Papers by Keyword: ZnO Nanostructures

Abstract: Sol-gel precursor has been prepared by using zinc acetate (ZnAC) as starting material dissolved in isopropanol (IPA), diethanolamine (DEA) and distilled water (H₂O) were added to produce a homogeneous and stable solution. The sol-gel precursor was deposited on ITO/PET substrate by spin-coat route. Oxidation process was held in deionized water at 90 °C for a specific time. The (100) and (101) ZnO planes were formed as the preferred orientation. RMS values of ZnO samples found to be 280 nm, 272 nm and 241 nm for 8 h, 12 h and 16 h, respectively by hot water treatment (HWT). ZnO nanorods-hourglass-like, nanosheet-leafs-like and nanorods-oval-like were obtained with different HWT time.

Abstract: In this work, seeded porous silicon (PSi) was used as a substrate in the growth of ZnO nanostructures. PSi was prepared by electrochemical etching method. ZnO thin films as seeded were deposited via sol-gel spin coating method. ZnO nanostructures were grown on seeded PSi using hydrothermal immersion method. In order to study the effect of post-heat treatment on the substrate, post annealing temperature were varied in the range of 300 to 700 °C. The FESEM results shows ZnO thin film composed of nanoparticles were distributed over the PSi surface. Based on AFM characterization, the smoothest surface was produced at post annealing temperature of 500 °C. There are two different peaks appeared in PL characterization. The peak in near-UV range is belonging to ZnO thin films while a broad peak in visible range can be attributed to ZnO defects and PSi surface. In addition, FESEM, XRD and PL were used to characterize the ZnO nanostructures. The FESEM results revealed ZnO nano-flower were successfully grown on seeded PSi. Hexagonal wurtzite of ZnO with dominated by the plane (100), (002), and (101) was found by XRD characterization. Two different peaks in UV range and visible range can be attributed to ZnO nano-flower and various defects of ZnO, respectively.

Abstract: In the present work, ZnO nanostructures were synthesized via wet chemistry method. The seeding solution was prepared from zinc nitrate tetrahydrate and hexamethylenetetramine. Prior to the heating process, the seeding solution was immersed in cold bath (0°C). XRD analysis had shown sharp peaks in diffractogram, indicating the high crystallinity of ZnO nanostructures. The crystallite size was determined using Scherrer equation and Williamson-Hall method. Other relevant parameters including stress, strain, and energy density were calculated using Williamson-Hall assuming UDM, UDSM, and UDEDM. The results had revealed that crystallite size calculated with Williamson-Hall method is more accurate than Scherrer equation.

Abstract: Mist-atomization deposition method was applied in order to grow ZnO nanostructures with various surface morphologies. ZnO was deposited from the mixture of zinc nitrate hexahydrate (Zn (NO₃)₂.6H₂O) and stabilizer, hexamethylenetetramine (HMTA, C₆H₁₂N₄) aqueous solutions onto Au-seeded glass substrate. The mixture was sprayed onto the surface of Au-seeded glass substrate at various growth temperatures of room temperature (RT), 100, 200, and 300 °C. The obtained structures were characterised by room-temperature photoluminescence (PL), field emission scanning electron microscopy (FESEM), and UV-VIS-NIR spectrophotometer. It is found that ZnO growth on 300 °C substrate temperature shows the best absorbance properties and highest UV emission peak with denser distribution amongst all. The optical and morphological properties of sprayed ZnO nanostructures largely depend on the substrates temperature during spraying the zinc nitrate solution and on the Au-seeded glass substrates.

Abstract: ZnO nanostructures were obtained by mist-atomisation technique. Nanostructured ZnO can be grown in aqueous solution of zinc nitrate hexahydrate as precursor solution with the addition of stabilizer hexamethylenetetramine (HMTA). ZnO nanostructures deposited by mist-atomisation, with applied heat from the glass substrates’ downside. Firstly, the glass substrates were seeded by Au with different thickness of 0 (non-seeded), 6, and 12 nanometer (nm). The growth of ZnO on different Au-seeded thickness is studied. The optical properties of ZnO nanostructures were examined by Ultraviolet-Visible (UV-Vis) spectroscopy. The morphology of the ZnO thin films obtained was studied by FESEM. FESEM micrographs shows different nanostructures formed on different thickness of Au-seeded glass. UV-vis spectra of ZnO nanostructures display high absorption in the UV region and high transparency in the visible region. There is improvement in UV absorption for ZnO growth on 6nm Au-seeded compared to non-seeded and 12 nm Au-seeded glass due to imperfect alignment of ZnO nanostructures.

Abstract: In this study, ZnO nanostructures were synthesized on porous silicon (PSi) substrate using hydrothermal immersion method. Different post-annealing temperatures were varied from 300°C to 600°C. Surface morphology was studied by field emission scanning electron microscopy. It shows that a better shape was produce at annealing temperatures of 500°C. Structural studies of ZnO nanostructure were implemented using X-ray diffraction grating. The result shows post-annealing can influence the crystallinty of ZnO. Photoluminescence spectra were used to study the optical properties of ZnO nanostructure. The result shows that peak corresponds to ZnO nanostructures are appeared in UV range. Besides, broad peaks are also appeared in visible range which is attributed to structural defects and PSi substrate.

Abstract: Zinc coated mild steel is usually applied to protect the substrate surface from corrosion. In this study, Zinc Oxide nanostructure layer will be used to protect the surface of mild steel from corrosion. The Zinc Oxide nanostructure will be synthesized by sol-gel method. After the solution was prepared, it then coated on mild steel surface using spin coater and anneal at different temperature to see the growth of Zinc Oxide nanostructures. After the sample has been coated it will characterize using FESEM, XRD and LPR.

Abstract: Monodispersed polyvinylpyrrolidone capped nanostructures of zinc oxide are prepared through chemical precipitation technique. The prepared nanostructures are characterized by XRD, SEM and Photoluminescence spectroscopic techniques. X-ray diffraction studies confirm the hexagonal structure of zinc oxide nanostructures. Nanostructures of the prepared zinc oxide are confirmed by SEM. The emission wavelength of PVP capped zinc oxide is found to be 551 nm using photoluminescence spectra.

Abstract: The morphologies of ZnO nanostructured were synthesized by carbon assisted. The materials source will be prepared by mixing Zn, ZnO and coconut shell charcoal or graphite. The materials source and silicon substrates were put in quartz tube of furnace, heated in difference gases. When, the temperature was cooled down to natural room temperature. The materials sources and silicon substrates will be studied by scanning electron microscope (SEM) and an energy dispersive X-rays instrument (EDX). The results showed that ZnO nanostructures materials such as nanotatrapods, nanowires, nanorods and nanoparticles can be observed.

Abstract: Zinc oxide (ZnO) presents several applications as piezoelectric transducers, photosensors, solar cells, electrochemical sensors, etc. Electrodeposition of zinc oxide (ZnO) thin films from aqueous solution of zinc nitrate has been deposited in graphenated low cost pencil graphite. The electrochemical graphene production at the tips was performed in a low cost DC source using concentrated sulfonitric solution. The tips were expanded in hydrogen plasma and treated by oxygen plasma to enhance its hydrophilicity. The posterior ZnO electrodeposition was highly efficient and the graphene functionalization contributes to overall electrochemical deposition mechanism.