共查询到20条相似文献，搜索用时 46 毫秒
1.
Misewich JA Martel R Avouris P Tsang JC Heinze S Tersoff J 《Science (New York, N.Y.)》2003,300(5620):783-786
Polarized infrared optical emission was observed from a carbon nanotube ambipolar field-effect transistor (FET). An effective forward-biased p-n junction, without chemical dopants, was created in the nanotube by appropriately biasing the nanotube device. Electrical measurements show that the observed optical emission originates from radiative recombination of electrons and holes that are simultaneously injected into the undoped nanotube. These observations are consistent with a nanotube FET model in which thin Schottky barriers form at the source and drain contacts. This arrangement is a novel optical recombination radiation source in which the electrons and holes are injected into a nearly field-free region. Sucha source may form the basis for ultrasmall integrated photonic devices. 相似文献
2.
The development of strategies for addressing arrays of nanoscale devices is central to the implementation of integrated nanosystems such as biological sensor arrays and nanocomputers. We report a general approach for addressing based on molecular-level modification of crossed semiconductor nanowire field-effect transistor (cNW-FET) arrays, where selective chemical modification of cross points in the arrays enables NW inputs to turn specific FET array elements on and off. The chemically modified cNW-FET arrays function as decoder circuits, exhibit gain, and allow multiplexing and demultiplexing of information. These results provide a step toward the realization of addressable integrated nanosystems in which signals are restored at the nanoscale. 相似文献
3.
Organic field-effect transistors have been developed that function as either n-channel or p-channel devices, depending on the gate bias. The two active materials are alpha-hexathienylene (alpha-6T) and C(60). The characteristics of these devices depend mainly on the molecular orbital energy levels and transport properties of alpha-6T and C(60). The observed effects are not unique to the two materials chosen and can be quite universal provided certain conditions are met. The device can be used as a building block to form low-cost, low-power complementary integrated circuits. 相似文献
4.
A field-effect transistor has been fabricated from polymer materials by printing techniques. The device characteristics, which show high current output, are insensitive to mechanical treatments such as bending or twisting. This all-organic flexible device, realized with mild techniques, opens the way for large-area, low-cost plastic electronics. 相似文献
5.
We report here on a novel realization of a field-effect device that allows switching between insulating and superconducting states, which is the widest possible variation of electrical properties of a material. We chose C(60) as the active material because of its low surface state density and observed superconductivity in alkali metal-doped C(60). We induced three electrons per C(60) molecule in the topmost molecular layer of a crystal with the field-effect device, creating a superconducting switch operating up to 11 kelvin. An insulator was thereby transformed into a superconductor. This technique offers new opportunities for the study of superconductivity as a function of carrier concentration. 相似文献
6.
The manufacture of high-performance, conjugated polymer transistor circuits on flexible plastic substrates requires patterning techniques that are capable of defining critical features with submicrometer resolution. We used solid-state embossing to produce polymer field-effect transistors with submicrometer critical features in planar and vertical configurations. Embossing is used for the controlled microcutting of vertical sidewalls into polymer multilayer structures without smearing. Vertical-channel polymer field-effect transistors on flexible poly(ethylene terephthalate) substrates were fabricated, in which the critical channel length of 0.7 to 0.9 micrometers was defined by the thickness of a spin-coated insulator layer. Gate electrodes were self-aligned to minimize overlap capacitance by inkjet printing that used the embossed grooves to define a surface-energy pattern. 相似文献
7.
A microfluidic device has been developed that can adsorb proteins from solution, hold them with negligible denaturation, and release them on command. The active element in the device is a 4-nanometer-thick polymer film that can be thermally switched between an antifouling hydrophilic state and a protein-adsorbing state that is more hydrophobic. This active polymer has been integrated into a microfluidic hot plate that can be programmed to adsorb and desorb protein monolayers in less than 1 second. The rapid response characteristics of the device can be manipulated for proteomic functions, including preconcentration and separation of soluble proteins on an integrated fluidics chip. 相似文献
8.
Thin-film transistor fabricated in single-crystalline transparent oxide semiconductor 总被引：1，自引：0，他引：1
Nomura K Ohta H Ueda K Kamiya T Hirano M Hosono H 《Science (New York, N.Y.)》2003,300(5623):1269-1272
We report the fabrication of transparent field-effect transistors using a single-crystalline thin-film transparent oxide semiconductor, InGaO3(ZnO)5, as an electron channel and amorphous hafnium oxide as a gate insulator. The device exhibits an on-to-off current ratio of approximately 106 and a field-effect mobility of approximately 80 square centimeters per volt per second at room temperature, with operation insensitive to visible light irradiation. The result provides a step toward the realization of transparent electronics for next-generation optoelectronics. 相似文献
9.
