Study of Growth and Characterization of Fe-Catalyzed β-Ga2O3 Nanowires

2015 ◽  
Vol 1751 ◽  
Author(s):  
Sudheer Kumar ◽  
C. Tessarek ◽  
A. Hähnel ◽  
S. Christiansen ◽  
R. Singh
Keyword(s):  
Emission Band ◽  
Blue Emission ◽  
Chemical Vapor ◽  
Luminescence Properties ◽  
Chemical Vapor Deposition Method ◽  
X Ray Diffraction ◽  
Blue Emission Band ◽  
Single Crystalline ◽  
Transmission Electron ◽  
High Resolution Tem

ABSTRACTIn the present study, Fe as a catalyst was used to grow single crystalline monoclinic gallium oxide (β-Ga2O3) nanowires using chemical-vapor-deposition method. The morphology, structure and luminescence properties of the as-grown β-Ga2O3 nanowires were investigated using various characterization techniques. The diameter of the as-grown nanowires was in the range of 50 to 100 nm, and the lengths up to tens of micrometers. The structural investigation of the nanowires was carried out using X-ray diffraction that showed monoclinic phase of Ga2O3. Further, the transmission electron microscope (TEM) investigations along with selected area diffraction pattern revealing single crystalline nature of the nanowires. The as-grown β-Ga2O3 nanowires had preferred orientation along [1-1-1] direction. The high resolution TEM image showed regular arrangement of atoms and the lattice spacing between (1-1-1) planes was around 0.266 nm. The luminescence properties of the as-grown nanowires were measured using cathodoluminescence (CL) spectroscopy. The CL measurements of β-Ga2O3 nanowires revealed a strong broad UV-blue emission band and a weak red emission band.

SYNTHESIS OF CaWO4 AND CaWO4:Eu MICROSPHERES BY PRECIPITATION

NANO ◽  
2014 ◽  
Vol 09 (01) ◽  
pp. 1450008 ◽  
Author(s):  
YUGUO YANG ◽  
XUPING WANG ◽  
BING LIU
Keyword(s):  
Electron Microscopy ◽  
Emission Band ◽  
Large Scale ◽  
Blue Emission ◽  
Average Diameter ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
Blue Emission Band ◽  
Transmission Electron ◽  
Cetyltrimethyl Ammonium

Nearly monodisperse CaWO 4 and CaWO 4: Eu 3+ microspheres have been synthesized in large scale by a surfactant-assisted solution route, in which cetyltrimethyl ammonium bromide (CTAB) is used. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and photoluminescence (PL) were used to characterize the resulting samples. The results of XRD indicate that the CaWO 4 and CaWO 4: Eu 3+ samples have the scheelite structures. The growth process of these nearly monodisperse spheres with an average diameter around 3.2 μm has been examined. The results of FTIR indicate that CTAB plays an important role in the formation of microspheres. The CaWO 4 microspheres exhibit a blue emission band with a maximum at 423 nm. But the CaWO 4: Eu 3+ microspheres exhibit a red emission band with a maximum at 623 nm.

scholarly journals Fabrication and Physical Properties of Single-Crystalline Βeta-FeSi2 Nanowires

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Chih-Yung Yang ◽  
Shu-Meng Yang ◽  
Yu-Yang Chen ◽  
Kuo-Chang Lu
Keyword(s):  
Electron Microscopy ◽  
Physical Properties ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Field Emitters ◽  
Transmission Electron ◽  
Single Source Precursor ◽  
Carrier Gases

Abstract In this study, self-catalyzed β-FeSi2 nanowires, having been wanted but seldom achieved in a furnace, were synthesized via chemical vapor deposition method where the fabrication of β-FeSi2 nanowires occurred on Si (100) substrates through the decomposition of the single-source precursor of anhydrous FeCl3 powders at 750–950 °C. We carefully varied temperatures, duration time, and the flow rates of carrier gases to control and investigate the growth of the nanowires. The morphology of the β-FeSi2 nanowires was observed with scanning electron microscopy (SEM), while the structure of them was analyzed with X-ray diffraction (XRD) and transmission electron microscopy (TEM). The growth mechanism has been proposed and the physical properties of the iron disilicide nanowires were measured as well. In terms of the magnetization of β-FeSi2, nanowires were found to be different from bulk and thin film; additionally, longer β-FeSi2 nanowires possessed better magnetic properties, showing the room-temperature ferromagnetic behavior. Field emission measurements demonstrate that β-FeSi2 nanowires can be applied in field emitters.

