Electrodeposition of Ni-Si Schottky barriers

Electrodeposition is being used to fabricate magnetic microstructures directly on patterned n-type Si wafers of various substrate resistivities. The Ni-Si Schottky barrier is characterized and found to be of high quality for relatively low Si resistivities (1-2 Omega(.)cm), with extremely low reverse leakage. It is shown that a direct correlation exists among the electrodeposition potential, the roughness, and the coercivity of the films. A conductive seed layer or a back contact is not compulsory for electrodeposition on Si with resistivities up to 15 Omega(.)cm. This shows that electrodeposition of magnetic materials on Si might be a viable fabrication technique for magnetoresistance and spintronics applications

PENGGUNAAN ZEOLIT SEBAGAI MODIFIER ELEKTRODA PASTA KARBON UNTUK ANALISIS Cd (II) SECARA CYCLIC STRIPPING VOLTAMETRY

Abstrak Penelitian ini merupakan penelitian tentang penggunaan zeolit sebagai modifier elektroda pasta karbon untuk analisis Cd (II) secara cyclic stripping voltametry. Tujuan dilakukan penelitian ini adalah untuk menentukan perbandingan komposisi terbaik dari elektroda pasta karbon yang dimodifikasi dengan zeolit dengan perbandingan karbon : minyak parafin : zeolit adalah 3:2:5, 3:3:4, 3:4:3, 3:5:2. Pengukuran dilakukan dengan menggunakan instrumen voltametri dengan menggunakan metode cyclic stripping voltametry. Pengukuran larutan analit Cd (II) dengan konsentrasi 5 ppm dengan metode ini dihasilkan komposisi elektroda terbaik dengan perbandingan 3:5:2. Pengukuran optimasi dilakukan dengan memvariasi buffer pH pada pH 3, 4, 5, dan 6, waktu deposisi pada 0, 10, 40, 80, dan 100 detik serta laju pindai 10, 20, 40, 50 dan 60 mV/detik, dan pengaruh interfensi ion logam pengganggu Mn (II) dan Ni (II). Berdasarkan dari penelitian ini diperoleh pH optimum pada pH 6 dengan arus puncak Ipc -3.666 mA dan Epc -0.656 mV. Lama waktu deposisi optimum yang didapatkan adalah 10 detik dengan arus puncak Ipc -6.382 mA dan Epc -0.661 mV. Lama laju pindai optimum yang dihasilkan dari pengukuran tersebut adalah 0,05 V/detik dengan arus puncak Ipc 8.624 mA dan Epc -0.925 mV. Penambahan ion pengganggu Mn (II) dan Ni (II) pada analisis Cd (II) secara cyclic stripping voltametry memiliki pengaruh yang cukup besar sehingga dalam pengukurannya tidak disarankan diberikan ion pengganggu. Persen Recovery larutan Cd (II) 5 ppm diperoleh sebesar 97,93%. Kata kunci : elektroda pasta karbon, voltametri, zeolit Abstract The research of the using of zeolite as the carbon paste electrode modifier for the analysis of Cd (II) has been done. This research aims to determine the best ratio composition of electrode carbon paste modified zeolite with a ratio of carbon: paraffin: zeolite is 3:2:5, 3:3:4, 3:4:3, 3:5:2. Measurements were made using instruments voltametry with cyclic stripping voltametry method. Measurement of Cd (II) at a concentration of 5 ppm with this produced the best electrode composition with a ratio of 3: 5: 2. Measurements were performed by varying the pH buffer at pH 3, 4, 5, and 6, deposition time at 0, 10, 40, 80, and 100 seconds and scan rate 10, 20, 40, 50 and 60 mV/sec, and the effect of metal ion interference Mn (II) and Ni (II). The resulting of this research is pH optimum at pH 6 with a peak current Ipc Epc -3666 mA and -0656 mV. Obtained optimum deposition time was 10 seconds with a peak current Ipc -6382 mA and Epc -0661 mV. Long produced the optimum scan rate is 50 mV/sec with peak currents Ipc -8624 mA and Epc -0925 mV. Ion interferens Mn (II) and Ni (II) was added on the analysis of Cd (II) are cyclic stripping voltametry has considerable influence so that the measurement is not advisable given interferens ion. The percent result of recovery with Cd (II) at a concentration of 5 ppm is 97,93%. Keywords: zeolites, carbon paste electrodes, voltammetr

Carbon-Based Fibrous EDLC Capacitors and Supercapacitors

This paper investigates electrochemical double-layer capacitors (EDLCs) including two alternative types of carbon-based fibrous electrodes, a carbon fibre woven fabric (CWF) and a multiwall carbon nanotube (CNT) electrode, as well as hybrid CWF-CNT electrodes. Two types of separator membranes were also considered. An organic gel electrolyte PEO-LiCIO4-EC-THF was used to maintain a high working voltage. The capacitor cells were tested in cyclic voltammetry, charge-discharge, and impedance tests. The best separator was a glass fibre-fine pore filter. The carbon woven fabric electrode and the corresponding supercapacitor exhibited superior performance per unit area, whereas the multiwall carbon nanotube electrode and corresponding supercapacitor demonstrated excellent specific properties. The hybrid CWF-CNT electrodes did not show a combined improved performance due to the lack of carbon nanotube penetration into the carbon fibre fabric

Mercury Analysis and Concentration in Seawater of Southern Sumbawa

. Current concerns over the negative impacts of Hg in the environment have led to the rapid progress of studies in this area. This progress has been directed to obtain analysis techniques that are able to accurately quantify Mercury (Hg) at extremely low concentration in which it frequently occurs. As part of a study on the environmental aspects of deep-sea submarine tailing placement at the Batu Hijau Mine, Sumbawa, this paper discusses recent progress in Hg analytical techniques, followed by the application of several techniques to investigate Hg concentration in seawater in the vicinity of the tailing discharge location. Using cold vapour atomic fluorescence spectrometry, dissolved Hg was found to be at sub-ng/l (ppt) levels. No dissolved Hg signal associated with the tailing discharge was found with concentrations being similar to adjacent coastal waters

Fundamental electrode kinetics

Report presents the fundamentals of electrode kinetics and the methods used in evaluating the characteristic parameters of rapid-charge transfer processes at electrode-electrolyte interfaces. The concept of electrode kinetics is outlined, followed by the principles underlying the experimental techniques for the investigation of electrode kinetics