scholarly journals Influence of Colloidal Au on the Growth of ZnO Nanostructures

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 870
Author(s):  
Frank Güell ◽  
Andreu Cabot ◽  
Sergi Claramunt ◽  
Ahmad Ostovari Moghaddam ◽  
Paulina R. Martínez-Alanis
Keyword(s):  
Gas Flow ◽  
Growth Parameters ◽  
Zno Nanowires ◽  
Au Nanoparticle ◽  
Broad Emission Band ◽  
Visible Range ◽  
Exciton Peak ◽  
Zno Nanostructures ◽  
Nanoparticle Suspension ◽  
Colloidal Au

Vapor-liquid-solid processes allow growing high-quality nanowires from a catalyst. An alternative to the conventional use of catalyst thin films, colloidal nanoparticles offer advantages not only in terms of cost, but also in terms of controlling the location, size, density, and morphology of the grown nanowires. In this work, we report on the influence of different parameters of a colloidal Au nanoparticle suspension on the catalyst-assisted growth of ZnO nanostructures by a vapor-transport method. Modifying colloid parameters such as solvent and concentration, and growth parameters such as temperature, pressure, and Ar gas flow, ZnO nanowires, nanosheets, nanotubes and branched-nanowires can be grown over silica on silicon and alumina substrates. High-resolution transmission electron microscopy reveals the high-crystal quality of the ZnO nanostructures obtained. The photoluminescence results show a predominant emission in the ultraviolet range corresponding to the exciton peak, and a very broad emission band in the visible range related to different defect recombination processes. The growth parameters and mechanisms that control the shape of the ZnO nanostructures are here analyzed and discussed. The ZnO-branched nanowires were grown spontaneously through catalyst migration. Furthermore, the substrate is shown to play a significant role in determining the diameters of the ZnO nanowires by affecting the surface mobility of the metal nanoparticles.

scholarly journals Nanofabrication using home-made RF plasma coupled chemical vapour deposition system

2014 ◽  
Vol 32 ◽  
pp. 1460342
Author(s):  
Si Ci Ong ◽  
Usman Ilyas ◽  
Rajdeep Singh Rawat
Keyword(s):  
Chemical Vapour ◽  
Chemical Vapor ◽  
Wide Band ◽  
Zno Nanowires ◽  
Operating Conditions ◽  
Rf Plasma ◽  
Zno Nanostructures ◽  
Energetic Ions ◽  
Cvd Method ◽  
Etching Effect

Zinc oxide, ZnO , a popular semiconductor material with a wide band gap (3.37 eV) and high binding energy of the exciton (60 meV), has numerous applications such as in optoelectronics, chemical/biological sensors, and drug delivery. This project aims to (i) optimize the operating conditions for growth of ZnO nanostructures using the chemical vapor deposition (CVD) method, and (ii) investigate the effects of coupling radiofrequency (RF) plasma to the CVD method on the quality of ZnO nanostructures. First, ZnO nanowires were synthesized using a home-made reaction setup on gold-coated and non-coated Si (100) substrates at 950 °C. XRD, SEM, EDX, and PL measurements were used for characterizations and it was found that a deposition duration of 10 minutes produced the most well-defined ZnO nanowires. SEM analysis revealed that the nanowires had diameters ranging from 30-100 mm and lengths ranging from 1-4 µm. In addition, PL analysis showed strong UV emission at 380 nm, making it suitable for UV lasing. Next, RF plasma was introduced for 30 minutes. Both remote and in situ RF plasma produced less satisfactory ZnO nanostructures with poorer crystalline structure, surface morphology, and optical properties due to etching effect of energetic ions produced from plasma. However, a reduction in plasma discharge duration to 10 minutes produced thicker and shorter ZnO nanostructures. Based on experimentation conducted, it is insufficient to conclude that RF plasma cannot aid in producing well-defined ZnO nanostructures. It can be deduced that the etching effect of energetic ions outweighed the increased oxygen radical production in RF plasma nanofabrication.

