Mahmood Mohammad Rusop

Synthesis of Carbon Nanotubes by Chemical Vapour Deposition of Camphor Oil over Ferrocene and Aluminum Isopropoxide Catalyst

The aim of this study is to engage a basic understanding of the information carbon nanotubes (CNTs) may yield when this CNTs is deposited on silicon substrate over ferrocene and aluminum isopropoxide catalyst. Several popular methods are used to produce high quality CNT such as chemical vapour deposition, arc discharge and others. Most promising method is, chemical vapour deposition (CVD), used to produce CNTs in this experiment. The carbon source and catalyst were placed at different alumina boat in furnace one (1). The silicon substrate was placed at the deposition furnace and range temperature from 700 oC to 900 oC. The G-band peaks of the CNTs appear at round 1580 cm-1 and D-band peaks appear at 1348 cm-1. Thermal analyses show the percentage of CNTs weight loss 75.12%, 86.39%, 86.54%, 87% and 92.3% respectively. FESEM images was observed to study the formation of the CNTs. The CNTs were successfully synthesized from the chemical vapour deposition method.

Electrical and Structural Properties of ZnO/TiO2 Nanocomposite Thin Films by RF Magnetron Co-Sputtering

In this study, the ZnO/TiO2 nanocomposite thin films were prepared by RF Magnetron co-sputtering ZnO and TiO2 targets at different deposition times from 30-75 minutes. The electrical and structural properties ZnO/TiO2 nanocomposite thin films were characterized by I-V measurement, atomic force microscopy (AFM) and field emission scanning electron microscopy (FE-SEM). The electrical characteristics of nanocomposite films revealed that the conductivity of thin films increases as the thickness increase due to the improvement in surface contact between particles as well as photocatalytic activity. High conductivity at 1.67x10-4 S/cm and lowest resistivity about 5.14x104 Ω/cm were obtained for 75 minutes deposition time. Atomic force microscopy (AFM) showed particle size of ZnO/TiO2 thin films varied from 27nm to 51nm with an increasing in deposition time with granular shapes structures were observed from field emission scanning electron microscopy (FE-SEM).

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.

Surface Morphology and Compositional Analysis of Undoped Amorphous Carbon Thin Films via Bias Assisted Pyrolysis-CVD

Amorphous carbon (a:C) were successfully deposited on the silicon surfaces via bias assisted pyrolysis-CVD in the range between 350oC to 500oC with constant of negative bias -50V in 1 hour deposition. The heated of palm oil at about 150oC was vaporized then used for deposited onto p-type silicon substrates. The deposited thin films were characterized by using field emission scanning electron microscopic (FESEM), energy dispersive analyser x-ray (EDAX). We have found carbon element at about 0.15 keV from EDAX with surface morphology formed a nano-ball like structure at 450oC of palm oil precursor. These results indicated deformation of physical and structural thin films caused by applied negative bias and the temperature.

Solid-State Dye Sensitized Solar Cells: Effect of Hole Transport Material Properties to the Photovoltaic Performance

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.

Deposition of Amorphous Carbon Thin Films via Bias Assisted Pyrolysis-CVD

The as deposited amorphous carbon (a-C) thin films were successfully deposited by using ethanol and palm oil precursors via a novel bias assisted pyrolysis-CVD ranging from 300oC to 550oC with constant of negative bias -40V and -50V in 3h and 1h deposition. The thin films were characterized by atomic force microscopic (AFM), field emission scanning electron microscopic (FESEM), and I-V measurement. The resistivity of as deposited a-C thin films using ethanol precursor at 300oC, 350oC, 400oC and 500oC were 9.57 x106Ω/cm, 9.44 x106Ω/cm, 9.81 x105Ω/cm and 337738.124 Ω/cm respectively and conductivity were 1.00445 x10-7 cm/Ω, 1.0593 x10-7,cm/Ω, 1.01963x10-6 cm/Ω, and 2.67825 x10-6 cm/Ω. For palm oil precursor (400oC-550oC), the resistivity were calculated, 3.83x104Ω/cm, 1.32x104Ω/cm, 3.77x104Ω/cm, and 4.19x105Ω/cm respectively while conductivity were 2.61 x 10- 5 cm/Ω, 7.60 x 10- 5 cm/Ω, 2.65 x 10- 5 cm/Ω, and 2.39 x 10- 6 cm/Ω. The samples showed all the resistivity values were in the range of semiconductor. The results showed that increasing temperature decreased resistivity of thin films for ethanol precursor. The resistivity thin films obtained from palm oil precursor were smaller as compared with ethanol precursor.

