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"Silicon Carbide (SiC), juga dikenal sebagai carborundum merupakan komposisi kimia dari silikon dan karbon dengan formulasi kimianya adalah SiC. Terdapat di alam pada mineral langka mossanite. Butiran dari silikon karbida dapat mengikat dengan baik mengunakan metode sintering untuk menghasilkan keramik yang sangat keras, yang digunakan secara luas untuk penggunaan yang memerlukan tingkat ketahanan yang tinggi. Dalam penelitian tugas akhir ini, paduan SnPbSiC dibuat dengan menggunakan metode peleburan yang dilakukan pada udara terbuka. Variasi sampel paduan yang dibuat dengan persen berat SiC sebesar 4.26%, 7.41% dan 10.40%.Dari hasil karakterisasi XRD menunjukkan pengaruh penambahan SiC terhadap parameter kisi dan crystallite size dari SnPb. Karakterisasi termal dari semua variasi paduan SnPbSiC yang didapatkan menggunakan DSC menunjukkan penurunan dan kenaikan titik lebur paduan SnPb akibat penambahan SiC. SiC dengan Persen berat 10.40% membuat titik leleh menjadi turun dan untuk SiC dengan persen berat 4.26% dan 7.41% membuat titik leleh naik. Pengaruh penambahan SiC juga terlihat pada sifat kekerasan dari semua variasi paduan SnPbSiC dengan menggunakan vickers hardness test yaitu kekerasan paduan meningkat seiring SiC yang bertambah pada paduan SnPb.

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Silicon Carbide (SiC), also known as carborundum is chemical composition of silicon and carbon with the chemical formulation is SiC. There is a rare mineral in nature on mossanite. Grains of silicon carbide can bind well to the sintering method, produces a very hard ceramic, which is widely used for the use of which requires a high level of resilience. In this thesis, SnPbSiC alloys made using fusion methods are conducted in open air. Variation of alloy samples made with SiC weight percent for 4.26%, 7:41% and 10:40%.From XRD characterization results showed the effect of adding SiC to The lattice parameters and crystallite size of SnPb. Thermal Characterization of all variations SnPbSiC alloys obtained using the DSC showed decrease and increase the melting point of SnPb alloys due to the addition of SiC. SiC Percent of 10.40% by weight makes the melting point to decrease and for Weight percent SiC with 4.26% and 7.41% resulted in increased melting point . Ussing Vickers Hardness test, Effect of addition of SiC also looks at the properties of hardness of all SnPbSiC alloy variation increases the hardness of SiC increases in SnPb alloys."

"ABSTRAKUntuk mengurangi cacat pada kristal tunggal silicon dengan orientasi (100) yang telah ditumbuhkan dengan Metode Czochralski, telah dilakukan penganilan terhadap wafer-wafer kristal dengan variasi temperatur 1000, 1100 dan 1200 °C, serta waktu anil 6, 12 dan 24 jam. Metode yang digunakan dalam pengamatan cacat kristai adalah Metode Permukaan (etch pits) dengan luas efektif setiap titik pengamatan sebesar 0,11 mm2. Hasil pengamalan memperlihatkan terjadinya fluktuasi kuantitas cacat kristal dari ujung seed sampai ujung ingot: sampel tanpa proses anil mempunyai cacat yang berfluktuasi antara 4758 sampai 11495/cm2, sedangkan sampel yang dianil mempunyai cacat antara 1541 sampai 5388/cm2.

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ABSTRACT

In reducing the crystal defects at single crystal silicon with the orientation (100) which has been grown using Czochralski Method, the annealing process of crystal wafers have been done with temperature variation of 1000, 1100 and 1200 °C and also annealing time 6, 12 and 24 hours. Etch pits method has been used to obtain the crystal defects using an effective observation area of 0.11 mm2. The result shows that the defects fluctuation occur accross the length of the sample, from the seed-end toward the bottom-end, also the samples that were not annealed having the variation of crystal defects between 4758 to 114951cm2, while the samples that were annealed showing the defects variation between 1541 to 5388/cm2."