Tailored Si-Layers on Silicon Oxide Obtained by Thermal CVD

1997 ◽  
Vol 485 ◽  
Author(s):  
G. Beaucarne ◽  
J. Poortmans ◽  
M. Caymax ◽  
J. Nijs ◽  
R. Mertens
Keyword(s):  
Gas Flow ◽  
Silicon Solar Cell ◽  
Silicon Oxide ◽  
Crystalline Silicon ◽  
Growth Parameters ◽  
Nucleation Theory ◽  
Crystalline Silicon Solar Cell ◽  
Qualitative Explanation ◽  
Nucleus Density ◽  
Thermal Cvd

AbstractIn this paper, a method to obtain by CVD Si layers on silicon oxide with the desired grain size is described, involving nucleation control through the growth parameters. Nucleation experiments are carried out with a hydrogen - dichlorosilane - HCl ambient at high temperature. The nucleus density is observed to drop to low values at a threshold HCl-flow. A qualitative explanation using concepts from atomistic nucleation theory is proposed. The effect of addition of diborane to the gas flow is investigated and appears to be small or non-existent . Finally, preliminary results of a thin-film crystalline silicon solar cell process applied on such layers are given to illustrate the potential of such layers.

scholarly journals Extracting structural information of Au colloids at ultra-dilute concentrations: identification of growth during nanoparticle immobilization

2019 ◽  
Vol 1 (7) ◽  
pp. 2546-2552 ◽  
Author(s):  
George F. Tierney ◽  
Donato Decarolis ◽  
Norli Abdullah ◽  
Scott M. Rogers ◽  
Shusaku Hayama ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Structural Characterization ◽  
Structural Information ◽  
Particle Growth ◽  
Au Nanoparticle ◽  
X Ray ◽  
Colloidal Au ◽  
X Ray Absorption ◽  
Au Colloids

This paper describes the structural characterization of ultra-dilute colloidal Au nanoparticle solutions using X-ray absorption spectroscopy (XAS) and the particle growth during immobilization.

Synthesis of ZnO Nanowires by Hydrothermal Technique for Integration Into Chalcopyrite Thin Films

2012 ◽  
Vol 1406 ◽  
Author(s):  
H. Karaagac ◽  
M. Parlak ◽  
M. Saif Islam
Keyword(s):  
Thin Film ◽  
Solar Cell ◽  
Seed Layer ◽  
Growth Parameters ◽  
Vertical Direction ◽  
Zno Nanowires ◽  
Growth Time ◽  
Silicon Substrates ◽  
Transmission Measurement ◽  
Hydrothermal Technique

ABSTRACTVertically oriented, highly dense ZnO nanowires (NWs) array was successfully grown on both glass and silicon substrates using hydrothermal technique. A systematic study was carried out to investigate the effects of growth parameters including growth time and thickness of ZnO seed layer on the quality of ZnO NWs in terms of their homogeneity and orientation in the vertical direction. The diameter as well as the length of grown ZnO NWs was found to be closely dependent on the thickness of the pre-coated ZnO seed layer. The structures of ZnO NWs and electron-beam evaporated AgGa0.5In0.5Se2 (AGIS) thin film have been characterized by X-ray diffraction measurements and optical properties were measured by transmission measurement. The optic band gap of AGIS thin film was found to be almost optimum (1.56 eV) to match the abundant part of solar cell spectrum. AGIS thin film was deposited on the synthesized ZnO NWs to form p-n heterojunction based inorganic solar cell, which exhibited photovoltaic behavior with a power conversion efficiency of 0.37 % under A.M (1.5) illumination.

