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A novel approach, namely photocatalytic esterification and addition reaction of unsaturated fatty acids using CuO/TiO2 catalyst has been investigated in kemiri sunan oil. The objectives of this study are to reduce the free fatty acid (FFA) content by using catalyst CuO/TiO2, characterization of the catalyst and the operation condition of reaction. The CuO/TiO2 catalyst was synthesized by the impregnation of TiO2 P25 powder with copper nitrate solution as a precursor and followed by calcination. The field emission scanning electron microscopy (FESEM), Energy Dispersive X-ray (EDX), X-ray Diffraction (XRD), and Transmission electron microscopes (TEM) result showed that copper oxide was highly dispersed on the TiO2 surface. The X-ray Photoelectron Spectroscopy (XPS) result showed that Cu is in the state of CuO (Cu2+), while Ti is in Ti4+ ( TiO2). The bandgap energy of CuO/TiO2 was smaller than TiO2 P25. It was found that the reactions conducted in the presence of CuO/TiO2 in a photoreactor under UV irradiation can perform esterification and addition reaction of the FFA, simultaneously. The optimum reduction of the FFA was under condition of 4% loading CuO/TiO2, 4 hours reaction time, 30:1 (mole/mole) methanol to oil ratio, 5% (w/w) catalyst amount. The conversion of FFA was at around 59%. The Gas Chromatography—Mass Spectrometry (GC-MS) results showed that the addition reaction of -eleostearic acid simultaneously occured at 100% conversion. Although the photocatalyst selectivity in FFA reduction was relatively low, but double bond reduction of -eleostearic acid (C18:3) was very high. The reduction of multiple double bond is considered as positive poin to improve the oxidative stability of the product. The simultaneous esterification and addition reactions mechanism has been proposed. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Extraction of ripened noni juice has been carried out using ethanol and water. The purpose of this study was to determine the total phenolic, total flavonoids, scopoletin, content and antioxidant activity of the ripened noni juice extract. The activity test was carried out on the ripened noni juice extract without and with the addition of ethanol and water solvent. The phytochemical assays of ethanol extract of the ripened noni juice showed that thetotal phenolic content was 3,94 mg gallic acid equivalent/g extract, the total flavonoids was 0,59 mg quercetin equivalent /g extract, the IC50 antioxidant activity was 24,92 mg/L, scopoletin content was 2,45 mg/gram.Keywords : Antioxidant, flavonoids, phenolic, ripened noni juice, scopoletin

Volcanic ash contains essential elements to the soil fertility of agricultural land which is important to be investigated. The aim of this study was to determine the distribution pattern of volcanic ash essential elements as a result of volcanic eruption disaster using Surfer software. To input, the Surfer software, soil samples of volcanic ash at 10 sampling locations in Sleman at a radius of 14 to 26 km towards the south from a peak of Merapi were collected. Data of wind direction, humidity and ground level at the time of sampling were also collected. The concentrations of the essential element in samples were measured using NAA (neutron activation analysis). The pH of volcanic ash samples in each sampling locations was also measured. The results showed that volcanic ash for all sampling locations contained, Al, Fe, Na, K, and Si as major elements and Zn, Co, and Se as trace elements. The concentration distribution pattern of the Zn, Si, Co and Fe elements tends to decrease towards the peak of Merapi, on the other hand, the Na, and K elements showed that their distribution concentration tends to decrease away from the peak of Merapi. The wind’s speed affects the distribution range of an element contained in volcanic ash samples. The pH of volcanic ash samples seemingly only affect the concentration of Zn elements in the distribution pattern of elements.

This study aims to utilize abundant glycerol because the production is more than the consumption. The use of glycerol is carried out through a carbonylation reaction between glycerol and urea to obtain glycerol carbonate. In the carbonylation reaction, variations in the use of CaO catalysts were carried out at 130°C and 160°C and the use of ZnO catalysts at 160°C. The results of product testing using GC-MS showed that the desired glycerol carbonate was not detected, but 1,3-dioxol-2-one was detected as the reaction result in the largest amount. The carbonylation reaction using catalyst CaO 1 mol% with a temperature of 160°C and constant stirring for 3 hours resulted in a conversion of 92.86% and a 1.3-dioxol-2-one yield of 64.80%. The carbonylation reaction using ZnO 1 catalyst mol% at 160°C and constant stirring for 3 hours can produce a conversion of 94.88% and a 1,3-dioxol-2-one yield of 30.06%.

