共查询到19条相似文献,搜索用时 125 毫秒
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采用磁控溅射技术在SnO2薄膜表面修饰金属Ni,研究Ni修饰量对SnO2薄膜气敏性能影响。对Ni-SnO2薄膜进行表面成分分析,发现Ni的表面含量和化学价态对Ni-SnO2薄膜气敏性能影响至关重要。Ni的表面修饰量在3.4%-8.8%之间将有效提高SnO2薄膜对低浓度氢气的敏感性能。180℃工作温度下,表面含Ni3.4%的SnO2薄膜对1000ppm的氢气灵敏度最高为59.6,同时响应时间和恢复时间降低至15s和125s。Ni修饰量增加到23.4%,薄膜的气敏性能恶化,这是因为修饰层过厚,阻碍气体与SnO2材料接触。同时,XPS证实NiO是增加SnO2薄膜气敏性能的主要物质,增敏机理解释为Ni氧化后形成的NiO在SnO2薄膜上形成p-n结,促进元件的电导变化,从而提高了薄膜的气敏性能。 相似文献
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制备了SnO3/ZnO及ZnO/SnO3多层结构的气敏薄膜,用能谱结合氩离子刻蚀的方法及X射线衍射法,对薄膜的表面吸附。膜间的相互与组成等进行了研究,结果表明:薄膜表面存在少量的吸附多层膜中锌的扩散远比锡一个模型,对吸附现象作了初步的解释,讨论了造成锌锡扩散的原因。 相似文献
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SnO_2复合薄膜甲烷气敏传感器研究进展 总被引:5,自引:4,他引:1
甲烷是具有稳定四面体分子结构的碳氢化合物,其键能大、分解困难且活性低,是煤矿安全生产的主要障碍及一种温室气体。SnO2半导体薄膜制备工艺简单、成本低廉、性能稳定,是甲烷传感器研发的主流气敏材料。科技人员进行了很多相关研究以提高传感器的性能,如新气敏材料的研究、催化剂/添加剂的使用、气敏机理的探索、传感器结构改进及气敏膜的表面修饰改性等。本文从气敏膜制备与改性、传感器结构设计及气敏机理研究三个方面,综述了近年来SnO2复合薄膜甲烷传感器的研究进展,结果表明:①应开发复合型金属氧化物半导体及高分子气敏材料,以提高灵敏度、选择性与稳定性;②研发微型智能传感器是未来发展的主要方向,而自组装技术应可用于制备金属氧化物半导体薄膜气体传感器微纳阵列;③气敏机理应与实验测试、材料设计及器件制备进行对照研究。 相似文献
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Sven Sängerlaub Doris Gibis Eva Kirchhoff Melanie Tittjung Markus Schmid Kajetan Müller 《Packaging Technology and Science》2013,26(1):17-30
To protect sensitive food products from oxidative deterioration, multilayer barrier film systems and also modified atmosphere packaging are widely applied. However, the preservation of food quality in such packaging systems may be compromised by the presence of defects in the sealing layer of the films, especially when these are below a critical size, typically the detection limit of standard leak testers of 10 µm. The addition of an oxygen scavenger (OS) layer in barrier film structures could therefore provide extended protection against O2 penetration through such defects. In this study, O2 absorption of different multilayer film structures including an iron‐based OS were investigated under defined gas atmospheres. Measurement cells were thereby covered with plastic films of defined O2 permeability to simulate conditions in a food package during storage with pinhole defect sizes of 10 and 17 µm. The results indicated that the OS film structures applied could only compensate for a defect size of 10 µm in the sealing layer. Analysis of the O2 absorption of different multilayer film structures at 85% and 100% relative humidity showed that higher humidity accelerates the activation of the scavenger. After full activation, the scavenger kinetics are the same for 85% and 100% relative humidity. Long‐term storage experiments using the most effective film structure from the preliminary experiments were carried out to compare O2 absorption of a snack food product in packages with and without an OS. The analyzed linear gradient of the reaction of the OS film and food product, respectively, indicated first‐order reaction kinetics with corresponding reaction constants calculated to be K (food product) 0.021 mg (O2) mbar (O2)?1 day?1 and K (OS film) 0.066 mg (O2) mbar (O2)?1 day?1. The reaction velocity of the OS was thus three times faster than that of the food. The applicability of OS multilayer film systems to compensate a critical pinhole defect size of 10 µm for sensitive food products could therefore be confirmed. The measurement of quality parameters for the status of lipid oxidation processes would help to verify this result. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Charinee Winotapun Supanut Phattarateera Ajcharaporn Aontee Nantaya Junsook Witchuda Daud Noppadon Kerddonfag Wannee Chinsirikul 《Packaging Technology and Science》2019,32(8):405-418
The symmetrical A/B/A structure of multilayer blown films was fabricated in this study. The immiscible low‐density polyethylene/polylactic acid (LDPE/PLA) blend was set as a core (B) layer and LDPE was used as skin (A) layers. The compositions of PLA in the core layer were varied from 20 to 50 wt%. The thickness of each layer was 10 μm (total film thickness of ~ 30 μm). In a blown film co‐extrusion process, the morphology of the fiber/ribbon‐like structures of LDPE/PLA blend was developed. Such structures had interesting effects on gas permeability and aroma barrier properties of the films. For instance, multilayer LDPE films containing 40 and 50 wt% PLA (P40 and P50) showed the reduction of oxygen permeability (PO2) approximately 20% and 43%, respectively, compared with the neat LDPE film. A long tortuous path for gas and aroma transportation through film thickness was created from the developed ribbon‐like structures of the PLA minor phase. For durian packaging application, fresh‐cut durian of 300 g was packed in the developed multilayer films, LDPE, and HDPE (Control), stored at 4°C for 7 days. Results demonstrated that the steady‐state condition of 10% to 13% O2 and 8% to 10% CO2 was achieved in all packages except in the HDPE. Moreover, the P40 and P50 films exhibited an outstanding aroma barrier property for three major durian volatiles : diethyl sulfide, ethyl propanoate, and 2‐ethyl‐1‐hexanol. Overall results clearly indicated that the multilayer LDPE films containing PLA exhibited a significantly improved aroma barrier performance with optimum gas permeability desirable for modified atmosphere packaging to retain quality of fresh‐cut durian throughout the storage period. 相似文献