根据功率LED的柔性封装要求,提出了基于贴片式(SMD)封装的功率型LED柔性封装结构。对各层结构进行了优化设计,采用有限元分析(FEA),模拟了柔性封装结构LED的热场分布。对比研究了柔性LED与传统封装结构LED的热特性,并对弯曲状态下柔性衬底材料对芯片的应力进行了分析。结果表明,采用金属Cu箔衬底的柔性封装结构,其散热特性较好;Cu/超薄玻璃复合衬底替代Cu箔衬底,可以减少弯曲的应力,减少幅度达到2.5倍,散热特性基本相同。SMD柔性封装的LED不仅具有较好的热稳定性,且具有柔性可挠曲特性,其应用潜力很大。 相似文献
10.
LED光源在现代农业的应用原理与技术进展 总被引：6，自引：0，他引：6
随着LED技术的发展和制造成本的下降,LED光源在现代农业中的应用越来越受到世界各国的广泛关注。LED不仅具有体积小、寿命长、能耗低、发光效率高、发热低等光电特性优点,而且还能根据农业生物的需要进行光谱的精确配置,促进农业生物的生长发育和光形态建成,从而提高其产量和品质。本文介绍了LED在农业照明领域的应用现状,分析了LED在农业领域的应用潜力,指出了限制农用LED推广应用的关键因素,并提出促进LED在现代农业中应用的发展思路、方向和重点以及对策。 相似文献
11.
Lin YM Valdes-Garcia A Han SJ Farmer DB Meric I Sun Y Wu Y Dimitrakopoulos C Grill A Avouris P Jenkins KA 《Science (New York, N.Y.)》2011,332(6035):1294-1297
A wafer-scale graphene circuit was demonstrated in which all circuit components, including graphene field-effect transistor and inductors, were monolithically integrated on a single silicon carbide wafer. The integrated circuit operates as a broadband radio-frequency mixer at frequencies up to 10 gigahertz. These graphene circuits exhibit outstanding thermal stability with little reduction in performance (less than 1 decibel) between 300 and 400 kelvin. These results open up possibilities of achieving practical graphene technology with more complex functionality and performance. 相似文献
12.
介绍了一种船舶航海综合报警器的设计。该报警器设计中,采用高速单片机为核心,将船舶上各种其他报警设备产生的报警信号高速扫描读入后进行综合,使用组合式LED指示灯对综合后的报警信号进行复示,并用蜂鸣器进行声音报警。由于采用了单片机为核心,该报警器反应迅速、性能可靠;采用了组合式LED的设计,使该报警器有很好的灵活性和通用性。 相似文献
13.
The thiophene oligomer alpha-hexathienylene (alpha-6T) has been successfully used as the active semiconducting material in thin-film transistors. Field-induced conductivity in thin-film transistors with alpha-6T active layers occurs only near the interfacial plane, whereas the residual conductivity caused by unintentional doping scales with the thickness of the layer. The two-dimensional nature of the field-induced conductivity is due not to any anisotropy in transport with respect to any molecular axis but to interface effects. Optimized methods of device fabrication have resulted in high field-effect mobilities and on/off current ratios of > 10(6). The current densities and switching speeds are good enough to allow consideration of these devices in practical large-area electronic circuits. 相似文献
14.
15.
To find use in electronics, single-walled carbon nanotubes need to be efficiently separated by electronic type and aligned to ensure optimal and reproducible electronic properties. We report the fabrication of single-walled carbon nanotube (SWNT) network field-effect transistors, deposited from solution, possessing controllable topology and an on/off ratio as high as 900,000. The spin-assisted alignment and density of the SWNTs are tuned by different surfaces that effectively vary the degree of interaction with surface functionalities in the device channel. This leads to a self-sorted SWNT network in which nanotube chirality separation and simultaneous control of density and alignment occur in one step during device fabrication. Micro-Raman experiments corroborate device results as a function of surface chemistry, indicating enrichment of the specific SWNT electronic type absorbed onto the modified dielectric. 相似文献
16.
太阳能LED特征光谱害虫诱杀器 总被引：2，自引：0，他引：2
根据17种农林业主要害虫的趋光特性及敏感波长范围,以特征光谱LED害虫诱杀灯为核心,设计太阳能LED特征光谱害虫诱杀器.提出害虫趋光性具有特征光谱的概念,并阐述了昆虫反应阈值光谱的研究方法. 相似文献
17.