Methyl bromide is an excellent fumigant but has been banned because it has high potential for depleting the ozone layer which leads to many environmental and human health hazard issues. In this connection, effectiveness of carbon dioxide (CO2, 99.9%) was studied as an alternative to methyl bromide under various exposure timings, 25 ± 1 °C, against different developmental stages of the almond moth, Cadra cautella, and red flour beetle, Tribolium castaneum. In case of C. cautella, the LT99 against adult, pupa, and larval stages was achieved after 37.5, 78.1, and 99.9 h of CO2 application, respectively. While for T. castaneum, the LT99 values were obtained after exposure timings of 29.3, 153.9, and 78.4 h against adult, pupa, and larval stages, respectively. Adults were very susceptible; in contrast, pupae and larvae were more tolerant. The susceptibility order was observed as follows: T. castaneum adult > C. cautella adult > C. cautella pupae > T. castaneum larvae > C. cautella larvae > T. castaneum pupae. This study could be useful in developing the management strategies to prevent stored dates from C. cautella and T. castaneum infestation.

Gasoline combustion in an engine always produce carbon particle which then agglomerate, precipitate, and degrade the engine performance. In this research PIB amine, a surfactant having PIB as the hydrocarbon nonpolar tail and TEPA as polar head, is prepared and tested as deposit controlling agent (DCA) f or gasoline. This reaction product is a viscous liquid with density 0,8566 g/ml and kinematic viscosity @40°C of 75,16 cSt, and on its FTIR spectrum shows peak at 3200-3500 cm−1 (amine group). Its anti-deposit performance has been tested using single cylinder gasoline engine, at concentration 300 ppm PIB amine can significantly reduce deposit, comparable to that of the commercial PIBA. The 300 ppm PIB Amine gasoline is also pass gum test, with unwash gum value

ETBE or Ethyl Tertiary Butyl Ether is an oxygenate additive that can be the solution for the air pollution's problems due to carbon emissions, especially CO gas. However, in the process of producing ETBE there is still obstacles in the form of low conversion results. In this study, additive synthesis containing ETBE was carried by using fixed-bed reactor for 1 hour with ethanol and isobutylene reactants and H-ZSM 11 catalyst aid which had a SiO2 / AlO3 50 ratio and a pore volume of 0.2 cm3 / g. The experiment was carried out with temperature variations of 750C - 950C. Based on the GC-MS test, 71% additive and 13% yield were obtained at 900C reactor temperature. This additive raises the octane number from 88.7 to 88.9 with an additive of 1000 ppm at premium base. Addition of 1000 ppm additives in gasoline reduces deposit formation from 0.0186% to 0.0035% and formation of CO emissions from 0.723% to 0.245%. The data resulted in a decrease in deposit formation by 0.0151% and a decrease in CO emissions of 0.478%.

Fuel is still a crucial commodity in this world. Fuel can be utilized in various economic activities, such as on vehicle. The utilization of fuel in vehicle often produce deposit and pollution that came from imperfect combustion. One alternate solution to improve fuel combustion efficiency and reduce pollution is by formulating fuel additive that can control deposit in vehicle combustion chamber. Deposit Control Additive (DCA) consists of polar head and hydrocarbon tail as a non-polar end has a similarity of structure with surfactant. One of the results of amination reaction which is Polyisobutylene (PIB) – amine has proven its ability as DCA. The longer the molecular length of PIB, the higher its effect on improving fuel combustion efficiency. In this study, there are 2 type of PIB being used with molecular weight of 950 and 1300 and 2 type of amine, tetraethylenepentamine and diethylenetriamine. The synthesized result is being tested to acquire its physical-chemical properties and also its performance as DCA in one-cylinder gasoline engine with fuel.

Produce high yield of ETBE using acid catalyst and analyzed its performance. ETBE synthesis is carried out under gas phase reaction in a fixed bed reactor using H-ZSM5 catalyst. The product is condensed into liquid. Results show, this product have concentration of ETBE, up to 60% and yield up to 12%. At 300 ppm of this additive mixed with gasoline is tested in motorcycle engine for 30 hours to inspect the combustion performance. The test shows deposit formation in intake valve fewer rather than other gasoline. Comparing to MTBE and ethanol, it shows better improvement, by decreasing the rate of CO emission and deposit formation on intake valve.