"Penelitian ini bertujuan untuk mengkaji efisiensi ekstraksi silika dari abu terbang (fly ash) PLTU menggunakan metode Sequential Acid-Alkaline Leaching (SAAL). Metode ini terdiri dari tiga tahapan utama: pelindian asam dengan HCl, pelindian basa dengan NaOH, dan presipitasi menggunakan H2SO4. Fly ash yang digunakan berasal dari limbah PLTU dengan kandungan silika yang tinggi. Fokus penelitian ini adalah pengaruh variasi konsentrasi NaOH dan H2SO4 terhadap recovery silika.Pada tahap pertama, pelindian asam menggunakan HCl dilakukan untuk menghilangkan pengotor seperti Fe, Ca, dan Al. Residu yang diperoleh kemudian dilindi dengan NaOH pada konsentrasi yang bervariasi untuk mengekstraksi silika sebagai natrium silikat. Filtrat yang mengandung natrium silikat selanjutnya dipresipitasi menggunakan H2SO4 untuk menghasilkan endapan silika. Hasil penelitian menunjukkan bahwa variasi konsentrasi NaOH dan H2SO4 memberikan pengaruh signifikan terhadap efisiensi ekstraksi silika. Konsentrasi NaOH yang lebih tinggi meningkatkan jumlah silika yang terlarut dalam larutan natrium silikat, sementara konsentrasi H2SO4 yang optimal diperlukan untuk menghasilkan presipitasi silika yang maksimal. Dengan metode ini, silika dengan kemurnian tinggi dapat diekstraksi dari fly ash, menunjukkan potensi pemanfaatan fly ash sebagai sumber silika yang bernilai tinggi.

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This study aims to evaluate the efficiency of silica extraction from coal fly ash using the Sequential Acid-Alkaline Leaching (SAAL) method. This method comprises three main stages: acid leaching with HCl, alkaline leaching with NaOH, and precipitation using H2SO4. The fly ash used in this study originates from a power plant waste with high silica content. The focus of this research is on the effect of varying concentrations of NaOH and H2SO4on silica recovery.

In the first stage, acid leaching with HCl is performed to remove impurities such as Fe, Ca, and Al. The resulting residue is then leached with NaOH at varying concentrations to extract silica as sodium silicate. The filtrate containing sodium silicate is subsequently precipitated using H2SO4 to produce silica precipitate. The results show that variations in NaOH and H2SO4 concentrations significantly affect the efficiency of silica extraction. Higher concentrations of NaOH increase the amount of silica dissolved in the sodium silicate solution, while an optimal concentration of H2SO4 is required to maximize silica precipitation. Using this method, high-purity silica can be extracted from fly ash, demonstrating the potential of fly ash as a valuable source of silica."

"Silika berpori disintesis melalui teknik co-Micelle/Emulsion Templatting (co-MET) dengan menggunakan template surfaktan kationik Cetyil Tetra Ammonium Bromide (CTAB). Silika yang digunakan berasal dari Tetra Etil Orto Silikat (TEOS) dengan variasi berat akrilamida sebesar 1,5 g ; 2 g ; 2,5 g ; 3 g ; 3,5 g dan tanpa poliakrilamida. Silika hasil sintesis dikarakterisasi menggunakan instrument FTIR, XRD, SEM-EDS, dan BET. Pada silika dengan berat akrilamida 2,5 gr ; 3 gr dan 3,5 gr terbentuk pori yang merata. Silika berpori dijadikan pendukung katalis AlCl3 melalui teknik impregnasi dan diuji optimasinya dengan reaksi esterifikasi asam asetat dan etanol yang dilihat dari luas daerah kromatogram GC-MS. Persen konversi yang didapat dari reaksi esterifikasi dengan menghasilkan etil asetat adalah 28,19% ; 49,99% dan 19,84% untuk penggunaan katalis dengan berat akrilamida 2,5 g; 3 g dan 3,5 g.