Control of Morphology and Growth Direction of Gallium Nitride Nanostructures

2003 ◽  
Vol 789 ◽  
Author(s):  
Seung Yong Bae ◽  
Hee Won Seo ◽  
Jeunghee Park
Keyword(s):  
Electron Microscopy ◽  
Gallium Nitride ◽  
Large Scale ◽  
Chemical Vapor ◽  
Growth Direction ◽  
Chemical Vapor Deposition Method ◽  
X Ray Diffraction ◽  
Oxide Mixture ◽  
Temperature Range ◽  
Transmission Electron

ABSTRACTVarious shaped single-crystalline gallium nitride (GaN) nanostructures were produced by chemical vapor deposition method in the temperature range of 900–1200 °C. Scanning electron microscopy, transmission electron microscopy, electron diffraction, x-ray diffraction, electron energy loss spectroscopy, Raman spectroscopy, and photoluminescence were used to investigate the structural and optical properties of the GaN nanostructures. We controlled the GaN nanostructures by the catalyst and temperature. The cylindrical and triangular shaped nanowires were synthesized using iron and gold nanoparticles as catalysts, respectively, in the temperature range of 900 – 1000 °C. We synthesized the nanobelts, nanosaws, and porous nanowires using gallium source/ boron oxide mixture. When the temperature of source was 1100 °C, the nanobelts having a triangle tip were grown. At the temperature higher up to 1200 °C the nanosaws and porous nanowires were formed with a large scale. The cylindrical nanowires have random growth direction, while the triangular nanowires have uniform growth direction [010]. The growth direction of the nanobelts is perpendicular to the [010]. Interestingly, the nanosaws and porous nanowires exhibit the same growth direction [011]. The shift of Raman, XRD, and PL bands from those of bulk was correlated with the strains of the GaN nanostructures.

A new langbeinite-type phosphate K2GdHf(PO4)3: synthesis, crystal structure, band structure and luminescence properties

2020 ◽  
Vol 76 (8) ◽  
pp. 771-778
Author(s):  
Hua Nan ◽  
Li Chen ◽  
Rui-Juan Zhang ◽  
Dan Zhao
Keyword(s):  
Optical Transition ◽  
Blue Emission ◽  
Large Family ◽  
Luminescence Properties ◽  
X Ray Diffraction ◽  
Blue Emission Band ◽  
Light Emitting ◽  
Direct Band ◽  
Cie Chromaticity ◽  
White Light Emitting Diodes

Langbeinite-type compounds are a large family that include phosphates, sulfates and arsenates, and which are accompanied by interesting physical properties. This work reports a new disordered langbeinite-type compound, K2GdHf(PO4)3 [dipotassium gadolinium hafnium tris(phosphate)], and its structure as determined by single-crystal X-ray diffraction. Theoretical studies reveal that K2GdHf(PO4)3 is an insulator with a direct band gap of 4.600 eV and that the optical transition originates from the O-2p→Hf-5d transition. A Ce3+-doped phosphor, K2Gd0.99Ce0.01Hf(PO4)3, was prepared and its luminescence properties studied. With 324 nm light excitation, a blue emission band was observed due to the 5d 1→4f 1 transition of Ce3+. The average luminescence lifetime was calculated to be 5.437 µs and the CIE chromaticity coordinates were (0.162, 0.035). One may expect that K2Gd0.99Ce0.01Hf(PO4)3 can be used as a good blue phosphor for three-colour white-light-emitting diodes (WLEDs).

Effect of Microwave Irradiation Synthesis of ZnO Nanoparticles

2016 ◽  
Vol 19 (1) ◽  
pp. 021-026 ◽  
Author(s):  
Chelladurai Amutha ◽  
Balan Natarajan ◽  
Sethuramachandran Thanikaikarasan ◽  
Adaikalam Cyrac Peter ◽  
Thaiyan Mahalingam ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Emission Band ◽  
Blue Emission ◽  
Hexagonal Structure ◽  
X Rays ◽  
X Ray Diffraction ◽  
Ultraviolet Emission ◽  
Blue Emission Band ◽  
Diffraction Patterns ◽  
Bending Modes

Zinc Oxide nanoparticles were synthesized from zinc acetate by microwave irradiation method. X-ray diffraction patterns showed that the prepared samples found to exhibit hexagonal structure. Surface morphology and presence of elements have been analyzed using scanning electron microscopy and energy dispersive analysis by X-rays. The presence of stretching and bending modes in the prepared samples has been determined using Fourier transform infrared spectroscopy. Optical absorption analysis showed that the prepared samples possess band gap value around 3.02 eV. Photoluminescence spectroscopic analysis indicated a strong ultraviolet emission band at 390 nm and a weak blue - green band and weak blue emission band at 484 and 444 nm respectively.

