Scallion-Root-Shaped GaN Nanorods Grown by Two-Step Method and Study on their Properties

2013 ◽  
Vol 652-654 ◽  
pp. 197-201
Author(s):  
Yu Ping Cao ◽  
Hai Bo Sun
Keyword(s):  
High Purity ◽  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Hexagonal Wurtzite Structure ◽  
X Ray Diffraction ◽  
Step Method ◽  
X Ray ◽  
Band Emission ◽  
Growth Method ◽  
Step Growth

Two-step growth technology to successfully synthesize scallion-root-shaped GaN nanorods was presented in this paper. This growth method is applicable to continuous synthesis a large number of single-crystalline GaN nanorods with a high purity at a low cost. X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) are employed to characterize the structure, composition and morphology of as-grown GaN nanorods. The results show that the obtained nanorods are single-crystal GaN with hexagonal wurtzite structure and have a relatively high purity. The diameter of the nanorods is about 500nm with length up to several tens of micrometers. The representative photoluminescence spectra (PL) measured at room temperature exhibited a strong and broad emission peak at 388nm corresponding to the strong-band-emission in wurtzite GaN, indicating that the nanorods have a good emission property. The growth mechanism is also briefly discussed.

A Comparative Study of GaN Films Grown on Different Faces of Sapphire by ECR-Assisted MBE

1992 ◽  
Vol 242 ◽  
Author(s):  
T. D. Moustakas ◽  
R. J. Molnar ◽  
T. Lei ◽  
G. Menon ◽  
C. R. Eddy
Keyword(s):  
Surface Morphology ◽  
Low Temperatures ◽  
Smooth Surface ◽  
Growth Process ◽  
X Ray Diffraction ◽  
Epitaxial Relationship ◽  
X Ray ◽  
Sapphire Substrates ◽  
Growth Method ◽  
Step Growth

ABSTRACTGaN films were grown on c-plane (0001), a-plane (1120) and r-plane (1102) sapphire substrates by the ECR-assisted MBE method. The films were grown using a two-step growth process, in which a GaN buffer is grown first at relatively low temperatures and the rest of the film is grown at higher temperatures. RHEED studies indicate that this growth method promotes lateral growth and leads to films with smooth surface morphology. The epitaxial relationship to the substrate, the crystalline quality and the surface morphology were investigated by RHEED, X-ray diffraction and SEM studies.

scholarly journals Nanosheets of CuCo2O4 As a High-Performance Electrocatalyst in Urea Oxidation

2019 ◽  
Vol 9 (4) ◽  
pp. 793 ◽  
Author(s):  
Camila Zequine ◽  
Fangzhou Wang ◽  
Xianglin Li ◽  
Deepa Guragain ◽  
S.R. Mishra ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Nickel Foam ◽  
Low Cost ◽  
Agricultural Waste ◽  
Bifunctional Catalyst ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electroactive Material

The urea oxidation reaction (UOR) is a possible solution to solve the world’s energy crisis. Fuel cells have been used in the UOR to generate hydrogen with a lower potential compared to water splitting, decreasing the costs of energy production. Urea is abundantly present in agricultural waste and in industrial and human wastewater. Besides generating hydrogen, this reaction provides a pathway to eliminate urea, which is a hazard in the environment and to people’s health. In this study, nanosheets of CuCo2O4 grown on nickel foam were synthesized as an electrocatalyst for urea oxidation to generate hydrogen as a green fuel. The synthesized electrocatalyst was characterized using X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The electroactivity of CuCo2O4 towards the oxidation of urea in alkaline solution was evaluated using electrochemical measurements. Nanosheets of CuCo2O4 grown on nickel foam required the potential of 1.36 V in 1 M KOH with 0.33 M urea to deliver a current density of 10 mA/cm2. The CuCo2O4 electrode was electrochemically stable for over 15 h of continuous measurements. The high catalytic activities for the hydrogen evolution reaction make the CuCo2O4 electrode a bifunctional catalyst and a promising electroactive material for hydrogen production. The two-electrode electrolyzer demanded a potential of 1.45 V, which was 260 mV less than that for the urea-free counterpart. Our study suggests that the CuCo2O4 electrode can be a promising material as an efficient UOR catalyst for fuel cells to generate hydrogen at a low cost.

