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Mikrostruktur Semikonduktor GaN di Atas Substrat Silikon Dengan Metode Sol-Gel

BERKALA FISIKA Vol 13, No 2 (2010): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Gallium nitride (GaN) semiconductor thin films have been successfully deposited on Si substrate (004) by sol-gel method. Gel prepared from the crystal gallium-citrate-amines. These crystals formed from a solution containing the ions Ga+3 and citric acid (CA). Gel in place on the substrate and then rotated with a speed of 1100 rpm. The gel layers are obtained and then placed on the programmable furnace. Deposition temperature varied of 800, 900 and 1000oC in a nitrogen gas environment during 2 hour. The crystal quality of GaN thin films have characterized by XRD measurement. The surface morphology and cross section of the films observed by SEM. The film compositions determined by EDX characterization. The results showed that all the GaN thin films on silicon substrate have oriented polycrystalline structure. The crystal quality of GaN film is formed is influenced by the deposition temperature. In a deposition temperature range is used, increasing the deposition temperature can improve the crystal quality of GaN films.   Keywords: GaN Thin Films; Spin-Coating Technique; Silicon Substrate

Pengaruh Laju Molar Mn Larutan Terhadap Mikrostruktur Lapisan Tipis GaN:Mn yang Dideposisi di atas Substrat Si Menggunakan Metode Sol-Gel

BERKALA FISIKA Vol 14, No 2 (2011): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

A thin layer of material deposition of GaN: Mn by sol-gel method has done using spin-coating technique. Solution of gallium-citrate-amine maganese-Ga2O3 synthesized using as a source of Ga and Mn MnO2 as the source. Solution varied with the mole fraction solution of 60-80% Mn. Brown crystals that formed subsequently dissolved in ethylenediamine to form a gel. Subsequent gel superimposed on top of Si substrates with a spin-coater at a rate of 1100 rpm. Layers formed at temperatures of 900oC and then disintering in UHP N 2 gas environment to form the decomposition of GaN: Mn. The results of spectral analysis of energy dispersive X-ray (EDX) showed incorporation of Mn into the GaN mole fraction increased with the addition of a solution of Mn in the solution used. EDX Test results show that thin films of GaN: Mn impurity contained carbon (C) up to 36.71%. Image scanning electron microscopy (SEM) a thin layer of GaN: Mn shows in general have been obtained surface roughness (rms) morphology of the layer reaches the order of nanometers up to 24.36 nm. From the results already obtained show that the sol-gel deposition method has been able to produce a thin layer of magnetic semiconductors with a nearly homogeneous surface morphology. Thus the sol-gel method could be developed for alternative methods of deposition of thin layers that are economical and simple. Key words: GaN: Mn, CSD, Thin Layer, Mn incorporation.

ANALISIS MIKROSTRUKTUR NANOPARTIKEL CeO2 DIDOPING Zn YANG DISINTESIS MENGGUNAKAN METODE PRESIPITASI

YOUNGSTER PHYSICS JOURNAL Vol 2, No 2 (2013): Youngster Physics Journal April 2013
Publisher : YOUNGSTER PHYSICS JOURNAL

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Abstract

Zn-doped CeO2 nanoparticles with various Zn content of 0 - 20% have been synthesized by using precipitation method in the solvent mixture of aquades and isopropanol at room temperature.  The precipitant was calcinated at temperatur 300oC for 3 hours.  The structural properties of CeO2 nanoparticles were characterized by using x-ray diffraction.  X-ray diffraction pattern was analyzed to investigate the influence of Zn doping on crystalite size, lattice constant and lattice strain of CeO2 nanoparticle.  Observation to the peaks diffraction indicate that all of the CeO2 nanoparticle with various Zn doping have cubic fluorite structure and lattice constants in the range 5,4155 Å – 5,4254 Å.  The crystallite sizes of 6 – 11 nm were obtained by Williamson-Hall plot method.  Incorporation of Zn to the CeO2 nanoparticle decrease the crystallite size.  The crystallite size of Zn-doped CeO2 nanoparticles is depend on Zn%. Keywords: CeO2, nanoparticle, precipitation, lattice constant, x-ray diffraction

