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Efektivitas Polyvinyl Acetate (PVAc) Sebagai Matriks Pada Komposit Sampah Masturi, Masturi; Mikrajuddin, Mikrajuddin; Khairurrijal, Khairurrijal
BERKALA FISIKA Vol 13, No 2 (2010): Berkala Fisika
Publisher : BERKALA FISIKA

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It was fabricated a composite using solid waste as filler and polyvinyl acetate (PVAc) as matrice. This work is as a solution of more serious solid waste problems. The solid waste used is paper waste and leaf one with their composition are 60% and 40% respectively. The crushed-solid waste then hot-pressed at 100 MPa of pressure and 150Â°C of temperature. Then, the compressive strength of composite before and after PVAc presence was investigated to get a composition in which the compressive strength is optimum. Â Keywords: composite, solid waste, polyvinyl acetate, compressive strength.

Effect of Thickness and Temperature of SiO2 Layer on Leakage Currents in MOS Capacitor Materials with High Dielectric Constant by Involving the Charge Trap Noor, Fatimah A.; Masturi, Masturi; Abdullah, Mikrajuddin; Khairurrijal, Khairurrijal
Jurnal ILMU DASAR Vol 15 No 1 (2014)
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Jember

Modeling of the leakage current in a field-effect transistor metal-oxide-semiconductor (MOSFET) with high dielectric material has been developed by taking into account the effect of charge traps formed at the interface of high-k material/SiO2. Transmittance calculated using Airy wave function approach and involving the anisotropic electron mass and the effect of coupling between transverse and longitudinal energy represented by the speed of the electrons in the metal gate. Transmittance obtained is then used to calculate the leakage current in the structure of n+Poly-Si/HfSiOxN/trap/SiO2/p-Si for oxide voltage variations, temperature, and thickness of the SiO2. From the calculation that the leakage current decreases with decreasing of oxide voltage and increasing of the thickness of the oxide layer of SiO2. Also obtained that the temperature of the device does not give a great influence on the change of leakage current. Keywords: Leakage current, electron speed, charge traps

Numerical Simulation of Tunneling Current in an Anisotropic Metal-Oxide-Semiconductor Capacitor Noor, Fatimah Arofiati; Iskandar, Ferry; Abdullah, Mikrajuddin; khairurrijal, Khairurrijal
Indonesian Journal of Electrical Engineering and Computer Science Vol 10, No 3: July 2012
Publisher : Institute of Advanced Engineering and Science

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In this paper, we have developed a model of the tunneling currents through a high-k dielectric stack in MOS capacitors with anisotropic masses. The transmittance was numerically calculated by employing a transfer matrix method and including longitudinal-transverse kinetic energy coupling which is represented by an electron phase velocity in the gate. The transmittance was then applied to calculate tunneling currents in TiN/HfSiOxN/SiO2/p-Si MOS capacitors. The calculated results show that as the gate electron velocity increases, the transmittance decreases and therefore the tunneling current reduces. The tunneling current becomes lower as the effective oxide thickness (EOT) of HfSiOxN layer increases. When the incident electron passed through the barriers in the normal incident to the interface, the electron tunneling process becomes easier. It was also shown that the tunneling current was independent of the substrate orientation. Moreover, the model could be used in designing high speed MOS devices with low tunneling currents.Â DOI:Â http://dx.doi.org/10.11591/telkomnika.v10i3.607

Sintesis Nanokomposit -Fe2O3/SiO2 dengan Metode Salt-Assisted Spray Pyrolysis untuk Menurunkan Viskositas Minyak Berat Anrokhi, Mohamad Samsul; Nuryadin, Bebeh Wahid; Abdullah, Mikrajuddin; Khairurrijal, Khairurrijal; Iskandar, Ferry
Jurnal Matematika dan Sains Vol 22 No 1 (2017)
Publisher : Institut Teknologi Bandung

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A α-Fe2O3/SiO2 nanocomposite as aquathermolisys catalyst material at heavy oil has been synthesized and optimized by using  Salt-Assisted Spray Pyrolysis method. The α-Fe2O3/SiO2 nanocomposite is obtained by thermal decomposition from the precursor.  The precursor is made of FeCl3, SiO2 and NaCl and water as a solvent. Concentration of FeCl3, SiO2, and NaCl are 1:1:5 in order. the composition of SiO2 in the composite is 0%, 25% and 50% of total mass, respectively. the droplets were transported to the furnace reactor using air as a carrier gas with a fixed flow rate at 5 liter/min and the furnace’s temperature is 800 °C in order to get the pyrolysis reaction. The resulted powder is then characterized by using XRD, SEM and Chatalytic aquathermolysis test. The result of XRD characterization shows that crystal peaks of α-Fe2O3 has been formed. SEM result shows nanocomposite morphology of α-Fe2O3/SiO2 with circle particle form with average particle diametre of α-Fe2O3, SiO2 25% and SiO2 50% of total mass are 765 nm, 850 nm, and 746 nm, respectively. Catalytic Aquathermolysis test showed catalyst α-Fe2O3/SiO2 50%  has catalytic properties better than catalytic properties of α-Fe2O3/SiO2 and α-Fe2O3/SiO2 25%.

