Ahmad Syakirin Ismail

Thickness-controlled synthesis of vertically aligned c-axis oriented ZnO nanorod arrays: Effect of growth time via novel dual sonication sol–gel process

Zinc-oxide (ZnO) nanorod arrays were successfully prepared by using dual sonication sol–gel process. Field emission scanning electron microscopy revealed that the nanorods exhibited a hexagonal structure with a flat-end facet. The nanorods displayed similar surface morphologies and grew uniformly on the seed layer substrate, with the average diameter slightly increasing to the range of 65 to 80 nm after being immersed for varying growth times. Interestingly, thickness measurements indicated that the thicknesses of the samples increased as the growth time was extended. In addition, the X-ray diffraction spectra indicated that the prepared ZnO nanorods with a hexagonal wurtzite structure grew preferentially along the c-axis. Therefore, we can conclude that the diameter, length, and orientation of the ZnO nanorod arrays along the c-axis are controllable by adjusting the growth time, motivating us to further explore the growth mechanisms of ZnO nanorods.

Structural and optical properties of N-doped ZnO nanorod arrays prepared using sol-gel immersion method

Nitrogen (N)-doped zinc oxide (ZnO) nanorod arrays were synthesized on aluminium (Al)-doped ZnO seed layer catalyst using sol-gel immersion method. The XRD analysis showed that the increment in crystallite sizes and lattice parameters while the strain/stress of the films reduced when the concentration increased. The FESEM image revealed that the nanorods exhibit hexagonal shape. The average diameters of nanorods have increased from 150 nm (undoped) to 230 nm (3 at.%). The N-doped ZnO nanorod arrays also displayed good transmittance properties at visible region.

Low temperature growth of rutile titanium dioxide nanorod arrays using a novel facile method for UV photosensor application

Titanium dioxide (TiO2) nanorod arrays (TNAs) were deposited on fluorine-doped tin oxide (FTO) coated glass substrate via a novel and facile method at the lowest deposition temperature of 110 °C for 3 hours, and characterized via fiel-demission scanning electron microscopy (FESEM), and ultraviolet-visible (UV-Vis) spectrophotometer. Self-powered UV photosensor was assembled according to photo-electrochemical cells (PEC) structure using the deposited TNAs as photoanodes. The fabricated UV photosensor was then studied for its electrical property. The fabricated UV photosensor exhibits fast response with high sensitivity under UV irradiation. A distinct ON/OFF ratio of the fabricated PEC structure also exhibits photo-sensing property as photo-anode, and can be implemented for the application of UV photosensor. The large contact area of the TNAs/electrolyte interface leads to the generation of photocurrent and exhibits improvement in conductivity.

Fabrication of Titanium dioxide nanorod arrays-based UV photosensor from low-concentration of Titanium (IV) butoxide with hydrochloric acid

A novel and facile method at lowest concentration of titanium (IV) butoxide with hydrochloric acid at 150 °C temperature for 3 hours was implemented for the growth of Titanium dioxide (TiO2) nanorod arrays (TNAs) on fluorine-doped tin oxide (FTO) glass substrate. The deposited TNAs were characterized by field-emission scanning electron microscopy (FESEM), and ultraviolet-visible (UV-Vis) spectrophotometer. Self-powered UV photosensor was designed based on photo-electrochemical cells (PEC) using the deposited TNAs as photo anodes. The performance of the fabricated UV photosensor was studied based on its photo-generated current and response under UV irradiation (365 nm). The fabricated UV photosensor displays fast response and recovery time under an ON/OFF state of UV irradiation with comparatively high sensitivity. The photosensor fabricated at the lowest 0.05 M of titanium (IV) butoxide with hydrochloric acid of TNAs exhibits photo-sensing property as photo-anodes, and can be implemented for the application of UV photosensor. Large surface area of TNAs leads to the high generation of photocurrent and shows increment in conductivity under UV irradiation.

