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Moehamad Barmawi
Kelompok Keilmuan Fisika Material Elektronik, Program Studi Fisika Institut Teknologi Bandung, Bandung
Mathematics

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Penumbuhan Film Tipis Ti1-xCoxO2 Dengan Metode MOCVD Horasdia Saragih; Mersi Kurniati; Akhiruddin Maddu; Pepen Arifin; Moehamad Barmawi
Jurnal Matematika & Sains Vol 9, No 3 (2004)
Publisher : Institut Teknologi Bandung

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The Ti1-xCoxO2 thin films have been successfully deposited on Silicon (Si) substrates by metalorganic chemical vapor deposition (MOCVD). The Ti1-xCoxO2 thin films with x = 0 is grown at deposition temperature of 450oC with argon and oxygen flow rate of 100 sccm and 60 sccm, respectively. The deposited film has a single orientation of (213)-anatase. The films consist of nanometer size of columnar grains. The growth rate was increased with increasing Co content and therefore the grains become larger. Generally, the crystal structure of films was affected by Co atom concentrations, however at temperature deposition of 450oC and argon flow rate of 70 sccm, the film has the initial structure of (213)-anatase and co-exist with (301)-anatase which is not dominant. The film thickness is about of 0,9 μm for an area of 3x3 cm2.
Pengaruh Temperatur Penumbuhan Terhadap Karakteristik Magnetik Film Tipis TiO2:Co yang ditumbuhkan dengan Metode Metalorganic Chemical Vapor Deposition (MOCVD) Horasdia Saragih; Pepen Arifin; Moehamad Barmawi; Mersi Kurniati
Jurnal Matematika & Sains Vol 9, No 4 (2004)
Publisher : Institut Teknologi Bandung

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TiO2:Co thin films have been grown on p-type Si(100) substrates by MOCVD method. The films were grown at substrate temperature of 450 oC to 500 oC , and the temperature of precursor bubbler was kept constant at 50 oC with vapor pressure of 260 Torr. Flow rate of O2 and Ar are 60 sccm and 100 sccm, respectively. The crystal structure, grain shape and magnetic properties of the films depend significantly on the substrate temperature. The anatase-213 structure with columnar grain was formed for the films grown at temperatures of 400 oC and 450 oC. The arrangement of atoms at grain boundary is improved at growth temperature of 450 oC. Anatase-301 structure with cone grain shape as additional component appears at growth temperature of 500 oC. The TiCoO3 phase with 310 plane was found at growth temperature of 550 oC. The grains grow at direction of -45o from normal substrate. Films that grown at 450 oCand 500 oC exhibit soft magnetic properties with Hc of 100 Oe and 80 Oe; and Mr of 250 emu/cm3 and 220 emu/cm3, respectively. The hard magnetic properties of the films are shown for the films grown at 550 oC. The films were grown for 2 hours producing the films with thickness of about 0.7 to 0.9 μm.
Pengaruh Bentuk dan Fluktuasi Ukuran Dot terhadap Pelebaran Garis Spektral Inhomogen pada Quantum Dot Gallium Nitrida (QD GaN) Fitri Suryani Arsyad; Budi Mulyanti; Amiruddin Supu; Moehamad Barmawi
Jurnal Matematika & Sains Vol 12, No 4 (2007)
Publisher : Institut Teknologi Bandung

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Theoretical analysis of the phenomena of the size fluctuation in Gallium Nitride quantum dot (GaN QD) is presented inthis paper. The effect of QD size fluctuation on the electron and hole energy level and the inhomogeneous linebroadening is studied. Analytical expressions for the inhomogeneous line broadening are derived for a Gaussian sizefluctuation distribution. Decreasing in the QD carrier energy level is observed when QD size increases. The peak ofoptical transition energy probability (Emax) is shifted to higher energy when dot size fluctuation (σL) increases. Theoptical transition energy distribution (fE) of cylindrical QD is at the higher energy with the inhomogeneous linebroadening (σE) wider than those of conical, ellipsoidal, as well as semi ellipsoidal QD.
Co-Authors Akhiruddin Maddu Amiruddin Supu Budi Mulyanti Fitri Suryani Arsyad Horasdia Saragih Mersi Kurniati Pepen Arifin