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Kim HJ Kim KC Choi WC Kim JS Kim YH Kim SI Park C 《Journal of nanoscience and nanotechnology》2012,12(4):3629-3632
A bismuth telluride (BT)/indium selenide (IS) multilayer film was deposited at room temperature by rf magnetron sputtering on a sapphire substrate in order to investigate how the multilayered structure affects the microstructure and thermoelectric properties. The effect of annealing at different temperatures was also studied. The results were compared with those from a BT film with the same thickness. A TEM study showed that the interface between the BT and IS layers became vague as the annealing temperature increased, and the BT layer crystallized while the IS layer did not. The presence of thin IS layers can help to limit the evaporation of Te from the BT/IS multilayer film, thus increasing the amount of Bi2Te3 phase in the multilayer film as compared with that of the BT film. An abrupt increase in the Seebeck coefficient of the multilayer film was observed when annealed at 300 degrees C, and the resistivity of the annealed multilayer film was high compared to that of the BT film. This result can also be explained by the proposed role of the IS layer, which limits the evaporation of Te at high temperature. The highest power factor of -3.9 x 10(-6) W/K2 cm was obtained at room temperature from the multilayer film annealed at 300 degrees C. 相似文献
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D. Dutta E. Bontempi Y. You S. Sinha J. Das S. K. Hazra C. K. Sarkar S. Basu 《Journal of Materials Science: Materials in Electronics》2017,28(1):157-166
Atmospheric pressure chemical vapour deposition was employed to deposit graphene thin films on thermally oxidized p-silicon substrates. Raman spectroscopy and energy dispersive spectroscopy revealed the multilayer nature and the composition of the grown graphene films respectively. The defective nature and the defect density of the graphene films were determined from the Raman experiments. Field effect scanning electron microscopy, transmission electron microscopy and atomic force microscopy were used to study the surface morphology of the multilayer graphene films. The film topography was sensitive to temperature and time of growth. A suitable growth mechanism has been proposed to explain the topographical observations. The large surface area of the multilayer films was found to be suitable for hydrogen sensor applications and the sensing results were correlated with the morphology of the grown films. 相似文献
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磁性研究是个古老而又暂新的课题,目前,随着信息产业的发展,磁性多层膜领域的研究正在引起人们更多的重视,综述了磁性多层膜领域的若干进展,认为该领域的研究主要集中在多磁性多层膜的结构研究,磁学特性的研究以及多层膜理论计算领域等几个方面。 相似文献
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介质/金属/介质多层透明导电薄膜研究进展 总被引:3,自引:1,他引:2
综述了介质/金属/介质(dielectric/metal/dielectric,D/M/D)多层透明导电膜材料的特点、制备方法、研究进展与应用现状,重点比较讨论了ITO/Ag/ITO、ZnS/Ag/ZnS的膜系结构、光电性能、化学稳定性、热稳定性等特点,以及与国内外的研究差距.ITO/Ag/ITO、ZnS/Ag/ZnS是目前光电性能最好,且无需引入过渡层的两种D/M/D膜系,但有关其热稳定性的评价和研究存在不同的观点.用资源丰富、价格便宜、无毒的掺铝氧化锌(ZAO)薄膜取代含有价格昂贵的贵金属铟的掺锡氧化铟(ITO)薄膜,ZAO/Ag/ZAO膜系结构的设计、薄膜制备、光电性能与IMI的对比研究是目前国内外D/M/D研究中的热点课题和D/M/D发展的主要方向. 相似文献
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A new system to obtain ultrathin self-standing polyelectrolyte multilayer membranes at physiological conditions is introduced. On the surface of a substrate, a hybrid film structure composed of two compartments, (1) a pH-responsive film segment formed via hydrogen bonds and (2) a polyelectrolyte multilayer film on top of 1, was assembled. The pH-responsive polymer multilayer segments disintegrate at a neutral pH and release self-standing polyelectrolyte multilayer films. The obtained self-supporting polyelectrolyte multilayer membranes had thicknesses of 55 to several hundred nanometers and areas of a few square centimeters, approximately. The preparation method introduced here avoids harsh release conditions and thus broadens the choice of materials that can be incorporated into the self-standing film. 相似文献