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81.
Andrzej Taube Robert Mroczyński Katarzyna Korwin-Mikke Sylwia Gierałtowska Jan Szmidt Anna Piotrowska 《Materials Science and Engineering: B》2012,177(15):1281-1285
In this work, we report on effects of post-deposition annealing on electrical characteristics of metal–insulator–semiconductor (MIS) structures with HfO2/SiO2 double gate dielectric stacks. Obtained results have shown the deterioration of electro-physical properties of MIS structures, e.g. higher interface traps density in the middle of silicon forbidden band (Ditmb), as well as non-uniform distribution and decrease of breakdown voltage (Ubr) values, after annealing above 400 °C. Two potential hypothesis of such behavior were proposed: the formation of interfacial layer between hafnia and silicon dioxide and the increase of crystallinity of HfO2 due to the high temperature treatment. Furthermore, the analysis of conduction mechanisms in investigated stacks revealed Poole–Frenkel (P–F) tunneling at broad range of electric field intensity. 相似文献
82.
Characteristic of polychlorinated dibenzo-p-dioxins and dibenzofurans in fly ash from incinerators in china 总被引:4,自引:0,他引:4
Chen T Yan JH Lu SY Li XD Gu YL Dai HF Ni MJ Cen KF 《Journal of hazardous materials》2008,150(3):510-514
Fly ash from municipal solid waste (MSW), medical waste (MW) and electrical power plant (EPP) incinerators were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). The study showed that the PCDD/F levels in fly ash were EPP < MSW < MW. The homologue profiles of PCDD/Fs in fly ash produced from waste incinerators were similar. However, the homologue profiles of PCDD/Fs in fly ash from electrostatic precipitator (ESP) of electrical power plant were different from that from waste incinerator. The strong correlation was found between the concentration of 2,3,4,7,8-PeCDF and the I-TEQ value of fly ash regardless of the different fly ashes sources. 相似文献
83.
Thin films of Al, Sc-co-doped ZnO varying with Sc-contents were sputtered on the glass substrate. X-ray diffraction (XRD) of the films revealed wurtzite crystals that were confirmed through the analysis of high resolution transmission electron microscopy (HRTEM). With increasing the Sc-content from 0 to 2.37 wt.% in the films, the optical energy band gap (Eg) was estimated to decrease from 3.25 to 3.20 eV, and the electrical resistivity (Ω cm) decreased from 3.8 × 10− 3 to 1.3 × 10− 3. The decrease in resistivity may be ascribed to electrons tunneling through the horizontal stacking faults induced by Sc-dopants in the films. 相似文献
84.
Hydrogen sulfide (H2S) was introduced into a microwave plasma chemical vapor deposition of microcrystalline diamond thin film. Secondary-ion mass spectroscopy showed that sulfur concentration was controlled from 2 × 1015 to 9 × 1017 cm− 3 by controlling the H2S/CH4 ratio, while that of hydrogen concentration was around 5 × 1020 cm− 3 and was independent of the H2S/CH4 ratio. Electrical conductance increased linearly as the S concentration increased from 2 × 1015 to 3 × 1016 cm− 3 without significant deterioration of film crystallinity, i.e., the amount of sp2 phase did not increase. Non-ohmic conduction was converted to ohmic conduction when the S concentration reached 9 × 1017 cm− 3 by increasing the H2S/CH4 ratio to 30,000 ppm. This modification was consistent to the formation of a graphitic phase by heavy S-doping, which was identified by Raman spectra and surface morphology. 相似文献
85.
Transparent and conductive Al-doped ZnO (AZO) films have been grown with various thicknesses between 0.3 and 1.1 μm by magnetron sputtering at room temperature onto soda lime glass substrates. After deposition, the samples have been annealed at temperatures ranging from 150 to 450 °C in air or vacuum. The optical, electrical, and structural characteristics of the AZO coatings have been analyzed as a function of the film thickness and the annealing parameters by spectrophotometry, Hall effect measurements, and X-ray diffraction. As-grown layers are found polycrystalline, with hexagonal structure that shows some elongation of the unit cells along the c-axis, having visible transmittance ∼85-90% and resistivity ∼1.6-2.0 mΩ cm, both parameters slightly decreasing when the film thickness increases. Heating in air or vacuum produces further elongation of the crystalline lattice together with some increase of the visible transmittance and a decrease of the electrical resistance that depends on the heating temperature and atmosphere. The best characteristics have been obtained after treatment in vacuum at 350 °C, where the highest carrier concentrations are achieved, giving visible transmittance ∼90-95% and resistivity ∼0.8-0.9 mΩ cm for the AZO layers with various thicknesses. Some relationships between the analyzed properties have been established, showing the dependence of the lattice distortion, the band gap energy and the mobility on the carrier concentration. 相似文献
86.