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Porous silica synthesized through co-Micelle/ Emulsion Templatting (co-MET) technique using template cationic surfactant Cetyil Tetra Ammonium Bromide (CTAB). Silica used from Tetra Ethyl Ortho Silicate (TEOS) with acrylamide weight variation of 1.5 g; 2 g; 2.5 g; 3 g; 3.5 g and without polyacrylamide. Silica synthesized were characterized using FTIR, XRD, SEM-EDS and BET. Silica produced with weight of acrylamide 2,5 g; 3 g and 3,5 g having pores diverse. Porous silica succesfully used as AlCl3 catalyst support by impregnation technique and tested optimization by esterification reaction of acetic acid with ethanol, which was analyzed using GC-MS. Percent conversion obtained from the esterification reaction is 28.19%; 49.99% and 19.84% for catalyst with weight of acrylamide 2.5 g; 3 g and 3.5 g."

"Perkembangan teknologi alat telekomunikasi dewasa ini begitu meningkat pesat. Salah satu faldor yang memungidnkan terciptanya aiat telekomunikasi tersebut adalah adanya sebuah transduser yang dapat mengubah suara menjacil slnyal listdk atau seballknya. Transduser yang dapat mengubah suara menjadi slnyal 11strIk dikenal dengan nama Mlkrolon. Jenis mikrofon yang ada cukup banyak. Yang paling banyak dlpakal adalah mikrofon yang menggunakan prinsip kapasltif yang lebih dikenal dengan nama mlkrofon kondenser. Pada Tugas Skdpsi Ini, dliakukan penelitian tentang rancangan mikrofon kondenser yang dibuat dengan menggunakan bahan sillkon yang berdimensi kecil serta menggunakan dlafragma yang menggunakan bahan sHikon nitdda dan berbentuk sinusoidal. Parameter-parameter yang dipakal pada struktur mlkrofon ini adalah panjang den tebai diafragma, lebar celah udara, tebal backpiate, dan banyaknya lubang akustik untuk mendapatkan sensltvitas dan tanggapan frekuensi mlkrofon tersebut. Penelltian dilakukan dengan penjabaran secara matematls dan menggunakan bantuan perangkat lunak. Dart hasli slmulasl dan perhitungan dldapatkan sensitNitas mikrofon sebesar 12 mV1Pa dan tanggapan frekuensl 13 kHz."

"Pembentukan produk oksidasi kolesterol pada proses pangan maupun kesehatan melibatkan reaksi kimia dan biokimia, reaksi oksidasi kolesterol ini dapat dikontrol melalui model kinetika pada tren oksidasi. Penggunaan model kinetika menjadi salah satu aspek penting dalam memprediksi kadar kolesterol hasil oksidasi. Reaksi oksidasi kolesterol melibatkan enzim sebagai katalisator, yaitu enzim kolesterol oksidase. Bakteri yang digunakan sebagai penghasil enzim kolesterol oksidase yaitu Streptomyces sp. Enzim kolesterol oksidase diproduksi dengan menggunakan metode fermentasi submerged. Untuk meningkatkan efektifitas enzim kolesterol oksidase dalam oksidasi kolesterol, maka dibutuhkan matriks pendukung. Enzim kolesterol oksidase diimobilisasi dengan material magnetit silikon dioksida. Material magnetit silikon dioksida disintesis melalui metode hidrotermal dengan proses pelapisan silika pada partikel magnetit. Reaksi oksidasi dilakukan dengan metode oksidasi secara langsung terhadap substrat. Penelitian ini bertujuan untuk memperoleh enzim kolesterol oksidase dari Streptomyces sp., mengimobilisasi enzim terhadap material magnetit silikon dioksida, estimasi konstanta laju reaksi oksidasi kolesterol, serta membandingkannya dengan enzim bebas dan enzim terimobilisasi. Enzim yang telah diproduksi memiliki aktivitas sebesar 5,12 U/mL. Enzim yang telah diproduksi digunakan untuk imobilisasi dan reaksi oksidasi. Variabel bebas yang digunakan dalam penelitian ini yaitu konsentrasi enzim (5;10;20 mg/mL), konsentrasi substrat (1,64;3,23;6,46 mM) dan bentuk enzim (ekstrak kasar enzim kolesterol oksidase dan enzim kolesterol oksidase terimobilisasi). Hasil karakterisasi FTIR dari material magnetit menunjukkan gugus fungsi M-O di bilangan gelombang 559,88; 598,91 dan 680,1 cm-1 gugus Si-O di bilangan gelombang 1615,78 dan 1761,65 cm-1. Hasil uji oksidasi dengan menggunakan HPLC diperoleh konsentrasi substrat secara optimal dioksidasi oleh enzim terimobilisasi dengan konsentrasi 20 mg/mL serta konsentrasi kolesterol awal 1,94 mM dengan hasil akhir sebesar 0,49 mM, sedangkan enzim kolesterol oksidase bebas mengoksidasi kolesterol dengan hasil akhir sebesar 1,459 mM.