Effect of oxygen vacancies on the surface morphology and structural properties of WO3– x nanoparticles

2019 ◽  
Vol 9 (7) ◽  
pp. 773-777 ◽  
Author(s):  
Zhiguang Yang ◽  
Chaosheng Zhu ◽  
Zhiqiang Hou ◽  
Peng Peng
Keyword(s):  
Electron Microscopy ◽  
Active Sites ◽  
Oxygen Vacancies ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Diffraction Field ◽  
Chemical Vapor Deposition Method ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Effect Of Oxygen

WO3 is an essential material for energy storage and catalytical technology, the oxygen vacancies level will play an essential role in its potential application. In this paper, porous tungsten oxide (WO3–x) with various oxygen contents was quickly fabricated by a microwave plasma-enhanced chemical vapor deposition method. A detailed characterization of structure and morphology features with the plasma handling process was recorded by X-ray diffraction, field-emission scanning electron microscopy and transmission electron microscopy, respectively. The etching mechanism of porous WO3–x under H2 plasma was discussed based on the systemically characterization. These results will help us to design the active sites or structure in the metal oxide materials.

A Simple Method to Synthesize Nano-Sized 3C-SiC Powder Using Hexamethyldisilane in a CVD Reactor

2006 ◽  
Vol 527-529 ◽  
pp. 767-770 ◽  
Author(s):  
Aparna Gupta ◽  
Chacko Jacob
Keyword(s):  
Growth Parameters ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Cold Region ◽  
Simple Method ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Cubic Silicon Carbide ◽  
Shaped Pattern

In this paper, we report a novel route to synthesize nano-sized cubic silicon carbide (3CSiC) powder by a chemical vapor deposition (CVD) technique in a resistance-heated furnace. The nanoparticles were deposited on the relatively cold region of a hot-wall quartz reactor. Hexamethyldisilane (HMDS) was used as the source material for both silicon and carbon. The presence of crystalline 3C-SiC was identified using powder x-ray diffraction (XRD) technique. From the XRD data, the crystallite size was also estimated to be in the range of nanometers (nm). A clear evidence of the particle size (~ 10 - 30 nm) was obtained by transmission electron microscopy (TEM). Selected area electron diffraction (SAED) was carried out on the nanoparticle assembly. The ring shaped pattern is a clear indication of polycrystalline particle formation. High resolution TEM (HRTEM) of nanoparticles was performed to study the crystal structure in detail. The nanoparticles were also characterized by Raman spectroscopy at room temperature. Finally, the influence of the growth parameters is also reported in the present study.

Growth and Photoluminescence of β-SiC Nanowires on Porous Silicon Array

2013 ◽  
Vol 662 ◽  
pp. 11-15
Author(s):  
Hai Yan Wang ◽  
Li Ping Kang ◽  
Yong Qiang Wang ◽  
Zi Jiong Li
Keyword(s):  
Electron Microscopy ◽  
Porous Silicon ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Fluorescent Light ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sic Nanowires ◽  
Quantum Confinement Effects ◽  
Transmission Electron

Nonaligned and curly β-SiC nanowires (nw-SiC) were grown on porous silicon array (PSA) by a chemical vapor deposition method with nickel as the catalyst. The morphology, structure and the composition of the nw-SiC/PSA and the SiC-SiO2core-shell fibers which is the semi-product were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Based on the experimental results a possible growth mechanism of nw-SiC was explained. Two broad photoluminescence peaks located around ~409 and ~494 nm were observed in nw-SiC/PSA in the PL measurement when utilizing 300 nm ultraviolet fluorescent light excited at room temperature. The excellent luminescent performances are ascribed to the quantum confinement effects in nw-SiC. The optical merits of nw-SiC/PSA made it a promising material in the fields of ultraviolet-blue emitting devices.

scholarly journals Synthesis and Optical Properties of CdSxSe1-x Semiconductor Nanomaterials by Chemical Vapor Deposition Method

2019 ◽  
Vol 12 (3) ◽  
pp. 55-64
Author(s):  
Nadia M. Jassim
Keyword(s):  
Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Growth Direction ◽  
Chemical Vapor Deposition Method ◽  
X Ray Diffraction ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Vls Growth

Highly pure and crystalline CdSxSe1 -x nanostructures have been successfully synthesized via Chemical Vapor Deposition (CVD) method, changing the components of x, in order to adjust the band gap of materials, and the relationship with the lattice constant. Using X-ray Diffraction (XRD) to characterize the phase structures and elemental compositions of the samples, and using Field Emission Scanning Electron Microscopy (FESEM) to observe the surface morphology of CdSxSe1 -x nanomaterials and confirm the VLS growth mechanism. Using the High Resolution Transmission Electron Microscopy (HRTEM) and Selected Area Electron Diffraction (SAED) to analyze the crystal structure and the growth direction of the materials

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