The influence of substrate temperature on the structural, electrical, and optical properties of aluminum-doped zinc oxide (AZO) films fabricated by radio frequency (RF) magnetron sputtering was investigated. The AZO films were deposited at various substrate temperatures, and the effect of AZO gate electrode conductivity on organic thin film transistor (OTFT) performance was examined. While an increase in the substrate temperature from 100 °C to 300 °C led to an improvement in crystallinity, substrate temperatures over 300 °C caused degradation of the electrical and surface properties. We fabricated OTFTs using AZO films prepared at various substrate temperatures and obtained good device performance. Thus, the performance of an OTFT can be determined by the conductivity of the AZO gate electrode. 相似文献
87.
P K Khare S K Paliwal R Kuraria H L Vishwakarma Ashish Verma S K Jain 《Bulletin of Materials Science》1998,21(2):139-147
A detailed study of electrical conduction mechanism in bimetallized ferrocene-doped polyvinyl pyrrolidone films was carried
out. The measurements were carried out on films of about 20 μm thick, in the field range of (2.0–8.0) x 104 V/cm at temperatures ranging from 363 to 423 K. An investigation of the effect of impurity such as ferrocene in the polymer
matrix was undertaken. Lowering of activation energy and increase in current due to doping were observed. The results showed
that the charge carriers were generated by field-assisted lowering of coulombic barriers at the traps and were conducted through
the bulk of the material by a hopping process between the localized states by a Jonscher-Ansari modified Poole-Frenkel mechanism.
The dependence of current and activation energy on the ferrocene concentration is explained on the basis of charge transfer
type of interaction between dopant and polymeric material. 相似文献
88.
Jiaxiong XuRuohe Yao 《Thin solid films》2011,520(1):515-518
Boron-doped or phosphorus-doped β-FeSi2 thin films have been prepared on silicon substrate by magnetron sputtering. Effects of Si/Fe ratio on the boron and phosphorus doping efficiencies have been studied from the resistivities of doped β-FeSi2 thin films and current-voltage characteristics of doped β-FeSi2/Si heterojunctions. The experimental results reveal that the carrier concentration and doping efficiency of boron or phosphorus dopants at the Fe-rich side are higher than that at the Si-rich side. The effect of Si/Fe ratio can be deduced from the comparison of the formation energies under two extreme conditions. At the Fe-rich limit condition, the formation energy of boron or phosphorous doping is lower than that at the Si-rich condition. Therefore, the activation of impurities is more effective at the Fe-rich side. These results demonstrate that the boron-doped and phosphorous-doped β-FeSi2 thin films should be kept at the Fe-rich side to avoid the unexpected doping sites and low doping efficiency. 相似文献
89.
Silver nanoparticles with a mean diameter of approximately 30 nm were synthesized by reduction of silver nitrate with triethanolamine in the presence of polyacrylic acid. Silver nanoparticle-based ink was prepared by dispersing silver nanoparticles into a mixture of water and ethylene glycol. The mechanism for the dispersion and aggregation of silver nanoparticles in ink is discussed. The strong electrostatic repulsions of the carboxylate anions of the adsorbed polyacrylic acid molecules disturbed the aggregation of metal particles in solutions with a high pH value (pH > 5). An inkjet printer was used to deposit this silver nanoparticle-based ink to form silver patterns on photo paper. The actual printing qualities of the silver tracks were then analyzed by variation of printing passes, sintering temperature and time. The results showed that sintering temperature and time are associated strongly with the conductivity of the inkjet-printed conductive patterns. The conductivity of printed patterns sintered at 150 °C increased to 2.1 × 107 S m−1, which was approximately one third that of bulk silver. In addition, silver tracks on paper substrate also showed better electrical performance after folding. This study demonstrated that the resulting ink-jet printed patterns can be used as conductive tracks in flexible electronic devices. 相似文献
90.
Sheikh M. Uddin Tanvir Mahmud Christoph Wolf Carsten Glanz Ivica Kolaric Christoph Volkmer Helmut Höller Ulrich Wienecke Siegmar Roth Hans-Jörg Fecht 《Composites Science and Technology》2010
Utilizing the extra-ordinary properties of carbon nanotube (CNT) in metal matrix composite (MMC) for macroscopic applications is still a big challenge for science and technology. Very few successful attempts have been made for commercial applications due to the difficulties incorporating CNTs in metals with up-scalable processes. CNT reinforced copper and copper alloy (bronze) composites have been fabricated by well-established hot-press sintering method of powder metallurgy. The parameters of CNT–metal powder mixing and hot-press sintering have been optimized and the matrix materials of the mixed powders and composites have been evaluated. However, the effect of shape and size of metal particles as well as selection of carbon nanotubes has significant influence on the mechanical and electrical properties of the composites. The hardness of copper matrix composite has improved up to 47% compared to that of pure copper, while the electrical conductivity of bronze composite has improved up to 20% compared to that of the pure alloy. Thus carbon nanotube can improve the mechanical properties of highly-conductive low-strength copper metals, whereas in low-conductivity high-strength copper alloys the electrical conductivity can be improved. 相似文献