M. J. Salifairus

The effect of synthesis time on graphene growth from palm oil as green carbon precursor

Graphene is the new material that arises after carbon nanotubes (CNTs) era and has extraordinary optical, electronic and mechanical properties compared to CNTs. The 2D graphene is the sp2 carbon allotropes compared to other dimensionality. It also can be in three forms that are zero-dimensional, one-dimensional or three-dimensional. The different dimensionality also called fullerenes, nanotubes and graphite. Therefore, the graphene is known as centre potential materials in expanding research area than others ever. The 2cm × 2cm silicon wafer was seeded with nickel (Ni) at different thickness by using sputter coater. The palm oil, carbon source, was placed in the precursor furnace and the silicon was placed in the second furnace (deposition furnace). The palm oil will mix with Nitrogen gas was used as carrier gas in the CVD under certain temperature and pressure to undergo pyrolysis proses. The deposition temperature was set at 1000 °C. The deposition time varied from 3 minutes, 5 minutes and 7 minutes. Th...

The synthesis of graphene at different deposition time from palm oil via thermal chemical vapor deposition

The basic building of graphitic materials is graphene that can range from zero-dimensional to three-dimensional. Graphene is a single atomic layer of sp2 bonded carbon atoms. It becomes most potential new materials to replace silicon due to its fascinating properties. In this study, the graphene growth was observed at different deposition time. The 1cm x 1cm polycrystalline nickel substrate was cleaned by etching process. The palm oil, carbon source, was placed in the precursor furnace and the nickel substrate was placed in the second furnace (deposition furnace). The palm oil will mix with Argon and Hydrogen gas was used as carrier gas in the CVD under certain temperature and pressure to undergo pyrolysis process. The deposition temperature was set at 900 °C and the deposition time was varied from 5 - 60 minutes. The graphene was growth at ambient pressure in the CVD system. Raman spectrometer and atomic force microscopy revealed the structural properties and surface topography of the grapheme on the nickel substrate. The D, G and 2D band appear approximately at 1378 cm−1, 1580 cm−1 and 2696 cm−1. It can be concluded that the graphene has successfully synthesized at different deposition time.

The synthesis of graphene from palm oil at different annealing time of nickel substrate via thermal chemical vapor deposition

Graphene has shown a plethora potential of applications with its extraordinary electronic and mechanical properties. It is a 2D carbon allotrope which carbon atoms are arrayed in a hexagonal honeycomb lattice. Graphene was synthesized on the polycrystalline nickel substrate with a dimension of 0.10 mm × 10 mm × 10 mm via thermal chemical vapor deposition (TCVD). The carbon precursor was obtained from a commercial palm oil as a natural carbon source. The D, G, and 2D bands described the vibration of graphitic layer and overtone of the D band at 1357, 1595 and 2703 cm−1 respectively. The lowest G band full width at half maximum (FWHM) was 42.95 cm−1 at 15 minutes annealing time. Raman spectroscopy, UV-vis spectrophotometry, atomic force microscopy, XRD and field emission scanning microscopy characterized the synthesized graphene. Multi-layer graphene was successfully synthesized from the palm oil via TCVD.Graphene has shown a plethora potential of applications with its extraordinary electronic and mechanical properties. It is a 2D carbon allotrope which carbon atoms are arrayed in a hexagonal honeycomb lattice. Graphene was synthesized on the polycrystalline nickel substrate with a dimension of 0.10 mm × 10 mm × 10 mm via thermal chemical vapor deposition (TCVD). The carbon precursor was obtained from a commercial palm oil as a natural carbon source. The D, G, and 2D bands described the vibration of graphitic layer and overtone of the D band at 1357, 1595 and 2703 cm−1 respectively. The lowest G band full width at half maximum (FWHM) was 42.95 cm−1 at 15 minutes annealing time. Raman spectroscopy, UV-vis spectrophotometry, atomic force microscopy, XRD and field emission scanning microscopy characterized the synthesized graphene. Multi-layer graphene was successfully synthesized from the palm oil via TCVD.

