Advanced Materials Research Vol. 667

Abstract: Nano-magnesium oxide, MgO film was successfully prepared at various annealing temperatures (400, 450, 500 and 550°C) by using sol-gel method. The behaviour of the MgO as a dielectric layer was investigated in term of its electrical behaviour, relative permittivity and structural properties. The leakage current density obtained was below 10-9 A/cm2 in which is suitable to be used as dielectric layer. Resistivity and relative permittivity values were found to fluctuate with applied annealing temperatures and it was revealed that these changes were related to the surface morphology of the prepared nano-MgO films. Interesting surface morphology was observed for film annealed at 500°C, in which the film formed an island structure, composed of nano particle MgO in range of 45 to 74 nm.

Abstract: This review summarizes the current state of lead zirconium titanate (PZT) that used for energy storage based organic capacitor. The particular focus is on dielectric material PZT properties for achieving high-k dielectric constant (900-1300) concerning for DC power application. PZT is well known of its perovskite structure that related to excellent ferroelectric properties considered to have high remnant polarization and low coercive field. We review the recent literature that focused on the annealing process that affects dielectric constant and its structural property derived by radio frequency (RF) magnetron sputter.

Abstract: The improvement of solid-state dye sensitized solar cells requires identification and understanding of hole transport material properties at various deposition process that limit the energy conversion efficiency. A well-studied of this hole collectors properties, a high efficiency ss-DSSC is highly achievable. In this research work, the copper (I) iodide (CuI) had been deposited by spin coating and mist-atomization technique. The thin films characteristics of surface morphology and electrical properties and its effect to the photovoltaic performance were investigated. The thin films morphology examined by FESEM shows smaller CuI crystal size deposited by spin coating (S1) of ~30nm. Even though, smaller particle size of hole conductor is desirable in order to achieve high pore penetration, the thin film thickness and the electrical resistivity are also essential. The CuI thin films deposited by mist-atomization (M1) shows a low resistivity of 1.77 x 10-1 Ωcm which will greatly affect the device performance. The photovoltaic performance of ss-DSSC at different method CuI deposition shows the highest efficiency of 1.05% for sample (M1) while the ss-DSSC fabricated with S1 sample shows the lowest conversion efficiency of 0.02%. The appropriate crystals size of CuI, film thickness and the electrical resistivity greatly contributed to the high filling fraction of the porous TiO2 layer and hence the cells performance.

Abstract: Nanostructured porous silicon templates (NPSiT) were prepared by photo-electrochemical anodization of p-type crystalline silicon in HF electrolyte at different etching time. Two set anodisation parameter were observed, anodisation time nd current density applied. For set one, five samples were prepared with etching time varied from 10 to 50 minutes at 20 mA/cm2 of current density. For set two, five samples were prepared with current density varied from 5 to 40 mA/cm2 for 30 minutes. The effects of these anodisation parameter on NPSiT were observed based on nanocrystallite size. These studied was demonstrated by Raman spectroscopy. It was found that NPSiT sample with large pore diameter, which is smaller nanocrystallites size of Si between pore.

Abstract: This paper presents a review on synthesis, structure, and growth mechanisms of one-dimensional nanostructures of ZnO. Solution-based method is a potential deposition technique for large-scale production as its advantages; the low cost, the simplicity of experimental set-up, and the low operating temperature. Mist-atomiser technique is one of the solution-based methods in synthesizing optimized ZnO nanostructures. Doping will lead for better properties of ZnO, which result to wide application area. Nanostructured ZnO is important in promising areas of application which devices utilizing nanostructures such as gas sensors and solar cells, since it is fairly easy to fabricate such forms of ZnO nanostructures, which have good charge carrier transport properties and high crystalline quality.

Abstract: Zinc Oxide (ZnO) thin films were deposited on thermally oxidized SiO2 by varying the oxygen flow rate. The deposition process were done using radio frequency (RF) magnetron sputtering at various oxygen flow rate ranging from 0 to 40 sccm. The surface morphology and crystallinity were analyzed by field emission scanning electron microscopy (FESEM) and X-Ray Diffractometer (XRD) respectively. The average thickness and deposition rate decreases with an increase of oxygen content. The grain size was measured by FESEM and it was found that it is also decreasing with the increased of oxygen flow rate. The films grown with 10 sccm oxygen shows the highest (002) peak however it is expected that the sample deposited with 40 sccm oxygen exhibit the highest sensitivity toward NH3 gas due to the highest surface to volume ratio.

Abstract: ZnO heterostructures have been successfully synthesized using thermal chemical vapor deposition method. Zinc powder and oxygen were used as the starting materials, while argon gas was supplied as the carrier gas. Different types of nanostructures were deposited on layer-by-layer ZnO seeded catalyst; which its structures depended on the position of the substrates during the deposition process. Substrates at position C which is located 3 cm from the source shows uniformly distributed ZnO nanorods. XRD pattern also shows that sample C shows (0 0 2) diffraction peak. PL spectra indicates that the ZnO have two peaks, which is UV peak centered at 380 nm and visible peak centered at about 550 nm.

Abstract: Carbon nanotubes The discovery of ‘fullerenes’ added a new dimension to the knowledge of carbon science1; and the discovery of ‘carbon nanotubes’ (CNTs, elongated fullerene) added a new dimension to knowledge of technology2. Today, ‘nanotechnology’ is a hot topic attracting scientist, industrialists, journalist, governments, and even the general public. Nanotechnology is the creation of functional materials, devices and systems through control of matter on the nanometer scale and the exploitation of novel phenomena and properties of matter (physical, chemical, biological, electrical, etc.) at that length scale. CNTs are supposed to be the key component of nanotechnology. Almost every week a new potential application of CNTs is identified, stimulating scientists to peep into this tiny tube with ever increasing curiosity.

Abstract: We illustrated the optimization of the growth of multi-wall carbon nanotubes (MWCNTs) using thermal chemical vapor deposition (CVD). Palm-based dihydrostearic acid (DHSA) which was never been reported as a precursor, was used as the precursor over five different trimetallic catalysts for the growth of MWCNTs. These trimetallic catalysts were prepared by sol-gel method and used to study on the effect of the production of the MWCNTs from palm DHSA. With different catalyst, the characteristics of MWCNTs changes such as diameter and crystallinity which was confirmed by SEM and Raman spectroscopy studies. The trimetallic catalysts give high yield and offer good graphitization of MWCNTs produced from palm DHSA.

Abstract: Carbon nanotubes (CNTs) were produced on silicon (Si) substrate prepared by Thermal-CVD method using C55H96O6 (Palm Oil) as a starting material. Catalyst has been prepared by dissolving Nickel (II) nitrate, Ni (NO3) 2.6H2O and ethyl alcohol, C2H5OH. The CNTs was deposited on nickel coated silicon where the nickel acts as catalyst .Various parameters such as amount of catalyst, amount of palm oil, deposition time, deposition temperature, flow rate of gas and carrier gas have been studied. By using Thermal-CVD, samples were penetrated using NH3 (argon) gas at a temperature 700-900oC for catalyst and 450oC for Palm Oil. Surface morphology and uniformity of CNTs were characterized using FESEM at different deposition temperature. Chemical functional groups of CNTs were characterized using FTIR. The surface morphology and uniformity of CNTs are dependents on parameters used.