Ferry Iskandar
Departemen Fisika, Fakultas MIPA Institut Teknologi Bandung

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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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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
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%.
Pengaruh Penambahan SiO2 dan PTFE Terhadap Respon Termolumi-nesensi TLD CaSO4:Dy Nuraeni, Nunung; Kartikasari, Dewi; Iskandar, Ferry; Haryanto, Freddy; Waris, Abdul; Hiswara, Eri
Jurnal Matematika dan Sains Vol 22 No 1 (2017)
Publisher : Institut Teknologi Bandung

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Thermoluminescence response of TLD CaSO4: Dy with a variation of the addition of SiO2 and PTFE materials has been observed. TLD CaSO4:Dy derived through co-precipitation method and then added by SiO2 and PTFE. Thermoluminescence intensity for CaSO4:Dy added by SiO2 obtained 9.41, 5.32; and 13.93 nC for the temperature at 400 °C, 600 °C and 700 °C. As for CaSO4:Dy with the addition of PTFE obtained 33.10;  336.89; and 1191.11 nC for the temperature at 400 oC temperature, 600 °C and 700 °C. Thermoluminscence intensity for CaSO4:Dy without the addition of SiO2 and PTFE at a temperature of 700 °C is 75.15 nC. There’s a significant increasing in the thermoluminescence intensity on CaSO4:Dy added by PTFE.
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.
Simple Fabrication of Carbon Nanotubes from Ethanol using an Ultrasonic Spray Pyrolysis Abdullah, Mikrajuddin; Iskandar, Ferry; 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 (850.475 KB) | DOI: 10.5614/10.5614/itbj.eng.sci.2004.36.2.3

Abstract

Carbon nanotubes of diameter (20–100 nm) are synthesized by pyrolyzing a sprayed solution of Fe(C5H5)2 and C2H5OH in an Ar atmosphere at relatively low temperatures (around 800 oC). The tubular structures consist of highly crystalline nested graphene cylinders (<200 concentric tubes). Tube diameter can be controlled by varying the furnace temperature, carrier gas flow rate and the Fe:C ratio within the precursor solution. This low cost route for the synthesis of carbon nanotubes is advantageous due the low pyrolytic temperature, safety, processable in atmospheric pressure, and scalable.
Effect of Polystyrene Latex Addition on Size and Pore Volume of Porous Calcium Oxide Particles Prepared by Spray-Pyrolysis Method and Its Ability for SO2 Retention Septianto, Ricky Dwi; Iskandar, Ferry; Abdullah, Mikrajuddin; Khairurrijal, Khairurrijal; Hwa, Lee Myong
Journal of Engineering and Technological Sciences Vol 50, No 2 (2018)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3896.008 KB) | DOI: 10.5614/j.eng.technol.sci.2018.50.2.6

Abstract

In this study, the effects of polystyrene (PS) latex addition on the particle morphology and the pore content of calcium oxide (CaO) were investigated. The CaO particles were prepared using an ultrasonic nebulizer-assisted spray-pyrolysis method with variation of the PS/Ca(NO3)2·4H2O mass ratio in the precursor. Good crystallinity of CaO was obtained at 825°C of synthesis temperature under 2 l/min of nitrogen gas flow, which was confirmed by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). According to scanning electron microscope (SEM) characterization, the CaO particles synthesized with 0 and 25 wt% PS addition had an almost spherical shape with an average size of 1.58 and 1.48 µm, respectively. In addition, macropores were formed in the CaO particles prepared with 25 wt% PS addition that had an average pore diameter of 583.26 nm. Meanwhile, the CaO particles prepared with 75 wt% PS addition had a random shape and an average size of 1.41 µm. The mesopore content was investigated by Barret-Joyner-Halenda (BJH) analysis, which showed improvement of the pore size from 3.45 nm to 5.42 nm for 0 and 25 wt% PS addition, respectively, which is proportional to the pore volume, pore surface area, and the capacity of SO2 retention.
Electrochemically Exfoliated Graphite/Cu/Cu2O Composites and Their Photocatalytic Activity Destiarti, Lia; Abdillah, Oktaviardi Bityasmawan; Maharsi, Retno; Floweri, Octia; Iskandar, Ferry
POSITRON Vol 10, No 1 (2020): Vol. 10 No. 1 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v10i1.37260

Abstract

In this work, the photocatalytic performance of electrochemically exfoliated graphite (EG) with low copper addition (≤ 5 wt.%) was studied. Composites of EG/Cu/Cu2O were successfully prepared by microwave-assisted in situ reduction method. FTIR spectra of the samples showed that the main functional groups of graphite were detected in the samples. XRD characterization further proved the presence of EG, Cu, and Cu2O in the samples. The higher proportion of Cu2O presented in the samples prepared with a higher amount of Cu2+. SEM analysis showed that Cu2O/Cu particles were homogeneously deposited on the surface of EG. The composites of EG, Cu, and Cu2O with a varied amount of Cu (1 and 5 wt. %) in EG / Cu2+ mixture were examined as photocatalyst in the degradation process of Rhodamine B (RhB). The photocatalytic degradation of RhB was analysed by observing its decolorization within a set time of irradiation. UV-Vis analysis revealed that the degradation of RhB in EG/Cu/Cu2O A and B for 105 minutes was 26 and 35 %, respectively. The result demonstrates that the sample with a larger amount of Cu2O (sample B, Cu 5 wt.%) shows higher photocatalytic activity in the degradation of RhB.
Pengaruh Konsentrasi Sumber Karbon Terhadap Sifat PL Fosfor Boron Carbon Oxynitride(BCNO) Nina Yunia Hasanah; Bebeh Wahid Nuryadin; Ferry Iskandar
ALHAZEN Journal of Physics Vol 1, No 1 (2014)
Publisher : UIN Sunan Gunung Djati Bandung

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Kami berhasil mensintesis partikel fosfor BCNO dengan metode pemanasan sederhana menggunakan furnace. Kami menggunakan asam sitrat sebagai sumber karbon karena asam sitrat memiliki distribusi berat molekul yang seragam dan bersifat reaktif terhadap sumber boron dan sumber karbon. Variasi ntensitas pendaran dan puncak PL dapat diperoleh dengan memvariasikan konsentrasi sumber karbon dan temperatur sintesis. Temperatur sintesis yang kami gunakan yaitu 700oC, 750oC, 800oC, 850oC. Temperatur optimum untuk menghasilkan fosfor BCNO adalah pada temperatur 750oC. Partikel fosfor BCNO dikarakterisasi dengan menggunakan scanning electron microscope (SEM) dan PL spectra. SEM digunakan untuk melihat morfologi partikel fosfor BCNO sedangkan PL spectra digunakan untuk mengetahui intensitas pendaran dan puncak yang dihasilkan. Hasil karakterisasi dengan menggunakan scanning electron microscope (SEM) menunjukkan  bahwa morfologi fosfor BCNO berukuran mikron.