Solid waste of Spent Bleaching Earth (SBE) containing a small amount of oil is generated in the processing Crude Palm Oil (CPO) into cooking oil. Recovery of the oil from SBE from extraction process can produce SBEO (spent bleaching oil), a low-grade oil which has dark color, contain significant amount of FFA (free fatty acid) and solidified at ambient temperature. In this research, this SBEO is utilized as biolubricant after treating through 2 step of processes. The first step is the conversion of SBEO into methyl ester by decolorization, FFA reduction, and transesterification processes. The second step is conversion of methyl ester into ethylene glycol ester. Transesterification of the SBE into methyl ester by methanol at ratio 1:6, give yield of 99.74. While second step transesterification of methyl ester into ethylene glycol is conducted by ethylene glycol. Temperature of 170°C has the best result of yield (93%). Physical characteristic of the ethylene glycol product give density at 40°C of 0.91 gr/cm3 and viscosity (at 40°C) of 9,75 cSt, flash point of 252°C, pour point of -7°C. This Physical characteristic meet the standard SNI 7069.9-2016 for hydraulic lubricant

One potential and useful product of Indonesia's biodiversity is fibroin which extracted from silkworm cocoons of Bombyx mori L (silk fibroin). Silk fibroin, in which has capability to fuse into the human body, is used for bone graft or wound healing dressing. In the dentistry, researchers develop silk fibroin as a dental treatment material for pulp perforation teeth case. The dental treatment material developed from silk fibroin is expected to overcome the limitation of existing materials. The purpose of this study was to determine the molecular weight and structural characteristics identification of silk fibroin as a preliminary study before being used as dental material. This research used two methods, which were sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS PAGE) and Fourier transform infrared Spectroscopy (FTIR). The result showed that there was an expression of electrophoresis bands on the molecular weight of 10 – 55 kDa, while the FTIR showed the peak spectra of fibroin sample was at 3309.80 cm-1. Based on its molecular weight and structure characteristic, fibroin consists of an NH group of protein that consists of several amino acids.

Candida rugosa lipase (CRL, EC Number: 232–619-9) is a stable enzyme, and its use is relatively widespread in the field of biotechnology, especially in hydrolysis reactions, esterification, transesterification and enantioselective biotransformation. This study examined the role of CRL as a biocatalyst for L-lactide ring-opening polymerization in the production of metal-free polylactic acid (PLA). The ring-opening polymerization reaction was conducted at various temperatures (70, 90, 110 and 130 °C) and CRL concentrations (1, 2, 3 (%w/w)). The results revealed a strong relationship between PLA formation and CRL activity. The highest CRL activity was obtained in ring-opening polymerization of L-lactide at a temperature of 90 °C and concentration of 2% (w/w). Under these conditions, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) of PLA analyzed by gel permeation chromatography was highest at 5428 and 2854 g/mol respectively, with a yield of 93% and the enzyme activity 0.39 U. The polymerization of lactide at 90 °C occurred only in the presence of the catalyst. The crystallinity and melting point of PLA were 31% and 120 °C, respectively. Scanning electron microscopy (SEM) analysis of the morphology of PLA revealed smooth and uniform pores in each region, with mass percentage of the elements carbon (C) and oxygen (O) of 52% and 48%, respectively.

The corrosion inhibition of rice husk extract for bio-corrosion in mild steel in 1 M of H2SO4 solution and the effect of adding potassium iodide were investigated using the weight-loss method with a variable solution temperature and various bio-inhibitor concentrations. The addition of potassium iodide can significantly increase the efficiency of rice husk extract. The highest efficiency is 95.89% at 1,250 ppm of inhibitor concentration at a temperature of 313 K. The inhibition efficiency of rice husk extract is synergistically increased with the addition of potassium iodide. The characteristics of the adsorption inhibitors were assessed using the Langmuir isotherm adsorption approach at all studied concentrations and temperatures. The synergy of rice husk extract and potassium iodide was examined using thermodynamic and kinetic parameters. Copyright © 2019 BCREC Group. All rights reserved