An Efficient Simple Hydrothermal Method to Synthesis FeS2 Microspheres and their Optical Property

2016 ◽  
Vol 847 ◽  
pp. 72-77
Author(s):  
Yu Xuan Liang ◽  
Peng Peng Bai ◽  
Shu Qi Zheng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Wave Length ◽  
Functional Materials ◽  
Optical And Electrical Properties ◽  
X Ray Diffraction ◽  
Synthetic Sample ◽  
X Ray ◽  
New Type ◽  
Good Uniformity

Pyrite (FeS2) is an important semiconductor material which shows various excellent optical and electrical properties and extensive applied prospect as a new-type, photoelectrical functional materials. In this study, a low cost and efficient simple hydrothermal two-step synthetic method was given to obtain FeS2 microspheres with 2-3 μm in diameter. The obtained products were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet and visible spectrophotometer (UV-Vis). XRD showed that the synthetic sample consisted of two crystal structures of FeS2, pyrite and marcasite. SEM observation indicated that FeS2 microspheres were well crystallized and had good uniformity. UV-Vis spectrum had a strong optical absorption in the region of 200-400 nm wave length. The reaction temperature had an impact on the size of FeS2 microspheres. A possible mechanism for the size of the FeS2 microspheres generated at high temperature is smaller than that at low temperature is discussed.

FORMATION OF GaN FILM BY AMMONIATING Ga2O3 DEPOSITED ON Si SUBSTRATE WITH ELECTROPHORESIS

2002 ◽  
Vol 16 (28n29) ◽  
pp. 4267-4270 ◽  
Author(s):  
LI YANG ◽  
CHENGSHAN XUE ◽  
HUIZHAO ZHUANG ◽  
HUAIXIANG LI ◽  
QINQIN WEI
Keyword(s):  
Fourier Transform ◽  
Gallium Nitride ◽  
Photoelectron Spectroscopy ◽  
Fourier Transform Infrared ◽  
Hexagonal Wurtzite Structure ◽  
Wurtzite Structure ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
X Ray ◽  
Gan Film

The gallium nitride (GaN) films have been successfully fabricated on silicon (111) substrates through ammoniating Ga 2 O 3 films deposited by electrophoresis. The structure and composition of the formed films were characterized by Fourier transform infrared (FTIR) transmission spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results indicate that the films formed in this study are polycrystalline GaN with hexagonal wurtzite structure.

Low Cost Integrated Sensors Utilizing Patterned Nano-Structured Titania Arrays Fabricated Using a Simple Process

2004 ◽  
Vol 828 ◽  
Author(s):  
Zuruzi Abu Samah ◽  
Andrei Kolmakov ◽  
Martin Moskovits ◽  
Noel C. MacDonald
Keyword(s):  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Aqueous Hydrogen Peroxide ◽  
X Ray ◽  
Sensing Systems ◽  
Potential Applications ◽  
Nano Wires ◽  
Low Temperature Process

ABSTRACTUsing a novel low-temperature process, we demonstrate the facile integration of crack-free nanostructured titania (NST) as sensing elements in microsystems. Unlike conventional sol-gel methods, NST layers of interconnected nano-walls and nano-wires were formed by reacting Ti surfaces with aqueous hydrogen peroxide solution. Cracks were observed in NST layers formed on blanket Ti films but absent on arrays of patterned Ti pads below a threshold dimension. Analyses using TEM, high resolution SEM, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) reveal that NST consists of anatase TiO2 nano-crystals. NST pads were found able to detect oxygen gas of a few ppm. NST pad arrays were integrated on rigid and flexible substrates with potential applications in low cost and wearable sensing systems.

scholarly journals Sorption of Molybdates and Tungstates on Functionalized Montmorillonites: Structural and Textural Features

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2253 ◽  
Author(s):  
Magdalena Tuchowska ◽  
Barbara Muir ◽  
Mariola Kowalik ◽  
Robert P. Socha ◽  
Tomasz Bajda
Keyword(s):  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Inorganic Compounds ◽  
Ammonium Bromide ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Mineral Sorbent ◽  
Dimethyl Ammonium

Montmorillonite—the most popular mineral of the smectite group—has been recognized as a low-cost, easily available mineral sorbent of heavy metals and other organic and inorganic compounds that pollute water. The aim of this work was to determine the sorption mechanism and to identify the reaction products formed on the surface of montmorillonite and organo-montmorillonite after sorption of molybdates (Mo(VI)) and tungstates (W(VI)). Montmorillonites are often modified to generate a negative charge on the surface. The main objective of the study was to investigate and compare the features of Na-montmorillonite (Na-M), montmorillonite modified with dodecyl trimethyl ammonium bromide (DDTMA-M), and montmorillonite modified with didodecyl dimethyl ammonium bromide (DDDDMA-M) before and after sorption experiments. The material obtained after sorption was studied by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The XRD pattern showed the presence of a new crystallic phase in the sample that was observed under an SEM as an accumulation of crystals. The FTIR spectra showed bands related to Mo–O and W–O vibration (840 and 940 cm−1, respectively). The obtained results suggest that molybdenum(VI) and tungsten(VI) ions sorb onto the organo-montmorillonite in the form of alkylammonium molybdates and tungstates.

