamine. One layer of Al nano-crystals with ∼20 nm-width ∼20 nm length was uniform produced between α-NPD layers, confirmed by 1.2MV high voltage transmission-electron-microscope. This device showed Vth of 3.0 V, Vprogram of 4.3 V, and Verase of 6.3 V. Particularly, this device exhibited an excellent non-volatile memory behavior performing the bi-stability (Iprogrm/Ierase) of >1×102, program/erase cycles of >1×105 and multi-levels. In addition, previous reports about low molecular organic non-volatile memories have showed a bad reproducible memory characteristic. However, this issue was completely solved via isolating Al nano-crystals embedded in α-NPD by O2 plasma oxidation. The uniformity of Vth, Vp, and Ve were 9.91%, 6.94% and 7.92%, respectively. Furthermore, the effect of buffer or barrier layer on non-volatile memory characteristics was investigate to examine the control ability for Vth, Vp, and Ve. The 0.5-nm LiF showed a barrier layer behavior suppressing the bi-stability of non-volatile memory. Otherwise, 15-nm CuPc exhibited a buffer layer behavior enhancing the bi-stability of nonvolatile memory.

SYNTHESIS AND CHARACTERIZATION OF BIFUNCTIONAL CoFe2O4–ZnS NANOCOMPOSITE

2011 ◽  
Vol 10 (01n02) ◽  
pp. 237-240 ◽  
Author(s):  
J. P. BORAH ◽  
C. BORGOHAIN ◽  
K. C. SARMA ◽  
K. K. SENAPATI ◽  
P. PHUKAN
Keyword(s):  
Drug Targeting ◽  
Room Temperature ◽  
Cobalt Ferrite ◽  
Magnetic Nanomaterials ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Magnetic Fluid Hyperthermia ◽  
X Ray ◽  
Transmission Electron

The synthesis of composite magnetic nanomaterials has received increasing attention due to their electronic, magnetic, catalytic, and chemical or biological sensing properties. We have prepared cobalt ferrite–zinc sulfide nanocomposites by a chemical route. The synthesized nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and photoluminescence spectrometer (PL). The fluorescent magnetic nanoparticles (FMNPs) had a typical diameter of 30±5 nm and saturation magnetization of 5.8 emu g-1 at room temperature. So, these FMNPs may be potentially applied in different fields such as optoelectronic devices, biolabeling, imaging, drug targeting, bioseparation, magnetic fluid hyperthermia, etc.

Preparation, Characterization and Application in Electromagnetic Wave Absorption of Core-Shell C/Fe3O4 Nanocomposites

2011 ◽  
Vol 239-242 ◽  
pp. 1725-1730 ◽  
Author(s):  
Qiang Chun Liu ◽  
Jian Ming Dai ◽  
Zhen Fa Zi ◽  
Da Jun Wu ◽  
Yu Ping Sun
Keyword(s):  
Electron Microscopy ◽  
Solution Method ◽  
Wide Frequency Range ◽  
Core Shell ◽  
Carbon Sphere ◽  
Carbon Spheres ◽  
X Ray Diffraction ◽  
Microwave Absorption Properties ◽  
Transmission Electron ◽  
Better Than

Large-quantity core-shell carbon spheres/Fe3O4nanocomposites were synthesized via a simple solution method. The phase structures and morphologies of the composite had been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the carbon spheres were covered by a layer of Fe3O4nanoparticles with a diameter of about 25 nm. Measurements of the electromagnetic parameters of the samples showed that microwave absorption properties of the carbon sphere-Fe3O4nanocomposites were much better than that of the pure Fe3O4or the mixtures of carbon spheres and Fe3O4microspheres. The optimal reflection loss (RL) reached −37.8 dB at 14.8 GHz for a layer thickness of 2.0 mm, which is favorable for application of our samples in a wide frequency range.

Synthesis and Characterization of Rare Earth (Tb3+ and Yb3+) Doped CdS/ZnS Core/Shell Nanocrystals for Enhanced Photovoltaic Efficiency

2011 ◽  
Vol 1322 ◽  
Author(s):  
Sandip Das ◽  
Krishna C. Mandal
Keyword(s):  
Rare Earth ◽  
Uv Light ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
X Ray ◽  
Broadband Absorption ◽  
Photovoltaic Efficiency ◽  
Transmission Electron

ABSTRACTCdS host nanocrystals with 4.2-5.5 nm in diameter have been synthesized from air stable precursors via a synthetic chemical route and doped with rare earth (RE) terbium (Tb3+) and ytterbium (Yb3+) ions. RE3+-doped CdS cores were shelled by ZnS layers of different thicknesses. The resulting core/shell nanocrystals show a complete broadband absorption below 400-460 nm to the deep UV region depending on the size of the cores. RE3+-doped CdS nanocrystals showed a red shift in the emission as observed under irradiation of 302 nm UV light and was confirmed by room temperature photoluminescence (PL) measurements. The nanocrystals were further characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), and energy dispersive x-ray (EDX) analysis. The results show that these RE3+-doped nanocrystals can be used as solar spectral matching downconversion material to enhance photovoltaic efficiency of existing solar cells.

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