The esterification of kemiri sunan (Aleurites trisperma sp.) oil with TiO2 photocatalyst was studied. Kemiri sunan oil is non-edible oil with high content of free fatty acid (FFA), which needs esterification and followed by transesterification process to improve methyl ester yield. Esterification was conducted to reduce FFA content in the oil by reacting them with methanol to produce methyl ester. In this study, esterification is conducted in photocatalytic reactor using TiO2 photocatalyst in the presence of UV light. Many parameters effected to the conversion of FFA, but in this study it was limited in reaction time, ratio methanol and ratio TiO2. The aim of this study was to obtain the optimum condition of those parameters. Experimental result showed that the optimum condition of esterification achieved at ratio of catalyst to oil 0.4% (w/w), ratio between oil and methanol 1:36, and reaction time 60 minutes. the conversion of FFA into methyl ester was 83.45% (FFA decrease from 29.79% to 4.93%). Photocatalytic esterification is prospective because it needs shorter time, do not require neutralization, also in the end the catalyst and methanol could be recycled. Esterification product was characterized with FTIR.

Animal products with high fat content are generally correlated with several human diseases including coronary heart disease, hypertension and arteriosclerosis. However, some unsaturated fatty acids are considered to have pivotal role in human health. As a consequence, many studies were conducted to reduce fat and increase some unsaturated fatty acid content in animal products. This study investigated the use of phytonutrition (duckweed) as feed ingredient on fat and fatty acids composition of Muscovy duck (Cairina moschata domestica L.) meat. Results showed that the use of 1% duckweed significantly increased the linoleic acid content of carcass while reducing the fat level. This result might suggest that duckweed can be used as an alternative feed ingredient to produce a healthy poultry meat.

Terminalia catappa leaves extract has a high content of polyphenol compounds. Polyphenol compounds inhibit the corrosion rate for mild steel. This study aimed to assess the ability of terminalia catappa leaves extract to inhibit bio-corrosion on the surface of mild steel placed in a corrosive medium of 1M sulphuric acid, and to compare this with that of tannin and sodium phosphate. The method used was the loss of weight at temperatures of 313K, 333K and 353K. It found that the inhibition efficiency was susceptible to increased temperature. The efficiency of bio-corrosion inhibition of sodium phosphate> tannin>Terminalia catappa leaves extract; that is, the ability of Terminalia catappa leaves extract to inhibit bio-corrosion was relatively lower than that of tannin and sodium phosphate. Terminalia catappa leaves extract’s inhibiting corrosion rate of mild steel was very good at 333K and 1250 ppm concentration, with an efficiency inhibition of 64%. The adsorption mechanism is a Langmuir isotherm, and the process is endothermic and spontaneous.

Lactide is the monomer for the polymer polylactic acid (PLA) from lactic acid through polycondensation and depolymerization process. The properties of PLA strongly depend on the quality of the lactide monomer from which it is synthesized. Optical purity of lactide produced in depolymerization process confirmed to be L-lactide. The highest yield of crude lactide was 38.5% at temperature 210 °C with average molecular weight (Mn) of oligomer was 2389. Ring opening polymerization of lactide using Candida rugosa lipase as biocatalyst to PLLA synthesis has been achieved to generate useful biomedical materials free from heavy metal.

Hydrodeoxygenation of oleic acid as model compound of vegetable oils over Pd/zeolite catalysts was investigated under conditions of 375−400 °C and 15 bar in a semi batch stirred autoclave reactor. Pd/zeolite-1 and Pd/zeolite-2 catalysts were prepared using microwave polyol method with different treatment conditions. The liquid hydrocarbon products named Renewable Diesel have suitable density and viscosity, and quite high cetane index in accordance with standard commercial diesel and ASTM D-975. The IR spectrum of Renewable Diesel products have similarities with commercial diesel. The oxygenation removal pathway of oleic acid over Pd/zeolite 1 catalyst was primarily compiled through decarboxylation at 375 °C.