STRUKTUR NANOKRISTAL CeO YANG DISINTESIS MENGGUNAKAN METODE PRESIPITASI DENGAN VARIASI LAMA WAKTU KALSINASI 2

BERKALA FISIKA Vol 14, No 4 (2011): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Nanocrystalline CeO have been synthesized by using a precipitation method. in a mixedsolvent system of aqua DM and isopropanol. Precipited was calcined at temperature of 300 C forvarious calcination time.  X-ray difractometer was used to investigate resulting presipitedmicrostructure.  X-ray diffraction patterns were analyzed to study effect of calcination time tostructure and crystallite size. Refinement process of x-ray diffraction pattern was carried out byusing Rietveld method.  The results show that all of precipited were CeO  nanocrystalline withsingle phase of cubic fluorite.  The difference in lattice parameter was correlated to oxygenvacancy.  Crystallite size was found in the range 9 – 11 nm, its incresed as calcination timeincreased.   The increasing of calcination time did not significant influence to  crystallite size. These result indicated that CeO  nanocrystalline  exhibited weak-agglomeration.Keywords: CeO222, nanocrystalline, microstructure, x-ray diffraction, precipitation 2o

Sintesis Nanopartikel Cerium Oxide Menggunakan Metode Presipitasi dan Sifat Optiknya

BERKALA FISIKA Vol 15, No 2 (2012): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Cerium oxide nanoparticles have been synthesized using precipitation method in mixed-solvent system of aquades DM and isopropanol with volume rasio of 1:6.  Presipitation wascarried out by dropping amonium hidroxide to cerium nitrate hexahydrate solution until pH of 9. Precipitated was dried at temperature of 60oC for 2 hours and then calcined  for 2 hours attemperatur of 200oC, 300o and 400oC. Optical properties of cerium oxide nanoparticles werecharacterized using UV-Vis spectrophotometer. Cerium oxide nanoparticles exhibit goodtransparency in visible region and strong UV absorbance. These reults suggesting that ceriumoxide nanoparticles are potential as bionanomaterial for application in UV-blocker.Keywords: cerium oxide, nanoparticles, precipitation, UV filter, band gap energy, UV-Visspectrophotometer

EVALUASI PERUBAHAN STRUKTUR AKIBAT SUBSTITUSI PARSIAL ION Mn +2 DAN ION Ti PADA M HEKSAFERIT BaFe 12-2X Mn MENGGUNAKAN ANALISIS RIETVELD

BERKALA FISIKA Vol 14, No 3 (2011): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Cationic interaction of Mn+2and Ti +4substitution on conventional hexaferriteBaFe O have been studied using X-ray diffraction (XRD) and  analysis by the Rietveld method. These Research was conducted by combining compound of Fe O12 19 TiO2 to form  (Fe,MnTi)2O  phase3BaCO3 phase and heated at 1200. Then, Compound of (Fe,MnTi)0 C to form of BaFe12-2xresult of rietveld analysisshowed that the composition of Hexaferrite BaFe22 3, MnCO  and3O  phase mixed withMn Ti O3x x 19 compounds. The  as main phase and Fe2Oas a second phase. At all compositions showed that the largerfraction of ions Mn+23  and Ti+4 ions able to change latice parameter from  the volume unitcell of conventional hexaferrite. The results reatveld iteration of the phaseBaFe MnTiO (x = 1.0) obtained values of lattice parameters a = 5.9116 Ǻ and c =23.2532 Ǻ or shrinkage abaut 5,0 % volume unit cell and at  BaFe Mn Ti O10 19 (x=2.5)the volume unit cell 7,0% lower  than conventional hexaferrite.Keywords: Rietveld, unit cell, substitusi io,  hexaferrite, 12-2x7 2.5 2.5 19Mn Ti Ox x 19

Effect of Milling Time on nanostructured Hydroxyapatite Results Synthesis by Precipitation Method