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The formation of products related to reactions and chemical reactions, these reactions can be carried out through the kinetics model on the oxidation trend. The use of kinetics is an important aspect in achieving oxidation cholesterol levels. A catalyst of cholesterol oxidation reaction is a cholesterol oxidase enzyme. The bacteria that used as a producer of cholesterol oxidase enzyme is Streptomyces sp. Cholesterol oxidase enzymes are produced using submerged fermentation methods. To increase the effectiveness of cholesterol enzymes in cholesterol oxidation, a support matrix is needed. The cholesterol oxidase enzyme is immobilized with magnetite silicon dioxide. Magnetite silicon dioxide material is synthesized by using hydrothermal method with silica coating process. The oxidation reaction is carried out by the oxidation method directly against the substrate. The aims of this study are to produce the enzymes from Streptomyces sp., immobilize enzymes to magnetite silicon dioxide, obtaining the rate of oxidation reactions, and comparing data between free enzyme and immobilized enzyme. The produced enzyme activity was 5,12 U/mL, this enzyme is used for immobilization and oxidation reaction. In this study, the independent variables are enzyme concentration (5;10;20 mg/mL), substrate concentration (1,94; 3,23;6,46) and enzyme forms (crude extract cholesterol oxidase enzyme and immobilized enzyme). The FTIR characterization of materials have shown that metal oxide functional groups appeared at wavenumber of 559,88; 598,91 dan 680,1 cm-1- and Si-O groups at wavenumber of 1615,78 dan 1761,65 cm-1. The oxidation test by HPLC showed that the substrate concentration optimizely oxidized by immobilized enzyme with the initial concentration 20 mg/mL and substrate concentration 1,94 mM with final oxidation concentration was 1,94 mM, meanwhile the free enyme with same concentration showed 1,459 mM at final concentration."

