Papers by Keyword: CV

Abstract: We discuss two defect related practical improvements in the corona noncontact CV metrology, (CnCV) for SiC. The improvements are introduced in response to requests from industrial tool users. The first improvement quantifies mapping of electrically active defects with the QUAD technique (Quality, Uniformity, and Defects). It provides the capability of user selectable die grids directly comparable with Near UV-PL and optical defect mapping. This shall enhance understanding of the device killer defects and help to correlate epilayer defects and device yield. The second improvement introduces auto-remeasurement of outliers appearing in doping measurements on defective sites. This procedure is analogous to that used in the Hg probe technique and it provides a means for correcting defect related distortions in SPC doping monitoring charts.

Abstract: Cobalt oxide thin film (Co₃O₄) has been prepared from cobalt chloride with distilled water on conducting glass substrates Fluorine doped Tin Oxide (FTO) at (400^ºC) by depositing chemical spray pyrolysis, with thickness (200 nm). The structural properties are studied by XRD. Also, optical properties and electrical properties of Co₃O₄ thin film are studied by UV spectroscopy and Cyclic voltammetry (CV) respectively. The effects of gamma irradiation on optical properties are also examined. XRD results showed that the film was polycrystalline with cubic structure having preferred orientation (111). The as-prepared Co₃O₄ film exhibits a noticeable EC behaviour with reversible colour which changes from dark grey to pale yellow with bleaching time (55 s) and colouring time (40 s). After irradiation, the optical properties showed that as the transmittance decrease leads to decrease the direct optical band gap from (3.68eV) to (3.55eV)

Abstract: Three electrochemical double layer capacitor (EDLC) cells (Cell X, Y and Z) made from an electrode of 90 wt. % of the multiwalled commercial carbon nanotubes, 10 wt. % of poly (vinylidene fluoride-co-hexafluoropropylene) and three different samples of electrolytes polymer electrolyte made up of a compositions of 50:50, 60:40 and 70:30 wt.% of H₃PO₄/PVA (in ratio) soaked in a filter paper was characterized in this study. The aim is to ascertain the disparities in performances of the cells in relation to their respective scan rates. Cyclic voltammetry (CV) measurement of cells shows a high specific capacitance of 313 Fg⁻¹ for the scan rates 10 mV was recorded from the cell with the highest composition H₃PO₄/PVA ratio (i.e. 70:30 wt.%). However, when the CV of the cell was measured with different scan rates, disparities in the performance occurred, as only 94 and 174 Fg⁻¹ was recorded at the scan rates 100 and 50 mV respectively for cell-X. The result was not different when the two other cells (60:40 and 70:30 wt. % of H₃PO₄/PVA) were measured at the same scan rates.

Abstract: Cuprous oxide (Cu₂O) is a promising material for solar cell application. Due to its various advantages over silicon material, it has been exploited extensively to be use in photovoltaic cell. Cu₂O thin films were electrodeposited in sulfate-based solution. Cyclic voltammorgram (CV) measurement was used to investigate the reduction process under controlled parameters. Deposition potential of-0.1V vs. Ag/AgCl was used for the fabrication of Cu₂O thin film based on the CV measurement. CV also revealed that the deposition speed was dependent on the bath pH and the temperature. X-ray diffraction (XRD) measurement, Field Emission Scanning-Electron Microscopy (FE-SEM) and Ultraviolet-visible spectroscopy (UV-Vis) were performed to characterize the deposited thin films. The n-Cu₂O was successfully fabricated on FTO glass substrate with (111)-prefered orientation. Surface morphology of the thin films were observed to be in flower-like shape combination with pyramidal and triangular shape.

Abstract: Lateral MOSFET devices with a thin surface counter-doped layer using Sb and As with and without NO passivation have been fabricated and characterized. The results demonstrate that Sb and As counter-dope the interface without significant trap passivation while in combination with NO there is a superposition of both trap passivation and counter-doping related performance enhancement. In addition, by varying the counter doping level, a universal mobility characteristics of NO passivated devices has been identified.

