Judul: Pengaruh Variasi Konsentasi Pendadah RuO2 Terhadap Struktur Kristal Dan Sifat Optik Dari Film Tipis BaTiO3
Abstrak: Pembuatan film tipis BaTiO3 bertujuan menganalisis sifat optik, struktur morfologi spectra XRD, dan citra SEM-EDAX. Film tipis Barium Titanat (BaTiO3) murni dan BaTiO3 dengan variasi pendadah RuO2 2%, 4%, dan 6% yang ditumbuhkan pada silikon tipe-p (100) dengan metode Chemical Solution Deposition (CSD). Film BaTiO3 dan BaRuTiO5 dibuat dalam konsentrasi 2 M. Film tersebut ditumbuhkan dengan tiga kali pelapisan menggunakan teknik spin coating pada kecepatan putar 6000 rpm, 8000 rpm, dan 10000 rpm selama 30 detik. Film kemudian di annealing pada suhu 850 oC selama 8 jam. Film dikarakterisasi menggunakan spektrofotometer UV-Vis untuk mengetahui sifat optik berupa analisis nilai reflektansi, indeks bias dan energy gap. Metode ini memiliki keunggulan dapat mengontrol stokiometri film tipis dengan kualitas yang baik, prosedur yang mudah dan biaya yang relatif murah. Energi band gap berkisar 3.25 sampai 3.27 eV dengan indeks bias 2.7749894 sampai 2.77498944. Film tipis BaTiO3 memiliki parameter kisi a = 4.035 sampai 4.097 Ǻ dan c = 4.043 sampai 4.107 Ǻ serta ukuran kristal berada pada rentang 0.175 μm sampai 0.5 μm.
Keyword: film tipis, sifat optik, barium titanat, chemical solution deposition, pendadah, ruthenium oksida

Judul: Characterization of the crystal structure and optics of  BaTiO3 thin film in Ruthenium powder
Abstrak: Sintesis dan karakterisasi film tipis BaTiO3 dengan variasi konsentrasi pendadah Rutenium 0%; 0,5%; dan 1% telah berhasil dilakukan menggunakan metode Chemical Solution Deposition. Film BaTiO3 yang dibuat dalam konsentrasi 2M ditumbuhkan dengan teknik spin coating dalam lima kali pelapisan dengan kecepatan putar 3000 rpm selama 30 detik dan melalui proses annealing selama 8 jam pada suhu 850°C. Film tipis BaTiO3 dikarakterisasi dengan XRD, UV-Vis dan FTIR untuk menganalisis struktur kristal dan sifat optik sampel. Hasil karakterisasi XRD dengan metode Cramer- cohen dan software MAUD menunjukkan bahwa parameter kisi semakin berkurang dan struktur kristal tetap berbentuk tetragonal. Karakterisasi spektrofotometer UV-Vis menunjukan peningkatan nilai reflektansi pada rentang panjang gelombang 380 - 600 nm dengan peningkatan nilai energi bandgap dari analisis Kubelka-Munk untuk direct bandgap sebesar 2,41 eV, 3,37 eV dan 3,42 eV. Kemudian karakterisasi spektroskopi FTIR mengadopsi relasi Kramers-Kronig diperoleh indeks bias (n), koefisien extinction (k) dan parameter dielektrik bagian real (ε1) juga bagian imajiner (ε2) pada bilangan gelombang dengan penambahan pendadah Rutenium memperkecil medan listrik dan menyebabkan penurunan nilai moda optik TO dan LO yang memengaruhi konstanta optik sampel., Synthesis and characterization of BaTiO3 thin films with various concentrations of 0%; 0,5%; and 1% ruthenium scavenger has been successfully carried out using the Chemical Solution Deposition method. The BaTiO3 film prepared in a concentration of 2M was grown using the spin coating technique in five layers with a rotational speed of 3000 rpm for 30 seconds and annealed for 8 hours at 850°C. BaTiO3 thin films were characterized by XRD, UV-Vis and FTIR to analyze the crystal structure and optical properties of the samples. The results of the XRD characterization using the Cramer- Cohen method and MAUD software show that the lattice parameters decrease and the crystal structure remains tetragonal. Characterization of the UV-Vis spectrophotometer shows an increase in reflectance values in the wavelength range of 380-600 nm with an increase in the bandgap energy value from the Kubelka-Munk analysis for direct bandgap of 2,41 eV, 3,37 eV and 3,42 eV. Then the FTIR spectroscopic characterization adopts the Kramers-Kronig relation obtained refractive index (n), extinction coefficient (k) and the dielectric parameters of the real part (ε1) as well as imaginary part (ε2) in wave numbers with the addition of ruthenium divider reduce the electric field and causes a decrease in moda value optical TO and LO which affect the optical constant of the sample.
Keyword: BaTiO3, bilangan gelombang, CSD, energi bandgap, parameter kisi, bandgap energy, lattice parameters, wavenumber

Judul: Lejeuneaceae Subfamily Ptychanthoideae (Hepaticae) in  West Java
Abstrak: Subfamily Ptychanthoideae of the family Lejeuneaceae (Hepaticae) in West Java is still poorly known. Publications on this subfamily are out of dated and written in the 19th or early of 20th century. The last taxonomic treatment of Ptychanthoideae of West Java was in 1933, many species names have changed since then. Studies on Ptychanthoideae of West Java are urgently needed. Studies on the Ptychanthoideae were based on the specimens collected from West Java. A total number of 361 of specimens deposited in the Herbarium Bogoriense (BO), Herbarium Biotrop (BIOT), Gottingen Herbarium (GOET) and Bangi Herbarium (UKMB) were examined, those are old and several recent specimens collected in West Java. Recent collections were made from Telaga Warna, Ciater, Gunung Halimun Salak National Park, Cibodas Botanical Garden, Bodogol Education Center and Conservation (Gunung Gede Pangrango National Park), University of Indonesia Campus Depok, including several collections from Banten Province. Twenty four species of Lejeuneaceae subfamily Ptychanthoideae are known from West Java, belonging to 8 genera namely Acrolejeunea (Spruce) Schiffn. (2 species), Archilejeunea (Spruce) Schiffn. (1 species), Lopholejeunea (Spruce) Schiffn. (10 species), Mastigolejeunea (Spruce) Schiffn. (3 species), Ptychanthus Nees (1 species), Schiffneriolejeunea Verd. (1 species), Spruceanthus Verd. (2 species) and Thysananthus Lindenb. (4 species). Two new records of Ptychanthoideae: Mastigolejeunea indica Steph. and Thysananthus minor Verdoorn are reported for Java. A determination key to the species is presented including their descriptions and illustrations.
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