The added value of the waste of Rama shrimp (Thalassina anomala) carapace could be increased by extracting it to be a chitosan through the stages of demineralization, deproteination and deacetylation. The aim of the research was to determine the ability of chitosan extracted from the carapace to inhibit the growth of pathogenic bacteria. Chitosan extracted from the shrimp carapace was showing its chemical characteristics, namely: the content of water 6.74%, ash 4.13%, nitrogen 7.5%, and deacetylation degree 71%. Chitosan was dissolved in 1% acetic acid. Antibacterial activity testing was carried out by using the well diffusion method, conducted by addition of chitosan at varied concentration (0%, 1%, 2%, 4% and 6%). The results showed that the chitosan had an ability to be antibacterial against Salmonella thypi, Escherichia coli, Staphylococcus aureus and Bacillus cereus. It was indicated by the clear zones formed around the well. The clear zone formed was indicating that the chitosan extracted from the carapace could inhibit the growth of pathogenic bacteria at a concentration of 1 %. The average of inhibition zone diameter for each bacterium was 11.54 mm, 11.46 mm, 7.78 mm, and 9.84 mm, respectively.

In this research, carbon nanotubes (CNT) fabrication is attempted by using existing home-made Plasma Enhanced Chemical Vapour Deposition (PECVD) system. The fabrication is a catalytic growth process, which Fe catalyst thin film is grown on the Silicon substrate by using dc-Unbalanced Magnetron Sputtering method. By using methane (CH4) as the source of carbon and diluted silane (SiH4) in hydrogen as the source of hydrogen with 10:1 ratio, CNT fabrications have been attempted by using Very High Frequency PECVD (VHF-PECVD) method. The fabrication processes are done at relatively low temperature, 250oC, but with higher operated plasma frequency, 70 MHz. Recently, it is also been attempted a fabrication process with only single gas source, but using one of the modification of the VHF-PECVD system, which is by adding hot-wire component. The attempt was done in higher growth temperature, 400oC. Morphological characterizations, by using Scanning Electron Micrograph (SEM) and Scanning Probe Microscopy (SPM), as well as the composition characterization, by using Energy Dispersion Analysis by X-Ray (EDAX), show convincing results that there are some signatures of CNT present.

An analytical expression of direct tunneling time of an electron through a nanometer-thick trapezoidal barrier has been derived. It is found that the direct tunneling time is independent of the thickness of the SiO2 barrier for the SiO2 layers thicker than 1 nm, which are used in advanced MOS (metal-oxide-semiconductor) devices. By applying a voltage to the barrier layer, the direct tunneling time becomes shorter than that obtained without the applied voltage. The nonparabolic energy-momentum dispersion of the barrier layer increases the direct tunneling time as compared to the parabolic one. However, the nonparabolic effect is negligible for high electron energy. It is also shown that the tunneling time obtained by the phase time is shorter than that calculated by the semiclassical approach for high electron energy. However, both of the calculated tunneling times have not been able to explain the reason why the calculated tunneling time are orders of magnitude shorter than the highest time resolution achievable in the siliconbased MOS devices. � 2005 Elsevier Ltd. All rights reserved.

We present an L^2 discretization of the helium atom using a non-orthogonal Laguerre function basis. The frozen-core approximation is used to calculate the helium atom Hamiltonian. The resulting three-term recurrence relation is a special case of the recurrence relation of the Pollaczek polynomials which is a set of orthogonal polynomials having a non-empty continuous spectrum in addition to an infinite discrete spectrum. The completeness of the helium atom wave functions obtained is studied in terms of weights of the Gauss quadrature.

The Hot Wire Cell PECVD method has been developed and successfully applied to grow the hydrogenated amorphous silicon (a-Si:H) thin films with a relatively high conductivity. The a-Si:H thin films were grown on the 7059 corning glass at a filament temperature of 800 oC. Ten percents silane (SiH4) gas diluted in hydrogen (H2) gas was used as gas source. In the hot wire cell PECVD method, reactant gases are decomposed as a result of reaction with a heated filament. The filament was placed parallelly with inlet gas system and outside of electrodes. The characterization results exhibited that the deposition rate increased from 1.02 Å/s to 1.90 Å/s with increasing the rf power from 80 watt to 120 watt. The optical bandgap decreased from 1.65 eV to 1.56 eV with increasing the rf power from 80 watt to 120 watt. The SEM image and the XRD spectrum exhibited the transition of amorphous to microcrystalline silicon at an rf power of 120 watt. The transition of amorphous to microcrystalline was indicated by the reduction of amorphous parts and the appearance of peak diffraction at preferential crystal orientation. The dark and photo conductivities of the obtained μc-Si:H thin films was 6.84x10-6 S cm-1 and 4.16x10-4 S cm-1, respectively.

