F.S. Husairi

Synthesis of ZnO Thin Film on Porous Silicon by Spin Coating in Various Low Molarities Precursor

Zinc acetate dehydrate as starting material along with diethanolamine as stabilizer, and isopropyl as a solvent were used to synthesis ZnO thin films in different low molarities. Sol-gel spin coating method was used in depositing ZnO on porous silicon substrate surface. In other to prepare substrate, p-type silicon wafer was etched by dilute hydrofluoric acid to modify the surface becomes porous. Field Emission Scanning Electron Microscopy (FESEM) was employed to study the surface morphology. It is found that ZnO thin films were successfully deposited on the substrates which are composed of ZnO nanoparticles with size ~16 nm to ~22nm. Atomic Force Microscopy (AFM) was used to investigate the surface roughness of thin film. The result shows that the surface roughness is increase as the increases of molarities. Photoluminescence (PL) spectra were done in range of 350 nm to 800 nm. The result shows peaks belonging to ZnO, ZnO defects, and porous silicon respectively are appeared.

I-V and Surface Topography Study of Nanostructure Porous Silicon Layer Prepared by Electrochemical Etching

This article reports on the electrical properties of porous silicon nanostructures (PSiNs) in term of its surface topography. In this study, the PsiNs samples were prepared by using different current density during the electrochemical etching of p-type silicon wafer. PSiNs has been investigated its electrical properties and resistances for different surface topography of PSiNs via current-voltage (I-V) measurement system (Keithley 2400) while its physical structural properties was investigated by using atomic force microscopy (AFM-XE100).

Micro-Raman, Optical and Impedance Characteristics of CNT-Substituted Acrylate/CNT Nanocomposite Thin Film

Carbon nanotube (CNT) has been synthesized using camphor oil as a starting material via two-stage catalytic chemical vapor deposition. The as-synthesized CNT was then incorporated into acrylate matrix by suspension polymerization method, using various loading of CNT (as a filler) varied from 0.2 to 1.0 g with 0.2 g weight interval in the nanocomposite thin film. The acrylate/CNT nanocomposite thin film was characterized using micro-Raman, ultraviolet-visible and impedance spectrometer. As confirmed, the various loading of CNT had a significant impact on structural, optical and impedance characteristics. The paper contributes the recent achievements in material progress of CNT/polymer nanocomposite.

Optical Properties of Nano-Porous Structure ZnO Prepared by Catalytic-Immersion Method

This paper presents an efficient method to prepare ZnO nano-porous structure via immersion of Si substrate with catalyst assistance (gold) in the mixture of zinc nitrate hexahydrate (Zn(NO3)2.6H2O) and urea (CH4N2O). Photoluminescence (PL) spectra of nano-porous ZnO revealed it had strong UV emission with low oxygen defect. Optical properties are found to be significantly affected by varying the Zn2+: urea ratio but from surface morphology observation, the porous structure was stabile and seemingly unchanged.

Synthesis and temperature dependence of I-V characteristic of spin-coated nanostructured ZnO on P-type silicon

P-type silicon was used as a substrate of deposition of nanostructured ZnO by sol-gel spin coating technique, while zinc acetate, diethanolamine, and isopropyl were used as starting material, stabilizer and solvent respectively. Surface morphology was studied by Field Emission Scanning Electron Microscopy (FESEM). It was found that nanostructured ZnO was distributed uniformly over the P-type Silicon substrate. This was supported by atomic force microscopy (AFM) image which shows the all the surfaces are covered by nanoparticle of ZnO. X-ray diffraction (XRD) was employed to analyse the structural and crystalline of nanostructured ZnO. Three peak (100), (002), and (101) correspond to nanostructed ZnO are appear. Temperature dependence I-V characteristic was investigated in range of 25 K to 300 K by using Close Cycle Cryostat and using Helium as cooler agent. It is found that the resistance were decrease toward the higher temperature. The result shows that resistivity gradually decreased due to increases of temperature.