"[ABSTRAKPendahuluan: Di Indonesia belum ada penelitian tentang injeksi silikon dan komplikasinya, walaupun kasusnya banyak. Patogenesis granuloma silikon masih belum jelas. Beberapa penelitian mengemukakan peran sel T dan sitokin, namun belum ada yang meneliti tentang toleransi imun.Metode: Penelitian ini merupakan penelitian deskriptif analitik meliputi rancangan potong lintang membandingkan 3 kelompok, yaitu 31 jaringan granuloma dan 31 kulit submental pasien dengan suntikan silikon di dagu (kasus) dan 37 kulit normal (kontrol), terhadap gambaran klinis, histopatologis, dan respons imun melalui ekspresi sitokin TNF-a, IFN-g, IL-10, enzim IDO, serta sel Treg (CD4+CD25+); Penelitian eksperimental membiakkan darah penuh kasus dan orang normal, pada RPMI, dan RPMI yang distimulasi PHA, dan silikon. Dilanjutkan dengan mengukur kadar sitokin TNF-a, IFN-g, IL-10 dan IDO supernatan biakan darah. Penelitian dilakukan di klinik spesialis JMB, FMIPA, FKUI, FKUNAIR, dan lembaga Eijkman, tahun 2012 - 2014.Hasil Penelitian: Sebanyak 31 pasien granuloma akibat suntikan silikon di dagu umumnya datang berobat 12,5 tahun setelah penyuntikan, perubahan bentuk dagu terjadi pada tahun ke-4, perubahan warna pada tahun ke-5. Kadar sitokin proinflamasi di supernatan biakan darah lebih tinggi pada pasien granuloma daripada normal. Terdapat korelasi bermakna antara TNF-a di supernatan biakan darah dengan ekspresi TNF-a di jaringan granuloma. Enzim IDO, Treg, IL-10 di kulit submental berkorelasi bermakna dengan sitokin di granuloma. Sitokin anti inflamasi berperan pada kulit submental. Rasio TNF-a/IL-10 di supernatan biakan darah berkorelasi terbalik dengan ekspresi sel Treg di granuloma, membuktikan fungsi Treg sebagai toleransi imun, bekerja melalui IL-10. Enzim IDO di granuloma berkolerasi bermakna dengan rasio TNF-a/IL-10 di supernatan biakan darah dan Treg kulit submental.Simpulan: Enzim IDO bekerja sama dengan fungsi sel Treg dalam toleransi imun pada granuloma akibat suntikan silikon. TNF-a di supernatan biakan darah dan sitokin anti inflamasi di kulit submental dapat dijadikan prediktor untuk menilai respons imun yang terjadi akibat suntikan silikon.;

