Seed layer morphology influencing on ZnO nanorod growth by hydrothermal synthesis (original) (raw)
Related papers
Peculiarity of seed-layer synthesis and morphometric characteristics of ZnO nanorods
Eastern-European Journal of Enterprise Technologies, 2014
Представлено оригінальні результати синтезу нанострижнів ZnO за допомогою низькотемпературних методів на підкладках ніобату літію. Вперше продемонстровано «орієнтовані канали», які виникають після відпалу зародкового шару при температурі 400°С і свідчать про початок процесу кристалізації. Проаналізовано вплив властивостей зародкового шару ZnO, сформованого золь-гель методом, на морфометричні характеристики синтезованих гідротермальним методом нанострижнів Ключові слова: зародковий шар, зольгель, гідротермальний метод, нанострижні ZnO Представлены оригинальные результаты синтеза наностержней ZnO с помощью низкотемпературных методов на подложках ниобата лития. Впервые продемонстрированы «ориентированные каналы», которые возникают после отжига зародышевого слоя при температуре 400°С и свидетельствуют о начале процесса кристаллизации. Проанализировано влияние свойств зародышевого слоя ZnO, сформированного золь-гель методом, на морфометрические характеристики синтезированных гидротермальным методом наностержней Ключевые слова: зародышевый слой, золь-гель, гидротермальный метод, наностержни ZnO УДК 539.23
Highly Textured Seed Layers for the Growth of Vertically Oriented ZnO Nanorods
Crystals, 2019
One dimensional ZnO nanostructures prepared by favorable and simple solution growth methods are at the forefront of this research. Vertically oriented ZnO nanorods with uniform physical properties require high-quality seed layers with a narrow size distribution of the crystallites, strong c-axis orientation, and low surface roughness and porosity. It has been shown that high quality seed layers can be prepared by the sol–gel process. The sol–gel process involves three essential steps: preparation of the sol, its deposition by dip coating, and thermal treatment comprising preheating and annealing. We put emphasis on the investigation of the heat treatment on the properties of the seed layers and on the vertical alignment of the nanorods. It was demonstrated that for the vertical alignment of the nanorods, the preheating step is crucial and that the temperatures reported in the literature have been too low. With higher preheating temperatures, conditions for the vertical alignment of ...
Growth of ZnO nanorods on different substrates using hydrothermal method
Malaysian Journal of Fundamental and Applied Sciences, 2020
Zinc oxide (ZnO) nanorods have been grown on different substrates, i.e. gold film-coated BK-7 glass (Au-film/BK7), microscope glass slide (MGS), silicon oxide film-coated silicon (SiO2-film/Si), to investigate the effects of different substrates on its material properties. The growth process was started by dipping substrates in zinc acetate solution to fabricate a seed layer, followed by growing the ZnO nanorods in zinc nitrate tetrahydrate solution based on hydrothermal method at 95 °C for 6 hour. In this process, seed layer and ZnO nanorods were annealed at 350 °C for 2 hours. The characterization results using X-ray diffraction and field effect scanning electron microscope showed that ZnO nanorods were successfully grown homogenously and mostly in vertical direction with hexagonal wurtzite structure. The diameter size of ZnO nanorods was significantly influenced by the type of material substrate. ZnO nanorods on Au-film/BK-7 glass have the smallest diameter size of (239±51) nm, w...
Materials, 2013
Well aligned ZnO nanorods have been prepared by a low temperature aqueous chemical growth method, using a biocomposite seed layer of ZnO nanoparticles prepared in starch and cellulose bio polymers. The effect of different concentrations of biocomposite seed layer on the alignment of ZnO nanorods has been investigated. ZnO nanorods grown on a gold-coated glass substrate have been characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) techniques. These techniques have shown that the ZnO nanorods are well aligned and perpendicular to the substrate, and grown with a high density and uniformity on the substrate. Moreover, ZnO nanorods can be grown with an orientation along the c-axis of the substrate and exhibit a wurtzite crystal structure with a dominant (002) peak in an XRD spectrum and possessed a high crystal quality. A photoluminescence (PL) spectroscopy study of the ZnO nanorods has revealed a conventional near band edge ultraviolet emission, along with emission in the visible part of
Journal of Nanoscience and Nanotechnology, 2012
We report the structural properties of the vertically-oriented ZnO nanorods fabricated on various ZnO seed layers with chemical solution deposition (CSD) technique. The ZnO nanorods were prepared using an aqueous solution with Zinc nitrate (Zn(NO 3 2 • 6H 2 O, Aldrich) and hexamethylenetetramine (HMT, Aldrich) in a convection oven. A-plane sapphire substrates with a deposited ZnO thin film were placed upside down in a quartz holder to avoid any micro-crystalline contamination. Especially, our hydro-thermal syntheses are automatically processed on precision pump drive systems (Masterflex) to accurately control the pH of the aqueous solution. The [002] crystal orientation of the ZnO seed layer was observed by the X-ray diffraction pattern. Structural features of ZnO nanorods were systematically analyzed by scanning electron microscopy and tunneling electron microscopy, together with selective area electron diffraction patterns. Experimental observations clearly demonstrated the dependence of the growth direction of the ZnO nanorods on the crystal structures of the ZnO seed layers.