Polyvinyl alcohol and polyvinyl pyrrolidone (PVA–PVP) blended hydrogel for wound dressing has been prepared by using gamma rays irradiation technique. The gel fraction, mechanical properties, the water content and water absorption performance of the hydrogels were measured. It was found that the gel fraction increases with increasing irradiation dose but never reaches 100% of gel. The PVA/PVP blended hydrogel has a water content in the range between 60% and 80% and water absorption between 40% and 250%. The water vapor transmission rate value (WVTR) of the PVA/PVP blended hydrogel varies between 50 and 200 g/m2/h. The hydrogel could be considered as good barrier against microbes. According to in vitro assessment it was found that the PVA/PVP blended hydrogel was very useful material that can meet the efficacy requirement and its healing rate was comparable with sterilized gauze and sofratulle.

The characterization of dressing component materials and radiation induced formation of PVA–PVP hydrogel have been carried out. It was found that the purity of PVA and PVP powders were 99.5% and 77.82% based on DSC measurement. The PVA–PVP hydrogels have the water content in the range of 60–80% and water absorption in the range of 40–250%. It was also found that the PVA–PVP hydrogel prepared by irradiation at 20 kGy shows a good barrier for microbes. This characterization are very important for PVA–PVP hydrogel to be used as wound dressing.

Oxidative degradation of mineral oil under tribocontact is investigated in comparison with static oxidation. A rolling four-ball apparatus lubricated with a small amount of sample oil (approximately 10 mg) was selected as the method for degrading oil samples. Applications of very small amounts of sample oils made it possible to detect small amounts of degradation product after friction tests. An FTIR analysis and gel permeation chromatography were used to characterize the degraded oils. It was found that mineral oil oxidatively degraded during tribo-operation at nominally moderate temperatures. The effect of oxidation inhibitors on the tribodegradation of mineral oil was investigated. A hindered phenol inhibitor, which acts as a radical scavenger, and a sulfur compound inhibitor, which acts as a hydroperoxide decomposer, were used. No inhibition was observed in the tribodegradation of mineral oils with either of two inhibitors, though they were effective for the static oxidation. It was also found that th...

An electron direct tunneling current model of n+- poly - Si/SiO2/p - Si(100) metal-oxide-semiconductor (MOS) capacitors has been developed by considering a parallel-perpendicular kinetic energy coupling, which is represented by the gate electron phase velocity, and anisotropic masses under a parabolic E-k dispersion relationship. The electron effective mass in the oxide and the electron phase velocity in the n+ poly-Si gate are the only two fitting parameters to compare calculated tunneling currents to measured ones. It was obtained that the calculated tunneling currents fit well to the measured ones. The electron effective mass in the oxide layer tends to increase with decreasing the oxide thickness. In addition, the gate electron velocity is a constant of 1x10(5)m/s. Moreover, the theoretical model offers a simple treatment and an accurate result in obtaining the tunneling current.

Ti1−xCOxO2 thin films have been grown on n‐type Si(100) substrates by metal organic vapor deposition (MOCVD) using titanium (IV) isopropoxide (TTIP) and tris (2,2,6,6‐tetramethyl‐3, 5‐heptanedionato) cobalt (III) as metal organic precursors. The parameter deposition, such as: bubbler temperature of TTIP Tb(Ti) = 50 °C; substrate temperature Ts = 450 °C; bubbler pressure Pb(Ti) = 260 Torr; flow rate of Ar gas through TTIP precursor Ar(Ti) = 100 sccm (standard cubic centimeters per minute) and flow rate of oxygen gas O2 = 60 sccm were found as optimal deposition parameters. The thin films deposited were have rutile (002) crystal plane, whereas those deposited at other parameter were mixing of anatase and rutile phases. Co dopant with concentration of up to 5.77% was not changes the structure of TiO2. Increase of Co incorporated in thin films was decreasing of band‐gap energy.