Aktivitas Fotokatalitik TiO2 yang Dilapiskan pada Polipropilena Berbentuk Lembaran dan Butiran Sutisna, Sutisna; Rokhmat, Mamat; Wibowo, Edy; Rahmayanti, Handika Dany; Khairurrijal, Khairurrijal; Abdullah, Mikrajuddin
Jurnal Matematika dan Sains Vol 22 No 1 (2017)
Publisher : Institut Teknologi Bandung

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The sheet and granule of polypropylene (PP) have been used as the support material for TiO2 catalyst. The TiO2 powder was coated to the polymer surface using a combination of electrostatic and heating methods (for the PP sheet) and thermal milling method (for PP granule). The photocatalytic testing of catalysts conducted on a 300 ml solution of Methylene Blue (MB) with initial concentration of 25 ppm. Under solar ilumination, the catalyst sheets have a higher photocatalytic activity than the catalyst granules.

Pengaruh Perbandingan Molaritas Prekursor terhadap Fotoluminesensi BCNO yang Disintesis dengan Metode Hidrotermal Septia Mahen, Ea Cahya; Nuryadin, Bebeh Wahid Nuryadin Wahid; Iskandar, Ferry; Abdullah, Mikrajuddin; Khairurrijal, Khairurrijal
Jurnal Matematika dan Sains Vol 18 No 3 (2013)
Publisher : Institut Teknologi Bandung

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Abstrak Fosfor BCNO yang terdispersi pada likuid telah berhasil disintesis menggunakan metode hidrotermal. Bahan dasar (prekursor) yang digunakan adalah asam borat [B(OH)3] sebagai sumber boron, urea [(NH2)2CO] sebagai sumber nitrogen, dan asam sitrat (C6H8O7)sebagai sumber karbon. Dalam penelitian ini, telah dilakukan variasi rasio molar nitrogen terhadap boron (N/B) dan rasio molar karbon terhadap boron (C/B) dan pengaruhnya terhadap pendaran fosfor BCNO yang dihasilkan. Hasil karakterisasi spektrum fotoluminesen dari sampel yang dibuat menunjukkan bahwa pendaran fosfor BCNO mempunyai puncak emisi tunggal disekitar warna biru (~450 nm) ketika dieksitasi dengan sinar UV(365 nm). Intensitas pendaran dipengaruhi oleh kadar karbon terhadap kandungan boron (C/B) dan kadar nitrogen terhadap kandungan boron (N/B). Penambahan kadar karbon dan nitrogen diketahui dapat meningkatkan intensitas pendaran. Sedangkan intensitas optimum pendaran fosfor BCNO dicapai pada saat ratio molar C/B = 1 dan N/B =20. Kata kunci: Fosfor BCNO, Spektrum fotoluminesen, Metode hidrotermal. Influence of Precursor Molar Ratio on the BCNO Photoluminescence synthesized by Hydrothermal Method Abstract BCNO phosphor which is dispersed into liquid has been successfully synthesized by using hydrothermal method. The precursor consists of the borate acid [B(OH)3] as boron source, urea [(NH2)2CO] as nitrogen source, and citric acid (C6H8O7) as carbon source. In this research, molar ratio variations of nitrogen and carbon towards boron (N/B and C/B), and their influence on resulted BCNO phosphor luminescence were done. The characterization results of the sample shows the single peak of BCNO phorphorous luminescence around blue color (~450 nm) on the photoluminescence spectrum, when excited by UV light (365nm). The photoluminescence intensity was affected by the ratio N/B and C/B. The increase of carbon and nitrogen ratio can increase the photoluminescence intensity. The optimum intensity of BCNO phosphor photoluminescence was obtained at the molar ratio N/B = 20 and C/B =1. Keywords : BCNO phosphor, Photoluminescence spectrum, Hydrothermal method.

Arus Terobosan Pada Transistor Dwikutub Struktur Hetero Si/Si1-xGex/Si Anisotropik Melewati Basis Tergradasi (Graded Base) Hasanah, Lilik; Khairurrijal, Khairurrijal
BERKALA FISIKA Vol 13, No 2 (2010): Berkala Fisika, Edisi Khusus
Publisher : BERKALA FISIKA

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Tunneling current in bipolar transistors Si/Si1-xGex/Si anisotropic hetero structure for germanium conditions on a constant basis is not analyzed here. The concentration of germanium in the base which is not constant will result in the potential profile at the base is not flat, but will be graded according to the germanium concentration. Tunneling current calculation is performed semi-analytically and numerically. The calculation result obtained then matched with experimental data. The results show that the results of analytical calculations with results of semi-numerical calculations. While analytical calculations with experimental data only flows from the VBE 0.3 to 0.6 V. Â Keywords: Tunneling current, germanium concentration, anisotropic material, transfer matrix method, hetero structure bipolar transistor