Effect of seeded substrates on hydrothermally grown ZnO nanorods
Journal of Sol-Gel Science and Technology, 2009
We report a study on the effect of seeding on glass substrates with zinc oxide nanocrystallites towards the hydrothermal growth of ZnO nanorods from a zinc nitrate hexahydrate and hexamethylenetetramine solution at 95°C. The seeding was done with pre-synthesized ZnO nanoparticles in isopropanol with diameters of about 6-7 nm as well as the direct growth of ZnO nanocrystallites on the substrates by the hydrolysis of pre-deposited zinc acetate film. The nanorods grown on ZnO nanoparticle seeds show uniform dimensions throughout the substrate but were not homogenously aligned vertically from the substrate and appeared like nanoflowers with nanorod petals. Nanorods grown from the crystallites formed in situ on the substrates displayed wide variations in dimension depending upon the preheating and annealing conditions. Annealing the seed crystals below 350°C led to scattered growth directions whereupon preferential orientation of the nanorods perpendicular to the substrates was observed. High surface to volume ratio which is vital for gas sensing applications can be achieved by this simple hydrothermal growth of nanorods and the rod height and rod morphology can be controlled through the growth parameters.
Characterisation of ZnO nanorod arrays grown by a low temperature hydrothermal method
Philosophical Magazine, 2012
In this paper, growth steps of well defined ZnO nanorod arrays deposited on seeded substrates were investigated. To obtain ZnO seed layer on glass substrates, a successive ionic layer adsorption and reaction (SILAR) method was used and then ZnO nanorods were grown on seed layer using a chemical bath deposition (CBD) method. The effects of seed layer and deposition time on morphology, crystallographic structure (e.g. grain size, microstrain and dislocation density) and electrical characteristics of ZnO nanorods were studied. From the SEM micrographs, it could be seen that the ZnO nanorods densely covered the substrate and were nearly perpendicular to the substrate surface. The XRD patterns showed that the ZnO nanorod arrays had a hexagonal wurtzite structure with a preferred orientation along the (002) plane. An increase in deposition time resulted in an increase in the intensity of the preferred orientation and grain size, but a decrease in microstrain and dislocation density. Electrical activation energies of the structures were calculated as 0.15-0.85 eV from current-temperature characteristics. It was concluded that the morphologies of the structures obtained in this study via a simple and fast solution method can provide high surface areas which are important in areadependent applications, such as solar cells, hydrogen conversion devices, sensors, etc.
2017
ZnO nanorods were prepared by a hybrid deposition technique. ZnO seed layers were deposited onto glass substrates by sol-gel spin coating technique. ZnO nanorods were synthesized onto seed layers by chemical bath deposition method in very short time like 30 minutes. Effects of seed layer and the thickness of the seed layer on the crystalline structure and morphology of the ZnO nanorods were investigated using X-ray diffractometer (XRD) and field emission scanning electron microscope (FESEM). It was established that ZnO nanorod does not form without seed layer. It was found that ZnO nanorods synthesized onto seed layer have a perfect crystalline wurzite structure with a preferentially orientation of (002). The intensity of (002) peak strongly increased as the thickness of seed layer increased. It was determined that the majority of synthesized ZnO nanorods on the seed layers are vertical. An increase was observed in the density and the length of the vertically synthesized ZnO nanorods by increasing the thickness of seed layer. The increased thickness of seed layers led to improve the crystalline quality and morphological properties of ZnO nanorods.
Hydrothermal Growth of Vertical ZnO Nanorods
Journal of The American Ceramic Society, 2009
Vertically aligned, single crystalline ZnO nanorods with a high packing density and diameter of ∼60 nm have been successfully synthesized via a low-temperature hydrothermal route on glass substrates pre-deposited with a ZnO seeding layer. The seeding layer exhibits an epitaxial effect on the growth and alignment of the ZnO nanorods. This epitaxial effect can arise from two considerations, namely the crystalline orientation and surface roughness of the seeding layer, which can be controlled by the curing temperature. The ZnO seeding layer that was cured at 350°C exhibited a preferred (0002) crystalline orientation of wurtzite hexagonal structure and a low surface roughness. It was demonstrated to promote the vertical growth of ZnO nanorods. The ZnO nanorods grew in an almost linear relationship with hydrothermal time up to 8 h, but thereafter started to dissolve as the reaction time extended beyond 8 h, due to competition from the homogeneous nucleation of ZnO microparticles in the solution.
Growth of Vertically Aligned ZnO Nanorods Arrays by Hydrothermal Method
Advanced Materials Research, 2013
Well-aligned ZnO nanorod arrays with different average diameters were grown on silicon(100) substrates by hydrothermal method via the precursors of zinc nitrate hexahydrate ((). 6) and Hexamethylenetetramine () with equal molar concentration at 0.025 mol/l and 0.05 mol/l. The ZnO nanorods were characterized by X-ray diffraction (XRD) and field emission Scanning electron microscopy (FE-SEM). XRD results indicated that all the ZnO nanorods were preferentially grown along [0001] direction (c-axis). field emission Scanning electron microscopy images showed that the well-faceted hexagonal ZnO nanorods were grown vertically from the silicon(100) substrates.