Chem Info Journal Vol 1, No 2 (2013)
Publisher : Chem Info Journal

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Abstract

A study "Effect of Milling Time on Nanostructured Hydroxyapatite Synthesis Results by Precipitation Method" in purpose to know the effect of milling time on purity, phases and size of hydroxyapatite crystals synthesized. Hydroxyapatite (HA) were synthesized by the method of precipitation by adding dropwise a solution of CaCl2 to a solution of KH2PO 4 which has been conditioned at pH 9 with stirring and heated at 40 °C for 4 hours. The resulting suspension was allowed to stand for 20 hours. Product of precipitation milled using a Planetary Ball Mill at 880 rpm angular velocity and the ratio of powder/ballmill 1:10 with milling time variation 0, 5, 15, 30 and 60 minutes. Based on the FTIR and XRD, it was concluded that the HA produced by milling time of 60 minutes has not been able to achieve high purity. Another type of calcium phosphate formed on the product is calcium hydrogen phosphate anhydrous (CHPA). The longer the milling time, the smaller the size of HA crystals. Size of HA crystals are formed on the nanometer scale is 49.85 nm; 38.30 nm; 34.84 nm; 33.44 nm and 30.44 nm.

PENGARUH LAJU MOLAR Mn LARUTAN TERHADAP MIKROSTRUKTUR FILM LAPISAN GaN: Mn YANG DIDEPOSISI DI ATAS SUBSTRAT Si MENGGUNAKAN METODE CSD

Prosiding Seminar Nasional Sains Dan Teknologi Fakultas Teknik Vol 1, No 1 (2011): PROSIDING SEMINAR NASIONAL SAINS DAN TEKNOLOGI 2 2011
Publisher : Prosiding Seminar Nasional Sains Dan Teknologi Fakultas Teknik

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Abstract

Abstrak Telah dilakukan deposisi lapisan tipis material GaN:Mn dengan metode chemical solution deposition (CSD) menggunakan teknik spin-coating. Larutan gallium-maganese-citrate-amine disintesis menggunakan Ga2O3 sebagai sumber galium dan MnO2 sebagai sumber mangan. Larutan divariasi dengan fraksi mol larutan Mn dari 55-80%. Kristal berwarna coklat  yang terbentuk selanjutnya dilarutkan dalam ethylenediamine membentuk gel. Gel selanjutnya dilapiskan di atas substrat Si dengan spin-coater pada laju 1100 rpm. Lapisan yang terbentuk kemudian disintering pada temperatur 900oC pada lingkungan gas N2 UHP supaya terjadi dekomposisi membentuk GaN:Mn. Hasil analisis spektrum energy dispersive of X-Ray (EDX) menunjukkan inkorporasi Mn ke dalam GaN meningkat dengan penambahan fraksi mol larutan Mn pada larutan yang digunakan. Hasil Uji EDX menunjukkan bahwa film tipis GaN:Mn terdapa impuritas karbon (C) hingga 36,71%. Citra scanning electron microscopy (SEM) lapisan tipis GaN:Mn menunjukkan secara umum telah diperoleh kekasaran permukaan (rms) morfologi lapisan mencapai orde nanometer hingga 24,36 nm. Dari hasil yang telah diperoleh menunjukkan bahwa metode deposisi CSD telah mampu menghasilkan lapisan tipis semikonduktor magnetik dengan morfologi permukaan yang hampir homogen. Dengan demikian metode CSD ini dapat dikembangkan untuk metode alternatif deposisi lapisan tipis yang ekonomis dan sederhana. Kata kunci: GaN:Mn, CSD, Lapisan Tipis, Inkorporasi Mn

STUDI PENGAPLIKASIAN EFEK FOTOKATALIS DARI LAPISAN ZnO:Ag TERHADAP DEGRADASI BAKTERI E.coli

YOUNGSTER PHYSICS JOURNAL Vol 4, No 3 (2015): Youngster Physics Journal Juli 2015
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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Abstract