为探究不同LED光质对辣椒采后果实品质的影响,以黑暗处理为对照,采用LED白光、红光和蓝光分别对辣椒(Capsicum annum L.)P1833的采后果实进行处理,并对果实质量和硬度、辣椒素类物质、维生素C、氨基酸含量等商品性和风味营养指标进行了测定和比较分析。结果表明,与对照相比,LED白光处理可显著降低辣椒果实中的辣椒素类物质含量,提高叶绿素含量(P<0.05);LED红光处理的辣椒果实质量和硬度与对照相比无显著差异,蛋白质和维生素C含量显著高于对照(P<0.05);LED蓝光处理果实辣椒素类物质含量显著低于对照,显著高于LED白光和红光处理,维生素C含量显著高于对照和白光处理(P<0.05)。此外,LED蓝光处理辣椒果实中的总氨基酸、人体必需氨基酸、儿童必需氨基酸、鲜味氨基酸含量均达到或接近对照的2倍,且人体必需氨基酸营养价值质量分数明显高于对照和其他光质处理。综上,LED白光能够延缓辣椒果实褪绿,LED红光可保持果实商品性,LED蓝光在增加果实氨基酸营养价值方面具有重要调控作用。 相似文献
18.
探讨不同LED光色对兔行为及同期发情影响的分子机制。行为学观察在6 m×6 m正方形漏缝木地板平台上进行,四周用敞门兔笼合围,每边6个兔笼,笼内均匀放置常规乳头式饮水器及料槽,兔笼上方60 cm处分别安装LED灯带,向下投射LED红光(660 nm)、绿光(540 nm)、蓝光(480 nm)和白光(400~760 nm),光照强度均100 lx,时长为12 D:12 L,每周随机调整1次LED灯带位置,确保LED光色成为唯一变量,摄像头记录并统计母兔选择性停留行为。LED光色试验是将不同LED光色下300只单笼饲养的后备母兔随机平均分成5组,每组3个重复,每个重复20只。兔笼上方60 cm处向下投射LED红光(660 nm)、LED绿光(540 nm)、LED蓝光(480 nm)和LED白光(400~760 nm),对照组为白炽灯(400~1 050 nm)。正式试验中,每周五至周日18:00至次日06:00,时长为12 h,光照强度均为100 lx,预试期7 d,正试期90 d。结果显示:不同LED光色能够影响母兔活动空间的选择,LED红光环境更易被母兔接受并停留,其停留频率分别比LED绿光与LED蓝光高13.1%和11.6%,差异显著(P<0.05)。LED红色光及白炽灯组后备青年母兔血清中的β-内啡肽、5-羟色胺浓度显著(P<0.05)高于LED绿光组及LED蓝光组;LED红光环境中皮质醇浓度显著(P<0.05)高于LED绿光组。LED红光组母兔同期发情率与白炽灯对照组及LED白光组相比,分别提高20.89%和10.51%,差异显著(P<0.05)。LED红光组母兔视网膜内Opn4基因表达量显著高于白炽灯组和LED绿光组(P<0.05)。不同LED光色对特定时间段(23:30至次日00:30)母兔血清MLT含量有影响。与LED绿光组相比,LED红光组环境中母兔血清MLT含量低10.32%,差异显著(P<0.05)。与LED白光相比,LED红光能显著(P<0.05)抑制松果体内Aanat mRNA的表达(P<0.05)。LED红光组母兔松果体中Mel1a mRNA表达量显著高于LED绿光组和蓝光组(P<0.05)。总之,规模兔场短日照季节周期化繁殖生产中,每周连续3 d于晚间18:00至次日凌晨6:00之间,采用100 lx LED红光进行补光,可提高母兔同期发情率,LED红光能够通过视网膜-松果体路径对兔行为及同期发情产生影响。 相似文献
19.
不同LED补光光源对樱桃番茄产量和品质的影响 总被引：5，自引：0，他引：5
为研究LED 补光对温室樱桃番茄产量和品质的影响,探讨设施栽培中利用补光手段实现增产和提高品质的调控新途径,以哈金龙樱桃番茄为试验材料,在温室条件下采用LED灯带和LED灯管对定植后樱桃番茄进行侧面补光,光源光通量密度为100μmol/m²·s,每天补光12 h (8:00~20:00),测定分析不同补光处理下樱桃番茄果实产量和品质的变化。结果表明,LED灯管和LED灯带补光处理的樱桃番茄挂果数、总产量和单果重均显著高于对照,且LED灯管处理效果较好,挂果数、总产量和单果重分别提高48.91%、94.86%和30.86%。LED 灯管补光处理能显著提高樱桃番茄果实的品质指标,VC、可溶性蛋白、游离氨基酸、可溶性糖和蔗糖含量均显著高于对照,番茄红素,花色苷、类黄酮和可溶性酚含量均最高,番茄着色最好。 相似文献
20.
LED具有高效、节能、环保、寿命长、响应速度快等特点,被视作必将成为继白炽灯、荧光灯、高强度气体放电灯之后的第四代光源.但目前LED芯片80%～90%的电能转化成热量,而仅靠芯片封装器件外壳散热难以维持低温情况,严重制约了大功率LED灯的应用.主要研究在自然空气冷却状态下,影响大功率LED灯散热性能的因素及各因素影响的... 相似文献