Effect of Surfactants on the Morphologies of ZnO Nanostructures Synthesized by Hydrothermal Method and its Gas Sensitivity to Formaldehyde

2010 ◽  
Vol 159 ◽  
pp. 628-633 ◽  
Author(s):  
Kai Jin Huang ◽  
Li Yan ◽  
Chang Sheng Xie
Keyword(s):  
Citric Acid ◽  
Polyvinyl Alcohol ◽  
Hydrothermal Method ◽  
Zno Nanorods ◽  
Alumina Substrate ◽  
Zno Nanostructures ◽  
Growth Mechanisms ◽  
Gas Sensitivity ◽  
Nano Zno ◽  
Zno Nanosheets

Based on the principle of the higher surface-to-volume ratios, the higher formaldehyde gas sensitivity, different morphologies’s ZnO nanostructures have been synthesized by hydrother- mal method using different surfactants including polyvinyl alcohol (PVA), cetyltrimethyl ammon- ium bromide (CTAB), sodium tripolyp hosphate (STPP) and citric acid(CA). The crystal structur- es and morphologies were characterized by XRD and FESEM. The results show that different morphologies’s ZnO nanostructures were induced on the surface of alumina substrate, and the surfactants had an important effect on the morphologies of ZnO nanostructures and then affected the formaldehyde gas sensitivity. The ZnO nanorods with diameters of 100-500 nm and lengths of 200-900nm were obtained using PVA surfactant. The ZnO nanosheets with thickness of about 10nm were obtained using CTAB surfactant. The ZnO nanodisks with two layers and thickness of 5-10nm were obtained using STPP surfactant. The ZnO microspheres composed of thin flakes with thickness of about 10 nm were obtained using CA surfactant. The growth mechanisms of different morphologies’s ZnO nanostructures using different surfactants were given in detail. In addition, the formaldehyde gas sensitivities of different morphologies’s ZnO nanostructures were measured and showed the higher formaldehyde gas sensitivity compared with nano-ZnO without surfactant.

EFFECTS OF Au ON THE GROWTH OF ZnO NANOSTRUCTURES ON Si BY MOCVD

2013 ◽  
Vol 06 (04) ◽  
pp. 1350044
Author(s):  
CHEN CONG ◽  
LU YANG FAN ◽  
HE HAI PING ◽  
WU KE WEI ◽  
YE ZHI ZHEN
Keyword(s):  
Low Temperature ◽  
Au Nanoparticles ◽  
Critical Role ◽  
Zno Nanorods ◽  
Crystalline Quality ◽  
Organic Chemical ◽  
Zno Nanostructures ◽  
Gaseous Species ◽  
Nano Zno

The effects of Au on the growth of ZnO nanostructures on Si by metal organic chemical vapor deposition (MOCVD) at a relatively low temperature (450°C) were investigated. The experimental results showed that Au nanoparticles played a critical role during the growth of the ZnO nanostructures and affected their morphology and optical properties. It was found that Au nanoparticles particularly affected the nucleation of ZnO nanostructures during the growth process and the Au -assisted growth mechanism of ZnO nanostructures should be ascribed to the vapor–solid (VS) mechanism. The formation of a nanoneedle may be attributed to a more reactive interface between Au and ZnO , which leads to more zinc gaseous species absorbed near the interface. Different nucleation sites on ZnO nuclei resulted in the disorder of ZnO nanoneedles. Moreover, the crystalline quality of nano- ZnO was improved due to the presence of Au , according to the smaller full width at half maximum (FWHM) of the low-temperature exciton emission. We confirmed that ZnO nanoneedles showed better crystalline quality than ZnO nanorods through the HRTEM images and the SAED patterns. The reason for the improvement of the crystalline quality of nano- ZnO may be due to the less lattice mismatch.

Gas Sensitivity of MnO2 Doped Nano ZnO Coplanar Plate-Type Gas Sensor Arrays

2010 ◽  
Vol 159 ◽  
pp. 634-637 ◽  
Author(s):  
Kai Jin Huang
Keyword(s):  
Hydrothermal Method ◽  
Gas Sensor ◽  
Screen Printing ◽  
Sensor Arrays ◽  
Large Specific Surface Area ◽  
Zno Film ◽  
Gas Sensitivity ◽  
Nano Zno ◽  
Plate Type ◽  
Gas Sensor Arrays

Based on the integrated technologies of screen printing and hydrothermal method, this paper introduced a new integrative method with materials microstructure controlled growth and gas sensor fabrication. For example,based on space positioning using screen printing and ZnO nanwall with large specific surface area induced by hydrothermal method on the surface of ZnO film, the MnO2 doped nano ZnO coplanar plate-type gas sensor arrays with a good gas sensitivity to formaldehyde were fabricated successfully. The results show that the sensitivity to formaldehyde of MnO2 doped nano ZnO gas sensor arrays fabricated by hydrothermal method in 0.01mol/L Zn(NO3)2 solution, 95°C for 5h on the surface of MnO2 doped nano ZnO film and sintering at 500°C for 2h is higher than that of in distilled water. The existence of ZnO nanwall with large specific surface area induced by hydrothermal method on the surface of MnO2 doped nano ZnO film is the important reason of improvement for the sensitivity to formaldehyde.