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ABSTRACTBackground: There is no study on silicone injections and its complications in Indonesia, yet, although the number of cases increased. The pathogenesis of silicone granulomas is still unclear. A few studies have been made to investigate the role of T cells and cytokines, however, none investigates the role of immune tolerance.Method: An analytical descriptive study encompassing cross sectional research was designed to compare 3 groups of 31 granuloma tissue and 31 submental skin of the patients with silicone injection in the chin (case) and 37 normal skin (control) on the clinical pictures, histopathological features and immune response through the expression of TNF-a, IFN-g, IL-10 cytokines, IDO enzyme, and Treg cells (CD4+CD25+). The experimental study cultured whole blood of the case and control patients and measured the level of TNF-a, IFN-g, IL-10 cytokines and IDO enzyme. The study was conducted in JMB specialist clinics, FMIPA, FKUI, FKUA, and Eijkman foundation from the year 2012 to 2014.Result: Thirty one patients with granuloma caused by silicone injection in the chin commonly seek medical advice 12.5 years after the injection, the chin shape changed on the fourth year and the skin color changed on the fifth year. Patients with granuloma had higher level of proinflammatory cytokines in their blood cultured supernatant. There was a significant correlation between TNF-a in blood cultured supernatant with the expression of TNF-a in the granuloma tissue. IDO enzyme, Treg cells, IL-10 in the submental skin significantly correlated with the cytokines in the granulomas. Anti inflammatory cytokines played a role on the submental skin. The ratio of TNF-a/IL-10 in blood cultured supernatant reversely correlated with the expression of Treg cells in the granuloma, demonstrating the function of Treg cells as an immune tolerance working through IL-10. IDO enzyme in the granulomas significantly correlated with the ratio of TNF-a/IL-10 in blood cultured supernatant and Treg in the submental skin.Conclusion: IDO enzyme collaborates with Treg cells in the immune tolerance caused by silicone injection. TNF-a in blood cultured supernatant and anti inflammatory cytokines in the submental skin can be utilized as predictors to assess the resulting immune response due to silicone injection.;Background: There is no study on silicone injections and its complications in Indonesia, yet, although the number of cases increased. The pathogenesis of silicone granulomas is still unclear. A few studies have been made to investigate the role of T cells and cytokines, however, none investigates the role of immune tolerance.Method: An analytical descriptive study encompassing cross sectional research was designed to compare 3 groups of 31 granuloma tissue and 31 submental skin of the patients with silicone injection in the chin (case) and 37 normal skin (control) on the clinical pictures, histopathological features and immune response through the expression of TNF-a, IFN-g, IL-10 cytokines, IDO enzyme, and Treg cells (CD4+CD25+). The experimental study cultured whole blood of the case and control patients and measured the level of TNF-a, IFN-g, IL-10 cytokines and IDO enzyme. The study was conducted in JMB specialist clinics, FMIPA, FKUI, FKUA, and Eijkman foundation from the year 2012 to 2014.Result: Thirty one patients with granuloma caused by silicone injection in the chin commonly seek medical advice 12.5 years after the injection, the chin shape changed on the fourth year and the skin color changed on the fifth year. Patients with granuloma had higher level of proinflammatory cytokines in their blood cultured supernatant. There was a significant correlation between TNF-a in blood cultured supernatant with the expression of TNF-a in the granuloma tissue. IDO enzyme, Treg cells, IL-10 in the submental skin significantly correlated with the cytokines in the granulomas. Anti inflammatory cytokines played a role on the submental skin. The ratio of TNF-a/IL-10 in blood cultured supernatant reversely correlated with the expression of Treg cells in the granuloma, demonstrating the function of Treg cells as an immune tolerance working through IL-10. IDO enzyme in the granulomas significantly correlated with the ratio of TNF-a/IL-10 in blood cultured supernatant and Treg in the submental skin.Conclusion: IDO enzyme collaborates with Treg cells in the immune tolerance caused by silicone injection. TNF-a in blood cultured supernatant and anti inflammatory cytokines in the submental skin can be utilized as predictors to assess the resulting immune response due to silicone injection., Background: There is no study on silicone injections and its complications in Indonesia, yet, although the number of cases increased. The pathogenesis of silicone granulomas is still unclear. A few studies have been made to investigate the role of T cells and cytokines, however, none investigates the role of immune tolerance.Method: An analytical descriptive study encompassing cross sectional research was designed to compare 3 groups of 31 granuloma tissue and 31 submental skin of the patients with silicone injection in the chin (case) and 37 normal skin (control) on the clinical pictures, histopathological features and immune response through the expression of TNF-a, IFN-g, IL-10 cytokines, IDO enzyme, and Treg cells (CD4+CD25+). The experimental study cultured whole blood of the case and control patients and measured the level of TNF-a, IFN-g, IL-10 cytokines and IDO enzyme. The study was conducted in JMB specialist clinics, FMIPA, FKUI, FKUA, and Eijkman foundation from the year 2012 to 2014.Result: Thirty one patients with granuloma caused by silicone injection in the chin commonly seek medical advice 12.5 years after the injection, the chin shape changed on the fourth year and the skin color changed on the fifth year. Patients with granuloma had higher level of proinflammatory cytokines in their blood cultured supernatant. There was a significant correlation between TNF-a in blood cultured supernatant with the expression of TNF-a in the granuloma tissue. IDO enzyme, Treg cells, IL-10 in the submental skin significantly correlated with the cytokines in the granulomas. Anti inflammatory cytokines played a role on the submental skin. The ratio of TNF-a/IL-10 in blood cultured supernatant reversely correlated with the expression of Treg cells in the granuloma, demonstrating the function of Treg cells as an immune tolerance working through IL-10. IDO enzyme in the granulomas significantly correlated with the ratio of TNF-a/IL-10 in blood cultured supernatant and Treg in the submental skin.Conclusion: IDO enzyme collaborates with Treg cells in the immune tolerance caused by silicone injection. TNF-a in blood cultured supernatant and anti inflammatory cytokines in the submental skin can be utilized as predictors to assess the resulting immune response due to silicone injection.]"

