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All Journal Jurnal Natur Indonesia Perfecting a Video Game with Game Metrics JURNAL FISIKA Jurnal Matematika & Sains Journal of Engineering and Technological Sciences Ta'allum: Jurnal Pendidikan Islam Jurnal Otomasi, Kontrol, dan Instrumentasi Indonesian Journal of Electrical Engineering and Computer Science Physics Communication Prosiding SNAST
Mikrajuddin Abdullah
Institut Teknologi Bandung
Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Education Electrical & Electronics Engineering Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mathematics Mechanical Engineering Physics

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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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Abstract

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. DOI: http://dx.doi.org/10.11591/telkomnika.v10i3.607
Pengaruh Temperatur Penumbuhan terhadap Struktur Kristal dan Morfologi Film Tipis TiO2:Eu yang Ditumbuhkan dengan Metode MOCVD [The Effect of Growth Temperature on the Crystall Structure and Morphology of the Thin Film TiO2:Eu Grown with MOCVD Method] Edy Supriyanto; Goib Wiranto; Hery Sutanto; Agus Subagio; Mikrajuddin Abdullah; Maman Budiman; Pepen Arifin; Sukirno Sukirno; Mohamad Barmawi
Jurnal Matematika & Sains Vol 12, No 2 (2007)
Publisher : Institut Teknologi Bandung

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Thin film of TiO2:Eu had been grown on an n-type Si(100) substrate using Metalorganic Chemical Vapor Deposition (MOCVD) method with titanium (IV) isopropoxide [Ti{OCH(CH3)2}4] 99.99% and europium nitrate [Eu(NO3)3.6H2O] 99.99% as the metal organic precursors. The tetrahydrofuran (THF) was used as a solvent for the precursor. X-ray Diffraction (XRD) analysis showed that the TiO2:Eu thin film grown at temperature of 450 οC had crystal planes of rutile (200), rutile (002) and anatase (211), whereas film grown at 500 οC resulted in a crystal plane of rutile (002) with columnar grain and surface morphology relatively smooth. On the other hand, film grown at temperature of 550 οC has rutile (200) and rutile (002) planes. The surface morphology of thin films TiO2:Eu was affected by Eu atom concentration. The roughness of surface morphology increased with increasing Eu content and therefore the grains became larger. It can be concluded that the crystal structure and surface morphology properties of the films depended significantly on the substrate temperature.
Size Dependent Phase Transition in BaTiO3 and PbTiO3: a General Theory Based on a Simple Ising Model Mikrajuddin Abdullah
Jurnal Matematika & Sains Vol 9, No 1 (2004)
Publisher : Institut Teknologi Bandung

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A general theory based on simple Ising model has been developed to explain the effect of size on the phase transition in BaTiO3 and PbTiO3. The model can explain very well the presence of critical temperature for the occurrence of tetragonal ⇔ cubic structure, the presence of critical size where this transition to occur. Size dependent of the transition is induced by the dependence of dipole-dipole interaction in the sample on the size.
Gelation Model for Porosity Dependent Fluid Permeability in Porous Materials Mikrajuddin Abdullah; Khairurrijal Khairurrijal
Jurnal Matematika & Sains Vol 14, No 1 (2009)
Publisher : Institut Teknologi Bandung

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A statistical theory of gel formation in a polymer matrix was used to explain the dependence of liquid permeability in porous materials. A porous material was modeled as a dispersion of bubbles in a solid matrix. Bubbles were treated as monomers and formation of infinite connected bubbles was treated as the formation of gels in polymer. The theoretical predictions were in agreement with the observed data for basalt andesits. The model can easily predict the percolation threshold of porosity at which the permeability increases suddenly, which depends on the effective number of nearest bubbles around a selected bubble. Around the percolation threshold, the permeability satisfies a scaling relationship with a critical exponent of t » 1.2. It is also identified that the critical exponent and fractal dimension of pores, D, satisfy t » 0.8 (1 + 1/D).
Dinamika Paket Gelombang Elektron yang Menerobos Penghalang Trapesium dengan Ketebalan Nanometer Maharati Hamida; Khairurrijal Khairurrijal; Mikrajuddin Abdullah
Jurnal Matematika & Sains Vol 11, No 2 (2006)
Publisher : Institut Teknologi Bandung

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A simulation of the dynamics of electrone wave packet tunneling through a potential barrier in a MOS (metal-oxide-semiconductor) diode was performed by solving the time-dependent Schrödinger equation using the finite difference method. The wave packet is initially located in the semiconductor layer then moves toward to the oxide layer and probably tunnels through and/or is reflected by the oxide layer. The wave packet is deformed when it reaches the oxide layer. It is found that the higher the wave packet energy, the faster the wave packet moves and the higher the probability of transmitting the wave packet for the same bias voltage. It was also found that at low energy, the increase of bias voltage does not increase significantly the probability of finding the transmitted wave packet. At high energy, however, the probability of finding the transmitted wave packet becomes higher with increasing the bias voltage.
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.
Percolation Model for Proton Immobility in Ice Abdullah, Mikrajuddin
Journal of Engineering and Technological Sciences Vol 37, No 1 (2005)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (241.717 KB) | DOI: 10.5614/itbj.eng.sci.2005.37.1.5