Abstract: Poly (methyl) methacrylate (PMMA)-based gel polymer electrolytes (GPEs) containing magnesium triflate, Mg (CF₃SO₃)₂ salt were prepared using solution casting technique. Different concentrations of Mg (CF₃SO₃)₂ ranging from 5 wt.% to 30 wt.% have been added into a mixture of ethylene carbonate (EC) and propylene carbonate (PC) with a fixed mass ratio of 2:1. These free-standing GPE films were characterized using electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV) and cyclic voltammetry (CV). The highest ionic conductivity of 1.27 x 10^-3 S cm^-1 is obtained from the GPE film containing 20 wt.% of Mg (CF₃SO₃)₂ salt. The electrochemical window stability has been found in the range of-2.5 V to 2.5 V for the highest conducting GPE film. This value is considerably high enough for the GPE film to be used as electrolyte in magnesium rechargeable batteries.

Abstract: Nanostructured manganese oxide films were obtained by electro-oxidation of manganese films electrodeposited at two typical cathodic currents of 65 mA cm^-2 (EDM-65 oxide) and 150 mA cm^-2 (EDM-150 oxide) from sulfate solutions with additives. Obtained Mn oxide films were studied by scanning electron microscope, X-ray photoelectron spectroscopy, cyclic voltammetry and AC impedance. SEM study revealed that the Mn oxide films were mesoporous nanostructures on the EDM-150 oxide surface, while the EDM-65 oxide coating is homogeneous and compact. XPS results indicate that EDM-150 oxide had a higher content of anhydrous Mn oxide and structure water, which means that it had more anhydrous characteristics as compared to EDM-65 oxide. It was shown that porous nanostructured films showed good capacitive behavior for applications in electrochemical supercapacitors. The porous nanostructured films prepared at 150 mA cm^-2 showed higher specific capacitance (SC) compared to the SC of the EDM-65 oxide films. The highest SC of 148 F g^-1 in a voltage window of 0.8 V was obtained in 0.1 M Na₂SO₄ solutions at a scan rate of 25 mV s^-1.

Abstract: A simple electrochemical test system based on aptasensor for ATP detection is constructed in this paper. This system includes a home-made signal conditioning module, a Data Acquisition Card, a personal computer installed with LabVIEW and a self-assembly aptasensor. The electrochemical control programs are developed in LabVIEW, which generated drive signals, scanned the potential of the working electrode, acquired and stored the data, queried and displayed the results. This electrochemical test system is in small dimension, which makes it suitable for in-field measurements. In order to clarify the electrochemical properties of the electrochemical test system, cyclic voltammetry (CV) was used to monitor the process in details.

Abstract: In today`s scenario of depleting conventional fossil fuels biomass provides an alternate source of energy. Gasification is a chemical process that converts carbonaceous materials like biomass into useful convenient gaseous fuels or chemical feedstock. The gasification process uses an agent air or oxygen, hydrogen or steam to convert carbonaceous materials into gaseous products. As air gasification produces poor quality syngas, oxygen is used as gasifying agent for biomass gasification. Biomass gasification with oxygen as gasifying agent has great potential in applications like IGCC (Integrated Gasification combined cycle), Chemical Production and Fischer-tropsch products. In this paper the simulation model of a biomass gasifier for different biomass like charcoal, rice husk and wood pellets with oxygen and air as a gasifying agent is developed using ASPEN Plus. The model predicts syngas composition, heating value, temperature, pressure and quantity of gas produced. These results are obtained for various feedstocks like wood pallets, rice husk, and Indian coal on the basis of proximate and ultimate analysis.

Abstract: The Li[Li0.2Co0.4Mn0.4]O2 cathode material was prepared by a sol-gel method. Combinative X-ray diffraction (XRD) studies showed that the material was a solid solution of LiCoO2 and Li2MnO3. The material showed a reversible discharge capacity of 155.0 mAhg−1 at -20 °C, which is smaller than that at room temperature (245.5 mAhg−1). However, the sample exhibited capacity retention of 96.3 % at -20 °C, only 74.2 % at 25 °C. The good electrochemical cycle performance at low temperature was due to the inexistence of Mn3+ in the material.