scholarly journals Elongated Wire-Like Zinc Oxide Nanostructures Synthesized from Metallic Zinc

2012 ◽  
Vol 15 (1) ◽  
pp. 19 ◽  
Author(s):  
El-Shazly M. Duraia ◽  
G.W. Beall ◽  
Zulkhair A. Mansurov ◽  
Tatyana A. Shabanova ◽  
Ahmed E. Hannora
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Silicon Substrate ◽  
Gas Flow ◽  
Flow Direction ◽  
Crystal Defects ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Metallic Zinc ◽  
Zinc Oxide Nanostructures

Elongated wire-like Zinc oxide, nanocombs and nanocrystals have been successfully synthesized on the silicon substrate from the metallic zinc as a starting material. The annealing temperature was as low as 450 ºC in argon atmosphere mixed with about 3% oxygen. Structural analysis using the X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) showed that the existence of two phases; nanowires and crystalline form. Moreover some nanoparticles aggregates were noticed to be attached in the bulk to the sides of the ZnO nanocrystals and sometimes these aggregate attached to the Zinc oxide hexagonal crystal and grow to form nanowire at different angles. Scanning electron microscopy (SEM) investigations for the zinc oxide nanostructure on the silicon substrate showed the formation of the nanocrystals in the gas flow direction and at the low energy sites over the silicon substrate. Photoluminescence (PL) measurements, performed at the room temperature, showed the existence of two basic emissions: narrow ultraviolet (UV) emission at 398 nm which attributed to the near band edge emission of the wide band gap and a very wide, more intensive, green emission at 471 nm corresponds to the crystal defects such as vacancies, interstitial sites in ZnO.

Wet Oxidation: A Promising Way for Fabrication of Zinc Oxide Nanostructures

2006 ◽  
Vol 522-523 ◽  
pp. 277-284 ◽  
Author(s):  
Wei Gao ◽  
Zheng Wei Li
Keyword(s):  
Zinc Oxide ◽  
Ultra Violet ◽  
Zno Films ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Zinc Oxide Nanostructures ◽  
Violet Emission ◽  
Red Color ◽  
Controllable Growth ◽  
Porous Oxide

A two-step deposition-oxidation method was successfully developed to fabricate zinc oxide thin films and nanostructures. Morphological observations clearly showed that a controllable growth of dense/porous oxide films, nanowhiskers, nanowires, and nanobelts could be obtained by controlling the deposition and oxidation conditions. Photoluminescence properties of the ZnO films were also studied. A strong and predominant ultra-violet near-band-edge emission could be observed on most of the samples, while a green or red color emission accompanying with a largely suppressed ultra-violet emission could be realized on the samples with different processing conditions. The results therefore indicated that ZnO films and structures with desirable microstructural and optical properties could be obtained with this deposition-oxidation technique under controllable conditions.

Characterization of Urea versus HMTA in the Preparation of Zinc Oxide Nanostructures by Solution-Immersion Method Grown on Gold-Seeded Silicon Substrate

2011 ◽  
Vol 364 ◽  
pp. 45-49 ◽  
Author(s):  
Azlinda Ab Azlinda ◽  
Zuraida Khusaimi ◽  
Saifollah Abdullah ◽  
Mohamad Rusop
Keyword(s):  
Zinc Oxide ◽  
Silicon Substrate ◽  
High Surface ◽  
High Surface Area ◽  
Zinc Nitrate ◽  
Nitrate Hexahydrate ◽  
Zno Nanostructures ◽  
Zinc Oxide Nanostructures ◽  
Immersion Method ◽  
Oxide Nanostructures

Zinc oxide (ZnO) nanostructures prepared by immersion method were successfully grown on gold-seeded silicon substrate using Zinc nitrate hexahydrate (Zn (NO3)2.6H2O) as a precursor, separately stabilized with non-toxic urea (CH4N2O) and hexamethylene tetraamine (HMTA). The effect of changing the stabilizer of ZnO solution on the crystal structure, morphology and photoluminescence properties of the resultant ZnO is investigated. X-ray diffraction of the synthesized ZnO shows hexagonal zincite structure. The morphology of the ZnO was characterized using Field Emission Scanning Electron Microscope (FESEM). The growth of ZnO using urea as stabilizer shows clusters of ZnO nanoflower with serrated broad petals were interestingly formed. ZnO in HMTA showed growth of nanorods. The structures has high surface area, is a potential metal oxide nanostructures to be develop for optoelectronic devices and chemical sensors. The formation of ZnO nanostructures is found to be significantly affected by the stabilizer.

Growth and Characterization of Misostructural Zinc Oxide Tubes

2005 ◽  
Vol 23 ◽  
pp. 293-296
Author(s):  
X.W. Sun ◽  
C.X. Xu ◽  
B.J. Chen ◽  
Y. Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Zinc Oxide ◽  
Growth Process ◽  
Hexagonal Structure ◽  
Metallic Zinc ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Zinc oxide (ZnO) microtube has been fabricated by heating the mixture of ZnO and graphite powders in the atmosphere. The ZnO microtubes showed perfect hexagonal profiles with bell-mouth or normal hexagonal tops. Both X-ray diffraction (XRD) and high-resolution transmission electron microscopy (TEM) demonstrated that the product was composed of ZnO with typical hexagonal structure grown predominantly along (002) direction. The growth process was interpreted by means of vaporliquid-solid mechanism combining with the evaporation of metallic zinc.

scholarly journals The effects of gas flow rate and annealing on the morphological properties of zinc oxide nanostructures thin film using chemical vapour deposition process

