Papers by Keyword: Electrical Properties

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Authors: Stefania Privitera, Vincenza Brancato, Donatella Spadaro, Ruggero Anzalone, Alessandra Alberti, Francesco La Via
Abstract: The electrical and optical properties of n-doped polycrystalline 3C-SiC films grown on 6 inches Si wafers have been investigated as a function of precursor gases, deposition temperature and C/Si ratio. The Si/SiC interface has been optimized, eliminating the voids formation through a double temperature step process and by introducing a thin not intentionally doped layer. Films with high surface roughness, favourable for light trapping in photovoltaic applications, and with resistivity around 20 mOhm cm have been obtained for C/Si ratio close to 1. Simple solar cells have been also manufactured and proved the functionality of poly 3C-SiC/Si heterojunction solar cell. Increased quantum efficiency in the range 300-500 nm has been observed, compared to amorphous Si, making poly 3C-SiC heterojunction solar cells interesting for high temperature applications or water splitting.
Authors: Tehreem Kanwal, Rub Nawaz Shahid, Naeem Ul Haq Tariq, Fahad Ali, M. A. Rafiq, Muhammad Iqbal, J.I. Akhter, Bin Awais Hasan
Abstract: The ceramic-metal composites that have all phases continuous throughout the structure are known as Interpenetrating Phase Composites (IPCs) and they have many applications in various fields. In this investigation ZrO2-Ni IPCs of varied compositions were synthesized using tubular furnace and microwave furnace routs. Samples were Characterized using BET surface area, Pycnometer density, dilatometry and scanning electron microscopy. The Electrical parameters of the composites were measured using impedance spectrometer. Results indicate that threshold percolation reached at 40 volume percent of Ni in both cases. Moreover, no significant difference was observed in BET surface area and CTE of composites prepared by conventional and microwave sintering processes.
Authors: Daniela Cristina Berger, Ioana Jitaru, C. Matei, J. Schoonman
Authors: Nurul Azuwa Azmi, Umar Al Amani Azlan, Maziati Akmal Mohd Hatta, Mohd Asyadi' Azam Mohd Abid, Mohd Warikh Ab Rashid
Abstract: (K, Na)NbO3 (KNN) thin films were prepared by sol-gel technique. Spin coating deposition and rapid thermal annealing (RTP) process were applied to produce the KNN thin films. The films obtained demonstrated that highly crystallographic orientation was produced at five layer deposition with increase (preferred orientation) peak at (1 1 1). The thickness of five layers thin films observed by field emission scanning electron microscopy (FE-SEM) was determined to be ~200nm. However, the inhomogeneous distribution of KNN particles was detected in KNN thin films. The distribution of KNN elements was confirmed by energy-dispersive X-ray (EDX) spectra. Improvement was observed in resistivity (2.71-7.81x106 Ω.cm) and dielectric loss (0.35%-0.21%) following the increasing number of layers.
Authors: Lan Zhang, Atsushi Hosoi, Yang Ju
Abstract: Using the microwave atomic force microscope (M-AFM) measuring system, the sample of Au nanowires arranged on glass wafer was sensed with three kinds of scanning speed. As the results shown, the spatial resolution of topographies is increased with the decrease of scanning speed. However, the precision of microwave images is not changed much with decreasing the scanning speed. Since M-AFM with the compact microwave instrument can always implement the real time measurement, the variation of scanning speed will not affect the microwave measurement.
Authors: Sabah Jalal Fathi
Abstract: The electrical resistivity of high temperature superconductivity Tl2-xHgxBa2Ca2Cu3O10- δ has been measured in the temperature range from 90K to 330K. These results showed that the critical temperature of the zero resistivity increases from 127K to 138K ,when the Hg concentration increased from 0 to 0.5. The structure of the Tl2-xHgxBa2Ca2Cu3O10-δ compound has also investigated by using X- ray diffraction technique. This compound has tetragonal type structure with a=b=5.36A & c=36.09A and the magnitude of c-axis increases to 37.8A when x increased to 0.5. Nano ZnO was add to the sample with concentration (0-1) wt% of the ( Tl2- xHgxBa2Ca2Cu3O10- δ) samples mass. The effect of the nano ZnO concentration substitution on the samples investigated on structure and critical temperature of the best sample properties (when x=0.5)and showed that the structure remains tetragonal and c-axis increased to 39.2A when nano sized concentration 0.8% and Tc increase to 146K but c-axis decreased to 38.4A and Tc decreased to 143K when the ZnO concentration 1%.
Authors: Antonella Parisini, Roberta Nipoti
Abstract: The knowledge of the Hall factor is essential to convert Hall to drift transport data, in order to fit them and reliably evaluate doping and compensation levels of samples. By introducing empirical mass anisotropy factors, reasons were given in favour of a generalized use of the unique experimental evaluation of the Hall factor reported by the literature for p-type 4H-SiC, which has been assessed for an Al acceptor density in the range of 1.8×1015 - 2×1018 cm-3. Using such a curve, carrier transport data, taken in Al+ implanted 4H-SiC for an Al concentration of 5×1019 cm-3 after either 2000°C/30s microwave annealing or 1950°C/300s conventional annealing, were analysed through a standard relaxation time approximation model. A slight difference was evidenced in the compensation level of the samples, also resulting in a different ionization energy of the acceptor.
Authors: Zhi Qiang Wang, Yun Bo Zhong, Kang Deng, Zhong Ming Ren
Abstract: A direct current was imposed during the ageing treatment of cold worked Cu-Cr-Zr alloys. The effect of increasing current density and ageing time on the electrical conductivity and microhardness has been investigated. The electrical conductivity was found to increase by about 22% IACS to a maximum value of 90% IACS. Furthermore, the microhardness increased by 21 HV up to 176 HV. A number of Cr precipitates and Cr-rich clusters were observed after the ageing treatment with direct current. The direct current was found to significantly enhance the efficiency of precipitation which is most probably due to the electron wind force and the electromigration-induced mass transport.
Authors: A.N. Fadzilah, Nur Ayuni Tahir, Mohamad Rusop
Abstract: This paper reports on the deposition of semiconducting amorphous carbon (p-aC) films fabricated onto the glass substrate and n-type silicon by Thermal Chemical Vapor Deposition (CVD) using natural source of camphoric carbon as the precursor material. Those samples were deposited at 5 different temperatures from 3500C to 5500C. From the characterization of the electrical properties using current-voltage (I-V) measurement, I-V graph was modeled for both conditions, where for a-C thin films linear graph (ohmic) were performed, whereas for the device, a rectifying graph were obtained. The analyze revealed that conductivity shows an increment as deposition temperature increased, both in dark and under illumination condition. On the other hand, the solar cell device of the p-aC/n-Si achieved an efficiency of 0.1111% for the a-C deposited at 3500C. Other than that, optical properties were also characterized by using UV-VIS-NIR system. The same trend of optical and electrical can be seen when the measurement from the Tauc’s plot expose a decreasing value of optical band gap as temperature increase.
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