A Surface-Enhanced Resonance Raman Scattering Method for the Determination of Trace Crystal Violet on Colloidal Au Nanoparticle Substrate

2013 ◽  
Vol 299 ◽  
pp. 191-194 ◽  
Author(s):  
Zhi Liang Jiang ◽  
Lu Ma ◽  
Ai Hui Liang
Keyword(s):  
Raman Scattering ◽  
Crystal Violet ◽  
Resonance Raman ◽  
Trisodium Citrate ◽  
Au Nanoparticle ◽  
Scattering Method ◽  
Resonance Raman Scattering ◽  
Buffer Solution ◽  
Surface Enhanced ◽  
Colloidal Au

Colloidal Au nanoparticles as active substrate for surface-enhanced resonance Raman scattering(SERRS) were prepared by the trisodium citrate-reduced procedure. In pH 6.6 Na2HPO4-NaH2PO4 buffer solution and in the presence of aggregation reagent NaCl, nanogolds were aggregated to form stable aggregated- nanogolds (ANG). The crystal violet (CV) adsorbed on the surface of ANG to form CV-ANG conjugates that produce strongest surface-enhanced resonance Raman scattering peak at 1616 cm-1. In the optimal condition, the SERRS intensity at 1616 cm-1 was linear to the CV concentration in the range of 2.5×10-8 -1.75×10-7 mol/L, a surface-enhanced resonance Raman scattering assay was set up for detection of trace CV, with good selectivity.

scholarly journals Influence of the Hydrothermal Method Growth Parameters on the Zinc Oxide Nanowires Deposited on Several Substrates

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Concepción Mejía-García ◽  
Elvia Díaz-Valdés ◽  
Marco Alberto Ayala-Torres ◽  
Josué Romero-Ibarra ◽  
Máximo López-López
Keyword(s):  
Growth Parameters ◽  
Zinc Acetate Dihydrate ◽  
Band Gap Energy ◽  
Zinc Nitrate ◽  
Zno Nanowires ◽  
Nitrate Hexahydrate ◽  
Oxide Nanowires ◽  
Si Substrates ◽  
Glass Substrates ◽  
Xrd Patterns

We report the synthesis of ZnO nanowires grown on several substrates (PET, glass, and Si) using a two-step process: (a) preparation of the seed layer on the substrate by spin coating, from solutions of zinc acetate dihydrate and 1-propanol, and (b) growth of the ZnO nanostructures by dipping the substrate in an equimolar solution of zinc nitrate hexahydrate and hexamethylenetetramine. Subsequently, films were thermally treated with a commercial microwave oven (350 and 700 W) for 5, 20, and 35 min. The ZnO nanowires obtained were characterized structurally, morphologically, and optically using XRD, SEM, and UV-VIS transmission, respectively. XRD patterns spectra revealed the presence of Zn(OH)2on the films grown on glass and Si substrates. A preferential orientation alongc-axisdirections for films grown on PET substrate was observed. An analysis by SEM revealed that the growth of the ZnO nanowires on PET and glass is better than the growth on Si when the same growth parameters are used. On glass substrates, ZnO nanowires less than 50 nm in diameter and between 200 nm and 1200 nm in length were obtained. The ZnO nanowires band gap energy for the films grown on PET and glass was obtained from optical transmission spectra.

Growth of High Quality Poly-SiGe on Glass Substrates

1996 ◽  
Vol 452 ◽  
Author(s):  
Kunihiro Shiota ◽  
Daisuke Inoue ◽  
Kouichirou Minami ◽  
Masaji Yamamoto ◽  
Jun-ichi Hanna
Keyword(s):  
Electron Microscopy ◽  
Gas Flow ◽  
Growth Parameters ◽  
Substrate Surface ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Glass Substrates ◽  
Transmission Electron ◽  
Composition Variation ◽  
Gas Flow Ratio

AbstractThe composition variation and strutural properties of poly-SiGe thin films were investigated by Reactive Thermal CVD with Si2H6 and GeF4. Deposition of the films was carried out at a low temperature of 450°C on oxidized silicon substrates using different growth parameters, i.e., the source gas flow ratio (Si2H6/ GeF4) and thegas flow rate. The structural profiles of as-deposited films were characterized by X-ray diffraction (XRD) and Raman scattering spectroscopies, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).All these films show (220) preferential orientation. The mole fractions of Si in poly-SixGe1−x films were estimated to be from 0.95 to 0.05 for x by using Vegard's law for the XRD peaks. TEM observation revealed that high crystallinity was well established even in poly-Si0.95Ge0.05 films owing to the direct nucleation on the substrate surface.

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