"Riset ini difokuskan pada karakteristik linier arus-tegangan dioda P-I-N silikon skala nano doping tinggi dalam rentang temperatur dari 50K hingga 250 K serta karakteristik arus-tegangan dan konduktansi dioda P-N Silikon skala nano doping tinggi pada temperatur 5,5K. Untuk itu dioda P-N dan P-I-N dengan konsentrasi doping tinggi difabrikasi pada wafer ultra tipis berstruktur silicon-oninsulator (SOI). Dari hasil fabrikasi telah diperoleh konsentrasi doping tinggi Boron dan Phosphorus pada divais dioda mencapai 1×1020 cm-3 and 2×1020 cm-3, berturut-turut. Pengukuran karakteristik arus-tegangan dioda P-I-N silikon skala nano doping tinggi dilakukan pada beberapa divais dengan lapisan intrinsik sepanjang 200 nm dan 700 nm. Linieritas arus pada rentang forward bias dari 1,5 V hingga 2,0 V dan rentang temperatur dari 50 K hingga 250 K menunjukkan divais ini sesuai untuk sensor temperatur rendah. Pada pengukuran juga diperoleh data bahwa dioda P-I-N silikon skala nano doping tinggi menghasilkan arus yang lebih tinggi saat temperatur diturunkan dalam rentang forward bias dari 1,5 V hingga 2,0 V. Selain itu juga diperoleh data bahwa divais skala nano dengan lapisan intrinsik yang lebih panjang dan lebih lebar akan menghasilkan arus yang lebih tinggi pada rentang forward bias dari 1,5 V hingga 2,0 V dan temperatur dari 50K hingga 250K. Hasil pengukuran pada dioda P-N silikon skala nano doping tinggi pada rentang forward bias hingga 0,1 Volt maupun rentang reverse bias hingga -0,1 Volt menghasilkan beberapa puncak konduktansi yang menunjukkan kesesuaian nilai dengan level energi density of state dua dimensi (2D DOS) dan level energi kombinasi phonon pada temperatur 5,5K. Pada forward bias, level energi diskret heavy hole, light hole, serta kombinasi phonon TA, LA, TO dan LO berkontribusi signifikan pada puncak konduktansi dalam rentang tegangan hingga 0,1 Volt. Demikian juga halnya pada reverse bias, level energi diskret elektron 2-fold valley, 4-fold valley, serta kombinasi phonon TA, LA, TO dan LO berkontribusi signifikan pada puncak konduktansi dalam rentang tegangan hingga -0,1 Volt. Transport elektron pada dioda P-N Silikon dalam skala nano doping tinggi akan mengalami puncak konduktansi saat elektron memiliki energi yang sama dengan level diskret energi 2D DOS. Hal ini membuktikan adanya phonon-assisted tunneling pada dioda P-N silikon skala nano doping tinggi.

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This report is focused on linier current-voltage (I?V) characteristic of highly-doped nanoscale Silicon P-I-N diodes at temperature from 50K to 250K and also I-V and conductance characteristics of highly-doped nanoscale Silicon P-N diode at temperature 5.5K. For that purpose, we fabricated nano scale P-I-N and P-N diodes within ultra thin silicon-on-insulator (SOI) structures. From fabrication, we achieved high doping concentrations of Boron and Phosphorus in SOI diodes, 1×1020 cm-3 and 2×1020 cm-3, respectively.