Annealing Effect on the Surface Morphology and Photoluminescence Properties of ZnO Hexagonal Rods by Immersion Method

ZnO hexagonal rod structure were prepared by immersion method deposited onto Si (Si/ZnO) and gold-seeded Si substrate (ZnO/Au/Si). The annealing temperatures were varied from 400, 500 and 600 °C. The effect of annealing temperature on the surface morphology and photoluminescence characteristics was investigated. The samples were characterized by Field Emission Scanning Electron Microscope (FESEM) to study their morphology and structural properties while the optical properties were characterized at room temperature using Photoluminescence Spectroscopy. The shape of ZnO showed growth of rods with hexagonal shape. As the annealing temperature increased, the morphology study indicates that diameter size of ZnO decreased while the crystallinity increases. The structures has high surface area, is a potential metal oxide nanostructures to be develop for optoelectronic devices and chemical sensors.

Preparation of LaPO4 with Different Morphologies and Fluorescence Properties by Sol-Gel Spin-Coating Method

Lanthanum Phosphate (LaPO4) nanostructures thin films have been successfully synthesized by sol-gel spin coating technique from lanthanum nitrate and ammonium phosphate in ammonia solution. The procedure starting with formation of homogenous and transparent solution followed with annealing to form the LaPO4 nanostructures thin films. The films were annealed at different temperature to study its effect to the surface morphology and optical properties of the films. The phosphate particles are having near-spherical to rod-like nanostructures with an average size about 15 nm. The morphology is retained even the annealing temperature is increased. Furthermore, photoluminescence (PL) characterization of LaPO4 also was reported. The effect of annealing temperature was discussing detail. The intensity as well as optical brightness is highly dependent on anneal temperature. Fourier transform infra red spectra of films obtained are similar to the previous synthesis of phosphate. Thus, confirmed the formation of LaPO4 on the glass substrate.

ZnO nanostructures on different silicon–based substrate via simple sol–gel immersion method

In this work, ZnO nanostructures using zinc nitrate as starting material grown on different silicon–based substrate were studied. Porous silicon was prepared by electrochemical etching to modify the silicon surface. Field emission scanning electron microscopy (FESEM) displays different distribution and nanostructures of ZnO on different substrate. The seeded substrates show the better site for the growth of ZnO nanostructure due to presence of nucleation site. Crystalline of ZnO nanostructure were investigated by X–ray diffraction (XRD) grating. It is found that the hexagonal wurtzite of ZnO nanostructures were produced for all samples. The peaks (100), (002) and (101) are dominating for all samples prove that hexagonal structures of ZnO were formed. Photoluminescence spectra were employed in order to study the optical properties. The peak centred at 395-398 nm corresponds to free–exciton recombination ZnO nanostructures are found in silicon and porous silicon, respectively.

Electrical properties of carbon nanotubes synthesis by double furnace thermal-CVD technique at different temperatures on porous silicon template

Multiwalled Carbon Nanotubes (MWCNs) were synthesized using double-furnace thermal chemical vapor deposition technique at 700 – 900 °C on porous silicon nanostructure (PSiNs). Palm oil used as a carbon natural source, ferrocene as a catalyst and nitrogen gas as a carrier gas. The precursor were vaporized at 475 °C carried by nitrogen gas which flow at constant rate 150 sccm/min. Carbon nanotubes characterized by using Raman Spectroscopy and field emission scanning electron microscopy (FESEM) to check its structure and crystallites before tested with I-V probe. Au contact used as a metal contact deposited on CNTs layer. Carbon nanotubes (CNTs) with uniform diameter were found grown on porous silicon for each temperature used. Based on micro-Raman spectroscopy result, the peak of carbon nanotubes (around 1 300 to 1 600 nm) was detected. The I-V characteristic of CNTs deposited had different profile when deposited at different temperature.

Seeded Porous Silicon Preparation as a Substrate in the Growth of ZnO Nanostructures

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.