Pepen Arifin
Lab. Fisika Material Elektronik, Jurusan Fisika FMIPA - ITB

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Karakteristik Film Tipis GaAs yang Ditumbuhkan dengan Metode MOCVD Menggunakan Sumber Metalorganik TDMAAs (Trisdimethylaminoarsenic) Andi Suhandi; Heri Sutanto; Pepen Arifin; Maman Budiman; Mohamad Barmawi
Jurnal Matematika & Sains Vol 10, No 1 (2005)
Publisher : Institut Teknologi Bandung

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Gallium Arsenide (GaAs) film have been grown by Metalorganic Chemical Vapor Deposition (MOCVD) method on Semi Insulating-Gallium Arsenide (SI-GaAs) substrates using of Trisdimethylaminoarsenic (TDMAAs) and Trimethylgallium (TMGa) precursors. The characteristic of GaAs film strongly depends on growth temperature. The best crystallinity quality of film was obtained at growth temperature, V/III ratio, reactor pressure, N2 and H2 dilute are 580 oC, 4.8, 50 torr, 300 sccm, respectively. X-ray diffraction data indicate that the GaAs films grown at 580 oC show epitaxial layer with FWHM on (200) peak of about 0,477o. Hall effect measurement data indicate that the grown layer were p-type semiconductor, with Hall mobility and carrier concentration in the range of 346 cm2/V.s and 3.17 x 1017 cm-3, respectively. The band gap of GaAs films determined by photoluminiscense (PL) measurement was 1,42 eV. This value is same as the band gap of bulk GaAs.
Efek Magnetisasi Spontan dan Karakteristik Transport Listrik Film Tipis TiO2:Co yang ditumbuhkan dengan Metode MOCVD Horasdia Saragih; Pepen Arifin; Mohamad Barmawi
Jurnal Matematika & Sains Vol 10, No 1 (2005)
Publisher : Institut Teknologi Bandung

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TiO2:Co thin films were grown on Si(100) substrate by MOCVD method. The Co content in the film was varied in the range of 0.73% to 12.19%. The spontaneous magnetization effect and the electrical transport of films were measured by means of a Hall effect measurement. The Hall resistivity as a function of the magnetic field data show that the spontaneous magnetization effect occurs in films at the field lower than 1500 Oe. The Hall resistivity increases with the increase of Co concentration. The measurement of resistivity as function of temperature shows that the films have semiconductive properties. The minimum resistivity increases with increasing Co.
GaN-based Double-hetero Film Grown and Fabricated on (0001) Sapphire Substrates by Plasma-assisted MOCVD Heri Sutanto; Edi Supriyanto; Maman Budiman; Pepen Arifin; Sukirno Sukirno; Mohamad Barmawi
Jurnal Matematika & Sains Vol 10, No 2 (2005)
Publisher : Institut Teknologi Bandung

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GaN-based double-hetero film has been grown on (0001) sapphire substrate by plasma-assisted MOCVD method. The structure of film was n-GaN/Al0.25Ga0.75N/In0.3Ga0.7N/Al0.25Ga0.75N/p-GaN. A photoluminescence (PL) peak originating from InGaN active layer has been observed at room temperature, which produced emission wavelength of 453 nm corresponded to energy of 2.74 eV. However, broadening of the peak caused by the crystalline quality of the InGaN epilayer is still poor, which is related with fluctuation of In rich regions.
Anisotropi Magnetik Film Tipis TiO2:Co yang Ditumbuhkan dengan Teknik MOCVD Horasdia Saragih; Pepen Arifin; Mohamad Barmawi
Jurnal Matematika & Sains Vol 10, No 4 (2005)
Publisher : Institut Teknologi Bandung

