M. Z. Sahdan

Growth Pattern of Zinc Oxide Nanorods on Gold Coated Silicon Surfaces

Nanostructured ZnO nanorods on gold (Au) coated silicon (Si) surfaces were made by solution method immerse technique, using (ZnNO3)2/HMTA at 80° C. The seed surfaces of Au were sputter‐coated on Si substrates, in which Au thicknesses were affected by current and sputter‐coating time. The morphology of the prepared nanostructure was analysed by scanning electron microscope (SEM), and the structural identification of the ZnO nanorods was carried out using X‐ray diffraction in the range of 2θ between 30°–60°. The growth intensity of ZnO nanorods on the substrate was found to be consistent from 3 nm to 12 nm of Au, at 15 nm there is a tremendous drop in growth. The resulting (hkl) peaks were found to be lattice planes of (100), (002), (101), (102) and (110). The presence of Au at thickness 3–12 nm gave preferential orientation of Zn (100), (002) and (101), though at different intensity.

Zinc Oxide Nanorods Characteristics Prepared by Sol-Gel Immersion Method Immersed at Different Times

This paper focus on zinc oxide (ZnO) nanorods prepared using sol-gel immersion method immersed at different time. Immersion times have been varied 1~24 hr and the characteristics of each sample have been observed. The effects of immersion time on ZnO nanorods thin films have been studied in surface morphology and structural properties using Scanning Electron Microscopy (SEM) and X-ray diffractometer (XRD), respectively.

The Effect of Stabiliser’s Molarity to the Growth of ZnO Nanorods

A wet chemical approach, originating from sol-gel preparation, was adopted with the intention to develop a low-temperature benign method of preparation. ZnO nanorods are successfully grown in an aqueous medium. The precursor, zinc nitrate hexahydrate (Zn(NO3)2.6H2O), is stabilized by hexamethylene tetraamine (HMTA). The effect of changing the molarity of HMTA to the structural orientation of ZnO nanorods is investigated. X-ray diffraction of the synthesized ZnO shows hexagonal zincite structure. The structural features of the nanocrystalline ZnO were studied by SEM. Structural features, surface morphology and differences in lattice orientation are seemingly influenced by varying the Zn2+: HMTA molar ratio. The formation of ZnO nanorods with blunt and sharp tips is found to be significantly affected by this ratio.

Al Doped ZnO Thin Film Based Ultraviolet Photo‐Conductive Sensor Prepared by Sol‐Gel Spin‐Coating Method

Aluminum (Al) doped zinc oxide (ZnO) thin film based ultraviolet (UV) photoconductive sensors were prepared through sol gel spin‐coating method on the glass substrates. The structural and photocurrent properties were investigated for sensor prepared using thin films annealed at 350∼500° C by x‐ray diffractometer (XRD) and current‐voltage (I‐V) measurement system, respectively. The XRD investigation showed that the crystallinity of the thin films increased at higher annealing temperature with preferential growth on (002) orientation. The annealing process at higher temperatures also increased (002) orientation peak of the thin films. The photocurrent properties of Al doped ZnO thin films based ultraviolet photoconductive sensors improved with annealing temperatures as well as UV response characteristic.

Surface morphology study on effect of deposition temperature on nanostructured zinc oxide by chemical vapour deposition method

Abstract Nanocrystalline ZnO was grown on Si and porous Si substrates, by chemical vapour deposition without metal catalyst. Increasing deposition temperature from 400 to 450°C at 0·5 L min–1 Ar flow rate, exhibited an improvement in the spread of ZnO, and smaller clusters of ZnO. At the same temperature range in Ar flow rate of 0·4 L min–1, ZnO nanoflower was formed.

Synthesis and structural properties of zinc oxide flower-like nanostructures by thermal chemical vapour deposition method

Abstract ZnO flower-like nanostructures were grown on Si substrates by thermal chemical vapour deposition method with Au catalyst assisted. The structure obtained on Si substrate composed of hexagonal ZnO nanorods which have hexagonal wurtzite structure with lengths and based diameters in the ranges 200–300 and 100–130 nm respectively. The individual nanorods have a sharp tip in a size less than 100 nm. This sharp tip is suitable for probe and sensor applications. Detailed structural characterisations of the XRD pattern revealed that the ZnO flower-like nanostructures are single crystalline with the wurtzite hexagonal phase and the growth direction along c-axis. The morphologies and the crystal structures of ZnO flower-like nanostructures were characterised by SEM and XRD. Details of the synthesis technique and its properties were explained in this paper.

Synthesis of ZnO nanorods on porous silicon substrate using sol–gel method

Abstract In this study, the authors have synthesised ZnO nanorods on porous silicon (PSi) substrate using sol–gel method. A simple method to synthesise the ZnO nanorods from aqueous solution that contains zinc nitrate hexahydrate [Zn(NO3)2.6H2O] and hexamethylenetetramine (C6H12N4) is presented. The surface morphology and photoluminescence properties of the samples were characterised using scanning electron microscope (SEM) and photoluminescence spectroscope (PL). The SEM images showed that the size of ZnO nanorods increased with the molar ratio of precursor. Photoluminescence measurements showed that ZnO nanorods exhibit a strong ultraviolet (UV) emission of 397 nm and several weak emissions in the blue and green bands.

Diode Characteristics of Zinc Oxide Thin Film at Different Deposition Time for FET Applications

Zinc oxide (ZnO) is a one of the most interesting compound semiconductors that received more attention during last few years due to its unique properties. Due to that, this study has been done to manipulate those properties to be used for FET applications. The ZnO thin film has been deposited using the thermal chemical vapor deposition. This is done in a double furnace, which vapored the ZnO powder at different temperature. The growth of the ZnO thin film has been observed using SEM and the electrical properties has been analyzed by using I-V probe station. This is done to study the diode characteristics of ZnO thin film to be used in FET applications.

Nanostructured Zinc Oxide Thin Film Based Humidity Sensor Prepared by Sol-Gel Immersion Technique

This paper focus on nanostructured Zinc Oxide (ZnO) thin film based humidity sensor prepared using sol-gel method immersion technique at different immersion time. Scanning Electron Microscopy (SEM) investigations reveal nanorods ZnO were deposited on glass substrate with nanorods length increased with immersion time. All fabricated sensors show current intensity increment response when relative humidity is increased. Sensor fabricated at 16 hr immersion time shows the highest sensitivity in this study.

Structural, optical and electrical characteristics of polycrystalline ZnO thin film prepared by sol-gel spin-coating method

The effect of annealing temperatures on the Zinc Oxide (ZnO) thin films properties has been investigated. 1.0 M ZnO solution was prepared by sol-gel method as coating solution for ZnO thin films deposition process. The thin films deposition was conducted by spin-coating technique on the silicon and glass substrates. The scanning electron microscopy (SEM) images reveal the evolution of ZnO surface morphology with annealing temperatures. The crystallinity improvement occurred at higher annealing temperature as shown by x-ray diffraction (XRD) result. The optical properties found to be varied at different annealing temperatures. The current-voltage (I-V) measurement results suggested the improvement of ZnO thin film electrical properties with annealing temperatures.