Effect of Addition of KI on the Hydrothermal Growth of ZnO Nanostructures Towards Hybrid Optoelectronic Device Applications

2016 ◽  
Vol 16 (4) ◽  
pp. 3301-3306 ◽  
Author(s):  
Anubha Bilgaiyan ◽  
Tejendra Dixit ◽  
Gaurav Kapil ◽  
Shyam S Pandey ◽  
Shuji Hayase ◽  
...  
Keyword(s):  
Defect Density ◽  
Zno Nanorods ◽  
Optoelectronic Device ◽  
Hydrothermal Growth ◽  
Visible Range ◽  
Zno Nanostructures ◽  
X Ray Diffraction ◽  
Zno Nanosheets ◽  
Device Applications ◽  
Structural And Optoelectronic Properties

We report the structural and optoelectronic properties of Zinc oxide (ZnO) nanostructures prepared by hydrothermal method. The morphological, structural and optical properties of the grown ZnO nanostructures were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence spectroscopy (PL) respectively. Upon addition of relatively small amount of KI during the in-situ hydrothermal growth the nanorods were formed, further increasing the concentration led to increased diameter of these nanorods and finally at relatively higher concentration of KI, ZnO nanosheets were formed. Later these structures were used to fabricate bi-layer ZnO/P3HT based hybrid photodiode. Subsequent hybrid photodiode measurement with ZnO nanorods and ZnO nanosheets indicated that the nanosheets exhibited improved photodiode response. Compared to the ZnO nanorod/P3HT devices, the optimized photodiode with the dense ZnO nanosheets/P3HT have shown significant increase in the rectification ratio and the photosenstivity from 3.21 to 1420 and from 5.85 to 1330 respectively. The enhanced photodiode response of bi-layered devices consisting of ZnO nanosheets indicated that optimizing the shape and size of ZnO nanostructures had a significant influence on the overall photocurrent and the observed results have been explained on the basis of reduction in the defect density with pronounced absorption in the UV region, thus leading to improved transmission of light in the visible range through these layers.

SHAPE EVOLUTION IN ONE-DIMENSIONAL ZnO NANOSTRUCTURES GROWN FROM ZnO NANOPOWDER SOURCE: VAPOR–LIQUID–SOLID VERSUS VAPOR–SOLID GROWTH MECHANISMS

2011 ◽  
Vol 10 (01n02) ◽  
pp. 75-79 ◽  
Author(s):  
SOUMEN DHARA ◽  
P. K. GIRI
Keyword(s):  
Growth Mechanism ◽  
Growth Temperature ◽  
Shape Evolution ◽  
Zno Nanostructures ◽  
Growth Mechanisms ◽  
Vapor Liquid Solid ◽  
One Dimensional ◽  
Zno Nanopowder ◽  
Simultaneous Growth ◽  
Vapor Liquid

Here we report on the growth and evolution of ZnO nanowires grown from ZnO nanopowder as a source material using a horizontal muffle furnace. The shape evolution has been studied with variation in growth temperature and zinc vapor pressure. The structural analysis on these nanostructures shows c-axis oriented aligned growth. Scanning electron microscopy imaging of these nanostructures revealed the shape evolution from nanowires to nanoribbons and then to nanorods as the growth temperature increases from 650°C to 870°C. At 650°C, only vertical nanowires have been observed and with increase in growth temperature nanowires transform to nanoribbons and then to nanorods at 870°C. And we also observed simultaneous growth of nanorods and nanoribbons under a specific growth condition. We believe that these nanowires and nanorods were formed by vapor–liquid–solid growth mechanism (catalyst-mediated growth), whereas nanoribbons were grown by vapor–solid growth mechanism (without the aid of a metal catalyst). We observed simultaneous occurrence of vapor–liquid–solid and vapor–solid growth mechanisms at a particular growth temperature. These ZnO nanowires exhibit bound exciton related UV emission at ~379 nm, and defect-emission band in the visible region. Possible growth mechanism, shape evolution, and simultaneous growth of two types of one-dimensional ZnO nanostructures under the same growth condition are discussed.

scholarly journals Synthesis of Ga-Doped ZnO Nanorods by Hydrothermal Method and Their Application to Ultraviolet Photodetector

Inventions ◽  
2016 ◽  
Vol 1 (1) ◽  
pp. 3 ◽  
Author(s):  
Sheng-Joue Young ◽  
Chia-Lin Chiou ◽  
Yi-Hsing Liu ◽  
Liang-Wen Ji
Keyword(s):  
Hydrothermal Method ◽  
Zno Nanorods ◽  
Ultraviolet Photodetector ◽  
Doped Zno

scholarly journals Studies on the Growth Control of ZnO Nanostructures synthesized by the Chemical Method

2018 ◽  
Vol 23 (2) ◽  
Author(s):  
Patricia María Perillo ◽  
Mariel Nahir Atia ◽  
Daniel Fabián Rodríguez
Keyword(s):  
Chemical Method ◽  
Morphological Evolution ◽  
Zno Nanorods ◽  
Growth Control ◽  
Zno Nanostructures ◽  
X Ray Diffraction ◽  
Wurtzite Phase ◽  
X Ray ◽  
Hexagonal Wurtzite Phase

ABSTRACT ZnO nanostructures were synthesized through a chemical method using different Zn precursors and hexamethylenetetramine (HMTA) at 90 °C. The effects of the reactants on the morphological evolution of ZnO nanorods were investigated. The samples were characterized by using XRD, SEM, EDX and BET. The hexagonal wurtzite phase of ZnO was confirmed by X-ray diffraction (XRD). The performed analysis indicated that different morphologies were obtained by changing the reactants.

Novel fabrication of various size ZnO nanorods using hydrothermal method

2010 ◽  
Vol 87 (5-8) ◽  
pp. 1534-1536 ◽  
Author(s):  
Seong-Jong Kim ◽  
Han-Hyoung Kim ◽  
Joo-Beom Kwon ◽  
Jong-Geun Lee ◽  
Beom-Hoan O ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Zno Nanorods
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