Arus Terobosan Pada Transistor Dwikutub Struktur Hetero Si/Si1-xGex/Si Anisotropik Melewati Basis Tergradasi (Graded Base) Hasanah, Lilik; Khairurrijal, Khairurrijal
BERKALA FISIKA Vol 13, No 2 (2010): Berkala Fisika
Publisher : BERKALA FISIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (259.483 KB)

Tunneling current in bipolar transistors Si/Si1-xGex/Si anisotropic hetero structure for germanium conditions on a constant basis is not analyzed here. The concentration of germanium in the base which is not constant will result in the potential profile at the base is not flat, but will be graded according to the germanium concentration. Tunneling current calculation is performed semi-analytically and numerically. The calculation result obtained then matched with experimental data. The results show that the results of analytical calculations with results of semi-numerical calculations. While analytical calculations with experimental data only flows from the VBE 0.3 to 0.6 V. Â Keywords: Tunneling current, germanium concentration, anisotropic material, transfer matrix method, hetero structure bipolar transistor

Transmission Coefficient of an Electron through a Heterostructure with Nanometer-Thick Trapezoidal Barrier Grown on an Anisotropic Material Hasanah, Lilik; Noor, Fatimah A.; Khairurrijal, Khairurrijal; Abdullah, Mikrajuddin; Winata, Toto; Sukirno, Sukirno
Journal of Mathematical and Fundamental Sciences Vol. 38 No. 1 (2006)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2006.38.1.3

Transmission coefficient of an electron incident on a heterostructure potential with nanometer-thick trapezoidal barrier grown on anisotropic materials are derived by solving the effective-mass equation including off-diagonal effective-mass tensor elements. The boundary condition for an electron wave function (under the effective-mass approximation) at a heterostructure anisotropic junction is suggested and included in the calculation. The analytic expressions are applied to the Si(110)/Si0.5Ge0.5/Si(110) heterostructure, in which the SiGe barrier thickness is several nanometers. It is assumed that the direction of propagation of the electrons makes an arbitrary angle with respect to the interfaces of the heterostructure and the effective mass of the electron is position dependent. The transmission coefficient is calculated for energy below the barrier height, varying the applied voltage to the barrier. The transmission coefficient depends on the valley where the electron belongs and it is not symmetric with respect to the incidence angle.

FERROELECTRIC PROPERTIES OF BaBi4Ti4O15 DOPED WITH Pb2+, Al3+, Ga3+, In3+, Ta5+ AURIVILLIUS PHASES Rosyidah, Afifah; Onggo, Djulia; Khairurrijal, Khairurrijal; Ismunandar, Ismunandar
Indonesian Journal of Chemistry Vol 9, No 3 (2009)
Publisher : Universitas Gadjah Mada

In recent years, the ferroelectric properties of aurivillius oxides have attracted interest and an extensive amount of work has been done toward the realization of their potential application in nonvolatile memories (FeRAM: ferroelectric random access memory). Recently, we have carried out computer simulation in atomic scale in order to predict the energies associated with the accommodation of aliovalent and isovalent dopants (Pb2+, Al3+, Ga3+, In3+, Ta5+) in the aurivillius structure of BaBi4Ti4O15. In this work, the predicted stable phases were synthesized using solid state reactions and their products then were characterized using powder X-ray diffraction method. The cell parameters were determined using Rietveld refinement in orthorhombic system with space group of A21am. Results from the ferroelectric properties measurement of BaBi4Ti4O15 were also presented. The cell parameters for BaBi4Ti4O15 doped with Pb2+, Al3+, Ga3+,In3+, Ta5+ were a = 5.47116(4) b = 5.45636(5) c = 41.8649(3) Ã…; a = 5.47104(4) b = 5.45634(4) c = 41.8640(3) Ã…; a = 5.47112(4) b = 5.45648(4) c = 41.8643(3) Ã…; a = 5.47111(4) b = 5.45645(5) c = 41.8649(3) Ã…; and a = 5.47134(4) b = 5.45588(4) c = 41.8639(5) Ã…. The ferroelectric properties measurement for BaBi4Ti4O15 doped with Pb2+, Al3+, Ga3+,In3+, Ta5+ showed that the Pr = 15.225 mC/cm2, Ec = 33.96 kV/cm; Pr = 15.925 mC/cm2, Ec = 35.724 kV/cm; Pr = 16.625 mC/cm2, Ec = 36.504 kV/cm; Pr = 15.57 mC/cm2, Ec = 32.925 kV/cm; Pr = 17.2827 mC/cm2, Ec = 37.44 kV/cm.

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