Research in the field of green technology using photocatalyst materials can be a solution to environmental pollution, especially contamination of aquatic bacteria. These materials absorb energy from the sun and form hydroxyl radicals that kill bacteria. Zinc oxide has a high photocatalytic efficiency with Eg 3.3 eV in the range of UV - visible light. ZnO can be modified by addition of silver in order to improve the effectiveness as well as anti-bacterial properties. ZnO:Ag 4% layers prepared with thermal spray coating method with deposition temperature at 250ºC and aneling temperature at 450 ºC. XRD measurements performed with CuKα radiation with wavelength at 1.54060 Å and the diffraction angle in range 20 ° - 70 °. The diffraction patterns were identified using the Crystallography Open Database (COD) and software QUALX. ZnO (Id 101-1259) phase and metal Ag (Id 151-2487) phase has formed, but there are also silver oxide phase AgO (Id 150-9488) and Ag2O (Id 150-9684). Crystallite size has been calculated using Debye-Scherrer equation resulted an average value 43.46 nm. The optical properties were measured using a UV-Vis spectrometer in the wavelength range 250-800 nm. Transmittance spectrum were converted into an absorbance spectrum using the Beer-Lambert law. Eg value were analyzed with methods taucs plot. Linear extrapolation (αhν)2 against hν provide direct transition Eg value 3.1 eV. Photodegradation ability of ZnO:Ag layer performed on E.coli bacteria. TPC measurement results were analyzed using the degradation rate graph, Ct (bacteria concentration) against time exposure. The degradation rate values obtained 1.554 x 10-17 (cfu/ml)-2(minutes)-1.Keywords : ZnO:Ag, band gap energy, XRD, Uv-Vis, TPC, degradation rate.

DEPOSISI LAPISAN TIPIS FOTO KATALIS SENG OKSIDA (ZnO) BERUKURAN NANO DENGAN TEKNIK PENYEMPROTAN DAN APLIKASINYA UNTUK PENDEGRADASI PEWARNA METHYLENE BLUE

Jurnal Fisika Vol 3, No 1 (2013)
Publisher : Jurnal Fisika

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Abstract

Material seng oksida (ZnO) adalah salah satu semikonduktor oksida dengan celah pita energi 3,2 eV yang bersifat fotokatalis dapat digunakan untuk mendegradasi polutan berwarna seperti metylene blue (MB). Pada penelitian ini telah berhasil dideposisi lapisan tipis ZnO di atas substrat kaca dengan metode sol-gel teknik penyemprotan/spray coating. Gel ZnO 0,5 M disintesis dengan melarutkan Zinc acetate dehydrate ke dalam larutan isopropanol dan monoethanolamine pada temperatur ruang dengan perbandingan molar dari MEA dan ZnAc yaitu 1:1. Kemudian larutan diaduk menggunakan pengaduk magnetik pada temperatur 70oC selama 30 menit hingga didapatkan gel ZnO yang jernih dan homogen. Gel ZnO diletakkan pada spray hole dan disemprotkan pada substrat kaca yang telah dipanasi sampai temperatur 250oC. Lapisan hasil penyemprotan selanjutnya di sintering pada temperatur 400oC selama 1 jam. Hasil deposisi lapisan ZnO bersifat transparan dengan nilai transmitansi sebesar 71,4% dan semakin menurun dengan penurunan panjang gelombang yang dikenakan pada lapisan. Hasil pengujian komposisi dengan energy dispersive of X-Ray (EDX) menunjukkan bahwa komposisi seng (Zn) lebih sedikit daripada oksigen (O) dengan perbandingan Zn:O = 46,13% : 53,87%. Hasil uji citra Scanning electron microscopy (SEM) menunjukkan lapisan tipis ZnO mempunyai permukaan yang halus dan homogen dengan ukuran grain sebesar 57 nm dan ketebalan lapisan sebesar 204 nm. Hasil uji ultra violet visibel (UV Vis) spectrophotometer diperoleh nilai celah pita energi ZnO sebesar 3,01 eV. Dari informasi celah pita energi lapisan ZnO ini digunakan untuk aplikasi pendegradasi pewarna MB 100 ppm. Hasil uji aktifitas fotokatalis menunjukkan bahwa lapisan tipis ZnO telah mampu mendegradasi MB 100 ppm hingga 96,5% (menjadi bening) selama 6 jam dibawah iradiasi sinar matahari.