Abstract

A simple Ising model and a statistical theory of gel formation in a polymer matrix were combined to explain the effect of temperature on the mobility of protons in ice. Cowin et al observed that protons in ice bulk were immobile at temperatures below 190 K, and suddenly become mobile at temperatures above 190 K [Nature 398, 405 (1999)]. We proposed here that the transport of protons is controlled by a percolation mechanism. The proton transport is facilitated by the occurrence of easily reoriented water molecules in the ice bulk. The fraction of this molecule depends on temperature and was calculated using a simple Ising model. The formation of network of these molecules which provides pathways for proton transport was calculated using a statistical theory of gel formation in a polymeric system. Our model succeeded to reproduce the variation of potential difference between the ice film surfaces with respect to temperature as observed by Cowin et al based on a soft landing experiment.
Zinc Oxide Nanoparticles Prepared By a Simple Heating: Effect of Polymer Addition and Polymer Absence on the Morphology Abdullah, Mikrajuddin; Okuyama, Kikuo
Journal of Engineering and Technological Sciences Vol 36, No 2 (2004)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1682.156 KB) | DOI: 10.5614/10.5614/itbj.eng.sci.2004.36.2.5

Abstract

Zinc oxide (ZnO) nanoparticles were prepared by a simple heating of precursors in a furnace at temperatures of below 1000°C in an air environment. If zinc nitrate was used as precursor, polymer (e.g., polyethylene glycol (PEG)) must be added into the precursor to produce ZnO in nanometer size. The absence of polymer led to the presence of several micrometer-sized flakes. In addition, the heating temperatures must be higher than 500°C to completely decompose the organic material in final product. However, if zinc acetate was used as precursor, nanometer-sized ZnO having a high crystallinity can be obtained even when the polymer was absent. Interestingly, we also found that heating at low temperatures (e.g. 400°C) resulted in ZnO nanorods with an elongation ratio of around 5. This method is rapid, economically efficient, and readily scalable for industrial applications.
Fabrication of Microporous Water Filter Using Titanium Dioxide Particles, Silica Particles, and Polyethylene Glycol Priatama, Aris; Abdullah, Mikrajuddin; Khairurrijal, Khairurrijal; Mahfudz, Hernawan
Journal of Engineering and Technological Sciences Vol 42, No 1 (2010)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (561.473 KB) | DOI: 10.5614/itbj.eng.sci.2010.42.1.3

Abstract

We report the fabrication of microporous filter for use in filtering both inorganic  and  organic  substances  from  liquid  materials.  Titania  (TiO 2)  anatase was  used  as  the  main  material  for  this  filter.  Polyethylene  glycol  (PEG)  with average  molecular  weight  of  20,000  was  also  used  as  additive  to  control  the formation  of  pores,  especially  pore  sizes.  The  mixture  of  titania  and  PEG  was pressed into cylindrical tablet shape at room temperature  and then simply heated inside a furnace up to temperature where the PEG decomposed into gas to leave only connected titania particles. The use of titania as base material for the filter allows  the  organic  substances  that  trapped  inside  the  filter  pores  to  be  easily removed by heating up the used filter at above decomposition temperature of the trapped  organics.  We  also  made  other  filter  by  adding  small  amount  of  silica (SiO2)  particles  to  reduce  the  size  of  the  pores  as  well  as  to  improve  the mechanical  strength.  We  observed  that  filters  containing  silica  particles,  with smaller  in  size  compared  to  titania,  resulted  in  better  mechanical  strength, smaller in pore sizes and better filtering results in term of turbidity and dissolved oxygen (DO) content. This  method is potential for development of larger scale and cheaper water filters for use in various applications.
Co-Authors - Masturi A. Suhendi A.A. Ketut Agung Cahyawan W Agus Subagio Amalia, Nadya Andhy Setiawan Anrokhi, Mohamad Samsul Arif Surachman Aris Priatama Asri, Asifa Aufa Maulida Fitrianingrum Bebeh Wahid Nuryadin Edy Supriyanto Edy Wibowo Endah Rahmawati Endah Rahmawati Euis Sustini Fatimah A. Noor Fatimah Arofiati Noor Ferry Iskandar Ferry Iskandar Ferry Iskandar Goib Wiranto Hasniah Aliah, Hasniah Hernawan Mahfudz Hery Sutanto Hwa, Lee Myong Ida Sriyanti Khairurrijal Khairurrijal Khairurrijal Khairurrijal Khairurrijal khairurrijal Khairurrijal Khairurrijal Khairurrijal, Khairurrijal Kikuo Okuyama Maharati Hamida Maman Budiman Maman Budiman Maman Budiman Mamat Rokhmat, Mamat Mohamad Barmawi Munir, Rahmawati Nadya Amalia Pepen Arifin Rahman, Dui Yanto Rahmawati, Rahmawati Rahmayanti, Handika Dany Riska Ekawita Riska Ekawita Rokhmat, Mamat S Saehana Septia Mahen, Ea Cahya Septianto, Ricky Dwi Sparisoma Viridi Sukirno Sukirno Sutisna, S. Ulya, Naily