Aluminum- and Iron-Doped Zinc Oxide Nanorod Arrays for Humidity Sensor Applications

Metal-doped zinc oxide (ZnO) nanorod arrays have attracted much attention due to improvement in their electrical, structural, and optical properties upon doping. In this chapter, we discuss the effects of aluminum (Al)and iron (Fe)-doping on ZnO nanorod arrays properties particularly for humidity sensor applications. Compared to Fe, Al shows more promising characteristics as doping element for ZnO nanorod arrays. The Al-doped ZnO nanorod arrays showed dense arrays, small nanorods diameter, and high porous surface. The I-V characteristics showed that Al-doped sample possesses higher conductivity. From the humidity sensing performance of the samples, Al-doped ZnO nanorod arrays possess the superior sensitivity, more than two times higher than that of the undoped ZnO nanorod arrays sample, demonstrating great potential of Al-doped ZnO nanorod arrays in humidity sensor applications.

Effect of deposition speed on properties of zinc oxide nanoparticle decorated zinc oxide nanorod arrays

The study investigated the impact of deposition speed on goods of zinc oxide (ZnO) nanoparticle decorated zinc oxide nanorod arrays. The ZnO nanoparticle coatings were deposited at various speeds ranging from 1000 to 3000 rpm. The results showed that the density of ZnO nanoparticle coated on ZnO nanorod arrays was decreased when the deposition speed increased from 1000 to 3000 rpm. This study is a primary phase regarding the optimized growth of three-dimensional branched zinc oxide nanorod arrays based humidity sensor.

ZnO/SnO2 nanoflower based ZnO template synthesized by thermal chemical vapor deposition

The ZnO/SnO2 nanoflower like structures was grown on a glass substrate deposited with seed layer using thermal chemical vapor deposition (CVD) with combining two source materials. The ZnO/SnO2 nanoflower like structures had diameter in the range 70 to 100nm. The atomic percentage of ZnO nanoparticle , SnO2 nanorods and ZnO/SnO2 nanoflower was taken using EDS. Based on the FESEM observations, the growth mechanism is applied to describe the growth for the synthesized nanostructures.

Preparation of nickel oxide thin films at different annealing temperature by sol-gel spin coating method

Preparation of NiO thin films at different annealing temperature by sol-gel method was conducted to synthesize the quality of the surface thin films. The effects of annealing temperature on the surface topology were systematically investigated. Our studies confirmed that the surface roughness of the thin films was increased whenever annealing temperature was increase. NiO thin films morphology structure analysis was confirmed by field emission scanning electron microscope. Surface roughness of the thin films was investigated by atomic force microscopy.

Percentage of different aluminum doping influence the morphological and optical properties of ZnO nanostructured growth for sensor application

In this work, Zinc Oxide (ZnO) with different aluminum (Al) doping percentage was synthesis by sol gel immersion method. Al doped ZnO at various doping percentage from 1, 2, 3, 4 and 5. It was found that with different Al percentage influence the morphological and optical properties of ZnO growth. Field Emission Scanning Electron Microscope (FESEM) image showed the use of different Al doping causes the difference in geometry and size of ZnO nanorods growth. Based on UV-Vis spectroscopy, the transmittance at 1% Al doping has the highest spectrum.

Humidity Sensor - A Review of Nanostructured Zinc Oxide (ZnO) - Based Humidity Sensor

We have reviewed humidity sensors based on the Zinc oxide (ZnO) humidity sensor. There are only a few papers reviewing on the ZnO humidity sensor. The characteristics, structures, advantages, and fabrication methods of ZnO have been studied to understand the suitability of the ZnO to be applied at different kind of condition such as for extreme environment, low level humidity detection, and very high humidity level circumstances. The electrical and physical properties of ZnO humidity sensors such as sensitivity, response time, stability, uniformity, and crystallinity have also been discussed in this review. ZnO nanostructures have been widely used for humidity sensors because of its’ good stability, high sensitivity for humidity-sensing, low cost, and has a wide band gap. Sol-gel preparation method is commonly used to for ZnO humidity sensor fabrication since it can produce a film with high uniformity, simple process and low cost. Keywords: Humidity Sensor, Metal Oxide, Semiconducting Type, Ceramic Type, Humidity-Sensing, Band Gap, Sol-Gel Preparation Method.