2017 ◽  
Vol 13 (1) ◽  
Author(s):  
W. H. Khoo ◽  
S. M. Sultan ◽  
M. Z. Sahdan
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Chemical Vapour Deposition ◽  
Gas Flow ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Zinc Oxide Nanostructures ◽  
Glass Substrates ◽  
Oxide Nanostructures ◽  
Chemical Vapour Deposition Technique

Zinc Oxide nanostructures thin films have been deposited on glass substrates by using chemical vapour deposition technique at 1000°C assisted by gas blocker. Glass substrates was sputtered by ~5nm of gold to form a catalyst layer on top of glass. Different gas flow rates of 0.05, 0.10, 0.20, 0.40 L/min were used in the deposition. After the deposition, the layer was annealed at temperatures of 500°C for 1 hours under atmospheric pressure. The surface morphologies of ZnO thin film were investigated field emission scanning electron microscope (FESEM). X-ray diffraction (XRD) results confirm the presence of ZnO layer with high peak of (002) crystal orientation and shows improvement after annealing. The mechanism of ZnO nanostructures formation will be discussed in this paper

Efficient reduction of formic acid to formaldehyde by zinc

2019 ◽  
Vol 97 (1) ◽  
pp. 42-45 ◽  
Author(s):  
Nicholas P. Alderman ◽  
Virginie Peneau ◽  
Camilo J. Viasus ◽  
Ilia Korobkov ◽  
Balamurugan Vidjayacoumar ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Formic Acid ◽  
Gas Flow ◽  
Methyl Formate ◽  
Metallic Zinc ◽  
Secondary Products ◽  
Flow Temperature ◽  
Low Concentrations ◽  
Efficient Reduction ◽  
Carrier Gas Flow

The possibility of thermally reducing formic acid to formaldehyde selectively has been probed using metallic zinc. Good selectivity (over 80%) was obtained with low concentrations of formic acid, with methanol and methyl formate as secondary products. The selectivity can be tuned by changing the carrier gas flow, temperature, and zinc amount. Zinc was oxidized to zinc oxide during this process.

Crystal Structural Studies of ZnO Nanorods and their Band Gaps

2014 ◽  
Vol 938 ◽  
pp. 71-75
Author(s):  
Muhd Firdaus Kasim ◽  
Norlida Kamarulzaman ◽  
Suraya Ahmad Kamil
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Zno Nanorods ◽  
Chelating Agent ◽  
Band Gaps ◽  
Zinc Oxide Nanostructures ◽  
X Ray Diffraction ◽  
Soft Chemistry ◽  
Oxide Nanostructures ◽  
Vis Spectroscopy

Zinc oxide nanostructures have been done by many scientists but amongst the soft chemistry methods, chelating agents are normally used. In this work zinc oxide nanostructures have been synthesized using a soft chemistry method without using a chelating agent. The precursor were annealed at various temperatures of 400 °C, 500 °C, 600 °C, 700 °C, 800 °C and 1200 °C for 24 h. Nanostructures are found with rod-like shapes and they are compared with larger oval morphology. X-Ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), and UV-Vis spectroscopy were used for characterization. XRD results confirm that all peaks were pure and single phase without the presence of any impurities. It was found from electron microscopy results that the morphology of the materials annealed at 400 °C possesses nanorod shape and as the calcination temperature increases, the material consists of mixed rod, spherical and oval shapes. The aspect ratio of the materials decreases when the annealing temperature increases. The absorption edges of the materials annealed at higher temperatures show a red-shift implying that narrowing of the band gaps occur in the materials. Band gap were evaluated and found to be between 3.32 to 3.19 eV.

Optical anisotropy of near band-edge transitions in zinc oxide nanostructures

2009 ◽  
Vol 480 (1) ◽  
pp. 50-53 ◽  
Author(s):  
Ching-Hwa Ho ◽  
Jian-Shen Li ◽  
Yi-Jia Chen ◽  
Ching-Cherng Wu ◽  
Ying-Sheng Huang ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Optical Anisotropy ◽  
Band Edge ◽  
Near Band Edge ◽  
Zinc Oxide Nanostructures ◽  
Oxide Nanostructures

scholarly journals Growth of GaN Thin Film on Amorphous Glass Substrate by Direct-Current Pulse Sputtering Deposition Technique

Coatings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 419 ◽  
Author(s):  
Wei-Sheng Liu ◽  
Yu-Lin Chang ◽  
Hui-Yu Chen
Keyword(s):  
Electron Microscopy ◽  
Buffer Layer ◽  
Direct Current ◽  
Glass Substrate ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Sputtering Power ◽  
Amorphous Glass ◽  
Zno Buffer Layer ◽  
Gan Film

We deposited 300-nm-thick GaN films on an amorphous glass substrate at a substrate temperature of 300 °C by using pulsed direct current (DC) sputtering. A ZnO buffer layer was utilized to improve the crystalline quality of the GaN films. Scanning electron microscopy results showed that the GaN thin films were grown along the c-axis and possessed a columnar structure. Atomic force microscopy results revealed that the GaN film deposited at a sputtering power of 75 W had the maximum grain size (24.1 nm). Room-temperature photoluminescence measurement of the GaN films indicated an ultraviolet near-band-edge emission at 365 nm and a Zn impurity energy transition level at 430 nm. In addition, X-ray diffraction conducted on the GaN films revealed a predominant (002) hexagonal wurtzite structure. The GaN film deposited at the sputtering power of 75 W demonstrated a high optical transmittance level of 88.5% in the wavelength range of 400–1100 nm. The material characteristics of the GaN films and ZnO buffer layer were studied using cross-sectional high-resolution transmission electron microscopy. The deposition of GaN films by using pulsed DC magnetron sputtering can result in high material quality and has high potential for realizing GaN-related optoelectronic devices on glass substrates.

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