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TiO2:Co thin films have been successfully deposited by using MOCVD technique. The titanium (IV) isopropoxide [Ti(OCH(CH3)2)4] 99,99%, tris (2,2,6,6-tetramethyl-3, 5-heptanedionato) cobalt (III) 99%, and oxygen gas (O2) were used as Ti, Co, and O precursors, respectively. Crystal structure, morphology and magnetic properties of thin films were investigated by X-ray diffractometer (XRD), scanning electron microscope (SEM), and vibrating sample magnetometer (VSM), respectively. The magnetic anisotropy (K) of thin films was very strong depended on the growth temperatures. The thin film grown at temperature of 400°C has anatase-213 structure and K value of 40000 Oe.emu/cm3. At the growth temperature of 450°C, the thin films were has still anatase-213 and K value of 95000 Oe.emu/cm3. At growth temperature of 500°C, the thin films have K value of 72000 Oe.emu/cm3. The crystal structure of films was changed with an additional plane of anatase-301. The thin film grown at temperature of 550°C has K value of 103600 Oe.emu/cm3. The structure of thin film was polycrystalline, mixed by anatase-213, rutile-220 and TiCoO3 (310) phase. All of films have thickness of about 0,7-0,9 µm.
Karakteristik Struktur dan Listrik Film Tipis GaN yang Ditumbuhkan di atas Substrat Si(111) dengan Metode Plasma Assisted-Metalorganic Chemical Vapor Deposition (PA-MOCVD) Heri Sutanto; Agus Subagio; Edi Supriyanto; Pepen Arifin; Sukirno Sukirno; Maman Budiman; Mohamad Barmawi
Jurnal Matematika & Sains Vol 11, No 1 (2006)
Publisher : Institut Teknologi Bandung

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Gallium nitride (GaN) thin films have been grown on Si(111) substrate by PA-MOCVD method, with trimethylgallium (TMGa) and radical nitrogen resulted by plasma of nitrogen gas as a source of Ga and N respectively. The growth was performed at 675 °C; 0.4 torr; 90 sccm and 0.08-0.12 sccm of substrate temperature, reactor pressure, gas flow of nitrogen and TMGa, respectively. The grown polycrystalline GaN thin films have hexagonal structure and n-type semiconductor. The growth rate of the grown thin films increased with increasing gas flow of TMGa. The Hall mobility value of films is still low due to the presence of O and C impurities. The highest value of mobility was found to be 64.88 cm2/V.s with 5.47 x 1018 cm-3 of carrier concentration.
N-Type Conductivity in Wurtzite Mn-Doped GaN thin Films Grown by Plasma Assisted MOCVD Budi Mulyanti; Agus Subagio; Edi Supriyanto; Heri Sutanto; Fitri Suryani Arsyad; Pepen Arifin; Maman Budiman; Mohamad Barmawi
Jurnal Matematika & Sains Vol 11, No 2 (2006)
Publisher : Institut Teknologi Bandung

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Ferromagnetic semiconductor GaN:Mn thin films were successfully grown by plasma-assisted metalorganic chemical vapor deposition (PA-MOCVD) method on c-plane sapphire substrate. The films were grown at various Mn source flux in the range of 5 - 40 sccm and growth temperature which was lower than that of MOCVD themal, i.e. in the range of 625-700 °C. Cyclopentadienyl manganese tricarbonyl (CpMnT) was used as a source of Mn. X-ray diffraction patterns confirmed that GaN:Mn films are wurtzite and do not show second phase for film with Mn concentration up to 6.4% at 650 °C of growth temperature. Hall effect measurements show n-type characteristics. The carrier (electron) density tends to decreases and Hall mobility tends to with the increase of Mn concentration is increased. Hysteresis curves observed from VSM measurements indicated that all of the samples are ferromagnetic at room temperature.
Magnetoresistansi Divais Spintronika TiO2:Co/Si/TiO2:Co [Spintronics Magnetoresistance Device with TiO2:Co/Si/TiO2:Co] Edy Supriyanto; Agus Subagio; Hery Sutanto; Horasdia Saragih; Maman Budiman; Pepen Arifin; Sukirno Sukirno; Mohamad Barmawi
Jurnal Matematika & Sains Vol 12, No 1 (2007)
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TiO2:Co thin films were grown on Si substrates by Metalorganic Chemical Vapor Deposition (MOCVD) technique using titanium(IV)isopropoxide and tris(2,2,6,6-tetramethyl-3,5-heptanedionato)cobalt (III), and oxygen gas. The films grown at temperature of 450 oC were crystalline having a rutile structure with (002) orientation. Based on Energy Dispersive Spectroscope (EDS) analysis, Co content in TiO2 was 1.83% and films exhibit ferromagnetic properties at room temperature. Hysteresis curves obtained from Vibrating Sample Magnetometer (VSM) measurement have coercive and saturation magnetic fields of 130 Oe and 2.1 emu/cm3, respectively. Application of TiO2:Co as injection material in spintronic device with TiO2:Co/Si/TiO2:Co structure was investigated. The effect of polarized spin injection (magnetoresistance phenomenon) was observed from the current-voltage characteristics of the device.
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.
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.