Surface morphology and molecular bonding of CaCO3 nanocrystallites by gas diffusion method

Calcium carbonate with the chemical formula of (CaCO3) is the most abundant element in the world. Its usage on certain applications is largely affected by its properties. The best means to control its properties is through controlled preparation of CaCO3. This study uses diffusion method between the precursors Calcium Chloride and Ammonium Carbonate. Instead of using water, ethanol was used to prepare the salt. Reaction was done in room temperature (RT) for 6h-24h. Smallest average crystallite size measured by FESEM micrograph is 500nm produced by synthesis of CaCO3 reacted for 168 hours. From energy-dispersive X-ray spectrum also indicated the smallest particle size is by CaCO3 reacted for 168 hours. Changes was seen for element Ca at 3.7keV.Calcium carbonate with the chemical formula of (CaCO3) is the most abundant element in the world. Its usage on certain applications is largely affected by its properties. The best means to control its properties is through controlled preparation of CaCO3. This study uses diffusion method between the precursors Calcium Chloride and Ammonium Carbonate. Instead of using water, ethanol was used to prepare the salt. Reaction was done in room temperature (RT) for 6h-24h. Smallest average crystallite size measured by FESEM micrograph is 500nm produced by synthesis of CaCO3 reacted for 168 hours. From energy-dispersive X-ray spectrum also indicated the smallest particle size is by CaCO3 reacted for 168 hours. Changes was seen for element Ca at 3.7keV.

One step precipitation of CaCO 3 nanoparticles assisted by drying and hydrothermal method

Calcium Carbonate (CaCO3) is one of the most abundant natural resource exists. Precipitation is the most famous bottom up approach to synthesize CaCO3. This work explained preparation of (CaCO3) by unfiltered precipitation method and further dried by different methods. Different drying methods were executed post-precipitation step; normal drying and hydrothermal. Precipitated CaCO3 dried by normal drying managed to eliminate all Nitrogen (N) whereas drying by hydrothermal method still has traces of N left. The polymorphs of the synthesized CaCO3 are mostly calcite with traces of vaterite present. Normal drying method produced smaller CaCO3 crystallite size of 64.9nm compared to hydrothermal drying method synthesized CaCO3 with crystallite size 93.2nm. Annealing temperature is inversely proportional to the crystallite size of the treated CaCO3. Smallest crystallite size of synthesized CaCO3 is 25.5nm dried by normal drying method at 500°C. To the best of our knowledge, this is the first report of unfiltered precipitation and also the first to report on polymorph and crystallite size of CaCO3 synthesized by different drying methods.

Surface topography of synthesized graphene from green carbon source using thermal chemical vapor deposition

The graphite oxide has been a common carbon source to synthesis graphene layers [1-3]. In this study, palm oil has been proposed as one of the green carbon source available and environment friendly. The double furnace CVD method was used to synthesis graphene layers [4]. The nickel sheet was used as a substrate and palm oil act as carbon feedstock to supply carbon atom. The substrate and carbon source were placed in two different furnaces. The carbon source furnace and the substrate furnace were heated to 300°C and range from 850°C to 1100°C consecutively. The argon was used as carrier gas to carry the carbon atom towards the substrate. The both furnaces were switch off after several time synthesis times for cooling process. The Atomic Force Microscopy, UV-VIS Spectroscopy, FTIR spectroscopy and Raman spectroscopy was used to characterize the as-synthesized graphene.

Effect of temperature to the structure of silicon nanowires growth by metal-assisted chemical etching

A simple and low cost method to produce well aligned silicon nanowires at large areas using metal assisted chemical etching at various temperature were presented. The high aspect ratio structure of silicon nanowires growth by anisotropic wet etching method was observed. Prior to the etching, the formation of silicon nanowires was by metal assisted chemical etching (MACE) in solution containing hydrofluoric acid and hydrogen peroxide in Teflon vessel. The silver nanoparticle was deposited on substrate by immersion in hydrofluoric acid and silver nitrate solution for sixty second. The silicon nanowires were grown in different temperature which are room temperature, 30°C, 40°C, 65°C and 80°C.The effect of increasing temperature to the formation of silicon nanowires was studied. The morphological properties of silicon nanowires were investigated using field emission scanning electron microscopy (FESEM) and Energy Dispersive X-Ray Spectroscopy (EDX). The optical properties of silicon nanowires were investigated using Uv-Vis spectroscopy.