CO2 Adsorption Performance of N-Doped Ordered Microporous Carbons Templated from Zeolite HY

2011 ◽  
Vol 284-286 ◽  
pp. 2102-2105 ◽  
Author(s):  
Jin Zhou ◽  
Wen Li ◽  
Shu Ping Zhuo
Keyword(s):  
Photoelectron Spectroscopy ◽  
Carbon Deposition ◽  
X Ray Diffraction ◽  
Step Method ◽  
X Ray ◽  
Microporous Carbons ◽  
Adsorption Performance ◽  
Basic Nitrogen ◽  
Diffraction Patterns ◽  
Very High

Several microporous carbons were prepared by a two-step method using zeolite HY as a template, and were used as CO2 adsorbents. X-ray diffraction patterns present that the structure regularity of the zeolite has been well-replicated by the templated carbons. X-ray photoelectron spectroscopy confirms that the prepared carbons possess abundant nitrogen-containing groups due to the carbon deposition of acetonitrile. The prepared carbons show high CO2 adsorption capacity due to its very high microporous surface area and abundant basic nitrogen-containing groups.

Simplified Synthesis and Luminous Mechanism of Eu2+-Doped α-Si3N4 Nanowires with Strong Green Luminescent Properties

2017 ◽  
Vol 727 ◽  
pp. 635-641 ◽  
Author(s):  
Rui Su ◽  
Zhi Feng Huang ◽  
Fei Chen ◽  
Qiang Shen ◽  
Lian Meng Zhang
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Broad Band ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Broad Band Emission ◽  
Band Emission ◽  
Nitridation Process ◽  
Transmission Electron

Ultra-long, single crystal, Eu-doped α-Si3N4 nanowires were prepared by a simple approach involving nitriding Eu-doped cryomilled nanocrystalline Si powder in NH3 flow at 1350 °C for 4 h. Phases, chemical composition and microcosmic feature of cryomilled powders and as-prepared nanowires were tested by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), respectively. The results suggested that Eu was successfully introduced into Si lattice after the cryomilling process and then entered into the lattice of α-Si3N4 during the nitridation process. The as-synthesized Eu-doped α-Si3N4 nanowires had highly uniform dimension with 20~30 nm in diameter and ~100 μm in length. The room temperature photoluminescence (PL) spectrum of as-synthesized nanowires showed a broad band emission center at 570 nm which was attributed to the transition from 4f65d to 4f7 in Eu2+. The transition from Eu3+ to Eu2+ during nitridation process was tested by X-ray photoelectron spectroscopy (XPS).

Hydrothermal Synthesis of Flower-Like ZnO Nanostructures and their Optical Properties

2013 ◽  
Vol 678 ◽  
pp. 91-96
Author(s):  
Krishnan Sambath ◽  
Manickam Saroja ◽  
Muthusamy Venkatachalam ◽  
Krishnan Rajendran ◽  
Kumaravelu Jagatheeswaran
Keyword(s):  
Visible Region ◽  
Blue Emission ◽  
Hexagonal Wurtzite Structure ◽  
Zinc Nitrate ◽  
Near Band Edge ◽  
Nitrate Hexahydrate ◽  
Zno Nanostructures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Band Emission

Flower-like ZnO nanostructures have been synthesized using zinc nitrate hexahydrate and hexamethylenetetramine (HMT) by a low-temperature hydrothermal technique. The prepared ZnO nanostructures exhibit hexagonal wurtzite structure, well-defined flower-like morphology, and a strong blue emission photoluminescence. Flower-like ZnO nanostructures consisting of multilayered petals are formed with the length of about 1 μm. All the flower petals exhibit the tapering feature with the root size of 300-500 nm and tip size of 50-100 nm. The prepared ZnO sample has been studied using x-ray diffraction technique, energy dispersive x-ray analysis, scanning electron microscope and FTIR spectroscopy. The photoluminescence spectrum demonstrated two emission bands, a near band edge (NBE) emission in the UV region centering at 386 nm and a high intensity deep band emission (DBE) in the visible region centering at 483 nm.

Preparation, Characterization of Phosphorus Doped Titania Photocatalysts with High Photocatalystic Properties

2010 ◽  
Vol 113-116 ◽  
pp. 2154-2157 ◽  
Author(s):  
Si Yao Guo ◽  
Jin Bing Sun ◽  
Feng Lu Wang ◽  
Lin Yang ◽  
Feng Zhang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Titania Nanoparticles ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Step Method ◽  
X Ray ◽  
One Step ◽  
Titania Photocatalyst ◽  
Calcination Method ◽  
Doped Titania

Phosphor-doped titania nanoparticles were synthesized by a one step method, which were prepared by conventional calcination method. These samples have much higher photocatalytic activity for methylene blue degradation. The resulting materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), etc. Moreover, we use high P/TiO2 molar ratio to get the most suitable proportion for the synthesis of P-doped titania photocatalyst.

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