It is explained one of the carbon nanotube research progress in Indonesia. It is being attempted a carbon nanotube growth using the modifications of existing home made PECVD system, which are Very-High Frequency PECVD (VHF-PECVD) and Hotwire VHF-PECVD (HW-VHF-PECVD). They are catalytic growth processes, which various metal catalyst thin films were growth on the Silicon substrate, such as Fe catalyst grown by using dc-Unbalanced Magnetron Sputtering Method and Al as well as Ni catalyst grown by high vacuum thermal evaporation method. SiO2 buffer layer was also grown beneath the Al catalyst layer. Some post-treatments for the catalyst thin films were also conducted, which were post- annealing process under various atmosphere conditions, N2, NH3 and free air. By using a single gas source, which was methane as the source of carbon, a carbon nanotube fabrication has been attempted at relatively low temperature, 400degC. It was expected that the high value of plasma frequency could lead to higher dissociation rate of methane to produce much carbon radicals. Meanwhile, the usage of hot-wire filament was expected to pre-decompose some the methane gas before reach the reactor in order to produce some of hydrogen radicals, which might be needed for CNT growth process. From morphological characterization results, it has been achieved some carbon sub-microstructure, in 100 nm of grain size and vertically aligned. From the composition characterization results, it has been confirmed that carbon atoms fraction were quite significant and the catalytic growth mechanism was happened. Furthermore, from the SEM characterization results of the samples, which was grown on the buffered catalyst, showed that a long aligned horizontal carbon nanotube has been grown.

Two different components of tunneling current in the TiN/HfSiOxN/SiO2/p-Si(100) metal-oxide-semiconductor capacitor have been presented. The tunneling currents were calculated by taking into account a longitudinal-transverse kinetic energy coupling. The calculated tunneling currents were compared with that measured ones by employing the electron and hole effective masses and phase velocities as fitting parameters. It has been shown that hole tunneling currents dominate at low voltages whereas at high voltages the tunneling currents are mainly contributed by electrons. It has also been found that the effective mass of hole in the HfSiOxN layer is higher than that of electron. The gate electron and substrate hole velocities are 1×105 m/s independent of the HfSiOxN thickness. In addition, it is speculated that the electron and hole effective masses in the HfSiOxN layer perhaps increase as its thickness decreases.

A theoretical model of an electron tunneling current in an anisotropic Si/Si1−xGex/Si heterostructure was developed. The parallel and perpendicular kinetic energies were coupled and the coupling was included in expressing the electron transmittance through the anisotropic heterostructure. The model was applied to the anisotropic Si(1 1 0)/Si0.5Ge0.5/Si(1 1 0) heterostructure with a 25 nm thick strained Si0.5Ge0.5 potential barrier, in which each layer of the heterostructure has three valleys (valleys 1, 2 and 3) with different inverse effective mass tensors and a conduction band discontinuity of 216 meV. The Si(1 1 0)/SiGe structure implies that only the four equivalent valleys (valleys 1 and 2) are considered in calculations. It was found that the transmittance for valley 1 is the same as that for valley 2 due to the same barrier height. The transmittance decreases as the electron phase velocity increases because the electron phase velocity enhances the barrier height. Moreover, the total tunneling current density for the phase velocity higher than 3 × 105 m s−1 differs significantly from that obtained without including the kinetic energy coupling. As the electron phase velocity gets higher, the total tunneling current density lowers. This implies that the coupling effect cannot be ignored for electrons with high phase velocity.

Cl and Ar ions have been implanted, at 30 keV and at various incidence angles, into Si substrates maintained at room temperature during implantation. Implantation induced Si disorder was measured using RBS channelling. The effects upon disorder of various incidence angles were studied over a fluence range of 1012-6·1015 ions·cm−2 The results show that, at low fluences Cl and Ar ion implantations generate a bimodal disorder-depth profile, whilst at higher fluences measurements of amorphised layer thickness as a function of ion incidence angle allow values of the standard deviation of the disorder profile parallel and transverse to the ion beam direction for each ion to be obtained with good agreement to theoretical predictions. The disorder-fluence behaviour under these conditions is ion species independent.

Ne, Ar, Sb, and Xe ions have been implanted, at 30 keV or 80 keV and at various incidence angles, into Si substrates maintained at room temperature during implantation. Implantation-induced Si disorder was measured using RBS-channelling. The effects upon disorder of various incidence angles were studied over a fluence range of 1012-1016 ions·cm−2. The results show that, at low fluences the lighter (Ne) and slightly heavier (Ar) ion implantations generate a bimodal disorder-depth profile, whilst at higher fluences measurements of amorphised layer thickness as a function of ion incidence angle allow values of the standard deviation of the disorder profile parallel and transverse to the ion beam direction for each ion to be obtained with good agreement to theoretical predictions.