Measurement of current-voltage characteristics of highly-doped nanoscale silicon PIN diode is performed on devices with intrinsic layer length of 200 nm and 700 nm. The current linearity under forward bias range from 1.5 V to 2.0 V and temperature range from 50K to 250K shows that these devices are suitable for lowtemperature sensor. The measurement data shows also that highly-doped nanoscale silicon PIN diode produces higher current when the temperature is lowered under forward bias from 1.5 V to 2.0 V. In addition, the data shows that nanoscale devices with longer and wider intrinsic layer would generate higher current under forward bias range from 1.5 V to 2.0 V and temperature from 50K to 250K.

Measurement of highly-doped nanoscale silicon P-N diode under forward bias to 0.1 Volt and also reverse bias to -0.1 Volt results conductance peaks that show relationship with two-dimensional density of state (2D DOS) and phonon combination energy level at temperature 5.5K. Under forward bias, discrete energy level of heavy hole, light hole and phonon combination of TA, LA, TO and LO have significant contribution to conductance peaks in range 0.1 Volt. Also under reverse bias, discrete energy level of electron 2-fold valley, 4-fold valley and phonon combination of TA, LA, TO and LO have significant contribution to conductance peaks in range -0.1 Volt. Electron transport of highly-doped nanoscale silicon P-N diode will experience conductance peaks when it has equal energy with 2D DOS discrete energy level. It proves the existence of phonon-assisted tunneling on highly-doped nanoscale silicon P-N diode."

"ABSTRAKHidrogen telah diketahui sebagai faktor penting untuk produk semikondukor silikon. Silikon sebagai material yang paling melimpah dan layak sebagai semikonduktor membutuhkan kondisi layak untuk didapatkan sifat listrik dan optik yang tepat. Fenomena adsorpsi hidrogen pada silikon telah dipelajari menggunakan simulasi komputasi dan eksperimen oleh para peneliti. Simulasi dinamika molekuler menggunakan potensial Lennard-Jones telah dilakukan untuk mendemonstrasikan kemampuan adsorpsi hidrogen permukaan silikon (001) dan (111) dengan variasi temperatur sebesar 233 K, 253 K, 273 K, dan 293 K yang diterapkan pada tekanan 1, 2, 5, 10, dan 15 atm. Berdasarkan hasil simulasi, didapatkan jumlah hidrogen yang diadsorpsi oleh permukaan silikon meningkat apabila jumlah panas dalam sistem berkurang. Tanpa meninjau aspek entropi, permukaan kristal Si (001) memiliki kemampuan adsorpsi lebih tinggi dibandingkan Si (111) disebabkan oleh energi bebas permukaan yang lebih tinggi. Hal tersebut jelas terlihat pada tekanan 15 atm dibandingkan variasi tekanan lainnya Kapasitas adsorpsi paling tinggi dimiliki oleh Si (001) 233 K pada 15 atm dengan jumlah konsentrasi hidrogen teradsorpsi 0,166430075% wt., dan paling rendah dimiliki oleh Si (111) 293K pada 1 atm senilai 0,004759865% wt.

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ABSTRACTHydrogen was known as important factor for silicon semiconductor product. Silicon as the most abundant and feasible material for semiconductor needs precisely proper condition to have the exact optical and electrical properties. The hydrogen adsorption on silicon phenomena had been studied through computational simulations and experiment by researchers. Molecular dynamics simulation using a Lennard-Jones potential was conducted to demonstrate the hydrogen adsorption capability of silicon surface (001) and (111) with various temperatur applied, 233 K, 253 K, 273 K, and 293 K at pressure 1, 2, 5, 10, dan 15 atm. The amount of hydrogen adsorbed by silicon surfaces were higher as the amount heat of the system decreases. Without considering entropy, Si (001) had higher adsorption capability due to its higher energy surface than Si (111). It had shown where the pressure was at 15 atm, the difference seemed way more obvious than other pressure condition. Si (001) on 233 K at 15 atm had the highest adsorption capacity with 0,17% wt., of hydrogen. The lowest amount of hydrogen capacity was achieved by Si (111) on 293 K at 1 atm with 0,0048% wt."