Characterization of Copper (I) Iodide (CuI) Thin Film using TMED for Dye-Sensitized Solar Cells

Solid state dye-sensitized solar cells (DSSCs) were first reported in 1991 without employing p-type as hole conductor. The p-type as hole conductor was first introduced in 1995 and CuI is preferred among others p-type semiconductors. However, in 2003 utilizing of CuI based DSSC was found unstable by the excessive iodine strongly decreased the photocurrent of the cell. Later then, the stability of CuI based DSSCs was reported can be improved by added small amount of triethylamine hydrothiocyanate (THT) in the CuI coating solution. Following to that, in this work new chemical is introduce as an option to present situation which can give equally or better effective for fabrication of solid-state DSSCs. The chemical is called tetramethylethylenediamine (TMED), is employed to CuI in sol-gel process and their characterizations have been studied. The CuI coating solution was prepared by dissolved CuI powder with acetonitrile and added in 0.5mL TMED. Using spin coating technique the sol then deposited onto glass and silicon substrate at room temperature. The film were analyzed by their particles conductivity using pH meter, surface morphology using Field Emission Scanning Electron Microscope (FE-SEM) and optical properties using ultraviolet visible spectroscopy (UV-Vis) and photoluminescence (PL) measurement. The results of this sol-gel were compared with other CuI sol-gel which prepared by dissolved CuI powder with acetonitrile only. The optical transmittance within ultra-violet range exhibited that thin film is transparent and it optical band gap have been studied. Further clarification and measurements need to be done in order to prove that the proposed chemical can be used as an option.

ZnO Nanostructures – Nanorods and Flower-Like on Si/Au Substrates by Solution-Immersion Method in Different pH of Precursor

Low-temperature solution immersion growth of low-dimensional ZnO nanostructures on gold-seeded Si substrate has been demonstrated. pH environment of the precursor solution, Zn(NO3)2.6H2O (zinc nitrate hexahydrate) and C6H12N4 (HMTA) was found to have considerable effect to ZnO morphology and photoluminescence. Structural, morphological and photoluminescence (PL) properties of the samples were obtained from XRD, SEM and PL-Raman characterisation. A near neutral (pH = 6.8) and acidic (pH = 5) precursor solution aided a dense near-aligned ZnO nanorods growth with smallest rods diameter of 30 and 20 nm respectively. Whereas alkaline precursor solution (pH = 9) gave rise to flower-like structures of ZnO. Chemical equations for the reactions and the role of H+ and OH- ions role in affecting the XRD diffraction peaks and morphology, are suggested. Room temperature PL emission spectra of ZnO were collected after excitation at 325 nm. UV and visible emission distinctive of ZnO were formed and the rationale for significant shifts of the visible emission was also discussed.

Overview: Zeolite as a valuable crystalline inorganic material

There are continuous interests worldwide in zeolites and we can see it with increasing number of scientific publications of the zeolite. Zeolite is an inorganic material that has very special properties over it. They are characterized by framework structures with uniform pore and channel systems. The term zeolite can be defined as hydrated aluminosilicates belonging to the family of the tecto – silicates, whereas the SiO4 tetrahedral are from three – dimensional super cages. Therefore, the aim of this paper is to study about commercial synthetic zeolite that purchased from Fluka. The results cover by Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD).

Modified fluidised floating catalyst thermal CVD method for preparing carbon nanotubes using Fe/Co/Al

Abstract Carbon nanotubes (CNTs) have been successfully prepared at a low temperature of 650°C by using the fluidised floating catalyst method. Optimum concentration for Fe/Co/Al has been found to be around 0·75% for the best yield. Carbon nanotubes are produced from the evaporation of part of the precursor (camphor oil) which decomposes in situ and aggregates on the metal alloy catalyst particles present in the evaporating boat. Since the metallic alloy was obtained by calcining the respective nitrates, it is expected to have residual entrapped nitrogen which may bond with the depositing CNT. Fourier transmission infrared spectra confirm the presence of nitrogen in the prepared nanotubes which is stipulated to be embedded on the carbon surface in the form of C-N bonding instead of intercalating within the nanotubes.