全文获取类型
收费全文 | 424篇 |
免费 | 61篇 |
国内免费 | 103篇 |
专业分类
电工技术 | 7篇 |
综合类 | 16篇 |
化学工业 | 25篇 |
金属工艺 | 4篇 |
机械仪表 | 10篇 |
矿业工程 | 2篇 |
能源动力 | 3篇 |
轻工业 | 1篇 |
武器工业 | 2篇 |
无线电 | 408篇 |
一般工业技术 | 91篇 |
自动化技术 | 19篇 |
出版年
2024年 | 1篇 |
2023年 | 16篇 |
2022年 | 14篇 |
2021年 | 31篇 |
2020年 | 21篇 |
2019年 | 26篇 |
2018年 | 20篇 |
2017年 | 32篇 |
2016年 | 35篇 |
2015年 | 22篇 |
2014年 | 30篇 |
2013年 | 28篇 |
2012年 | 19篇 |
2011年 | 27篇 |
2010年 | 15篇 |
2009年 | 31篇 |
2008年 | 32篇 |
2007年 | 30篇 |
2006年 | 23篇 |
2005年 | 24篇 |
2004年 | 17篇 |
2003年 | 13篇 |
2002年 | 18篇 |
2001年 | 17篇 |
2000年 | 16篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 9篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 2篇 |
排序方式: 共有588条查询结果,搜索用时 15 毫秒
1.
Zeyu He Jiayue Han Xiaoyang Du Luye Cao Jun Wang Caijun Zheng Hui Lin Silu Tao 《Advanced functional materials》2021,31(37):2103988
Emerging graphene/organic phototransistors are eye-catching technologies owing to their unique merits including easy/low-cost fabrication, temperature independent, and achieving various functions. However, their development in the near-infrared (NIR) region is experiencing a bottleneck of inferior sensitivity due to low exciton dissociation efficiency and inefficient charge extraction rate. Here, a novel-design solution-processed graphene/organic NIR phototransistor is reported, that is, creatively introducing electron extraction layer of ZnO on graphene channel and employing organic ternary bulk heterojunction as photosensitive layer, successfully breaking that bottleneck. The phototransistor exhibits a high responsivity of 6.1 × 106 A W−1, a superior detectivity of 2.4 × 1013 Jones, and a remarkable minimum detection power of 1.75 nW cm−2 under 850 nm radiation. Considering its excellent NIR detection performance, a noncontact transmission-type pulse monitoring is carried out with no external circuit support, from which human pulse signal and heart rate can be displayed in real time. The phototransistor, interestingly, can be switched into a photomemory function with a retention time of 1000 s in the atmosphere through a gate voltage of −20 V. The design takes the characteristics of graphene/organic phototransistors to a higher level, beyond the limit of sensitivity, and opens up a novel approach for developing multifunction devices. 相似文献
2.
Ningqin Deng He Tian Jian Zhang Jinming Jian Fan Wu Yang Shen Yi Yang Tian-Ling Ren 《半导体学报》2021,42(8):21-33
Black phosphorus(BP),an emerging two-dimensional material,is considered a promising candidate for next-genera-tion electronic and optoelectronic devices due to in-plane anisotropy,high mobility,and direct bandgap.However,BP devices face challenges due to their limited stability,photo-response speed,and detection range.To enhance BP with powerful electric-al and optical performance,the BP heterostructures can be created.In this review,the state-of-the-art heterostructures and their electrical and optoelectronic applications based on black phosphorus are discussed.Five parts introduce the perform-ance of BP-based devices,including black phosphorus sandwich structure by hBN with better stability and higher mobility,black phosphorus homojunction by dual-gate structure for optical applications,black phosphorus heterojunction with other 2D materials for faster photo-detection,black phosphorus heterojunction integration with 3D bulk material,and BP via As-doping tunable bandgap enabling photo-detection up to 8.2 μm.Finally,we discuss the challenges and prospects for BP electric-al and optical devices and applications. 相似文献
3.
Philipp Sippel Simon Heitz Mikaela Elagin MykhayloP. Semtsiv Rainer Eichberger W. Ted Masselink Thomas Hannappel Klaus Schwarzburg 《Progress in Photovoltaics: Research and Applications》2016,24(3):307-314
We have realized a tandem solar cell design that combines a pin‐junction with a photovoltaic intersubband absorber. This concept allows harvesting light in the visible range and the near‐ and mid‐infrared at the same time, and theoretically, energy conversion efficiencies beyond the Shockley–Queisser‐limit could be achieved. A test structure was grown, and the operation of this concept could be confirmed, in principal with an optical two‐beam experiment. The basic characteristics of the device can be explained with an equivalent circuit design that consists of three individual cells, and we find an obvious analogy to the concept of the intermediate band solar cell with noteworthy advantages at some points. Our results show, that for a working device it is crucial to adjust the properties of the photovoltaic intersubband absorber for optimal charge separating performance at the working point of the solar cell. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
4.
5.
Nacer Debbar 《International Journal of Numerical Modelling》2016,29(2):333-342
We present a numerical characterization of a high‐speed high‐responsivity GaAs lateral Schottky barrier photodiode (LSBPD). The LSBPD is a planar structure composed of interdigitated Schottky barrier and ohmic contacts. A metal–semiconductor–metal (MSM) structure with identical geometry is simulated for comparison. The dark characteristics are found identical for the two devices. Under illumination, the LSBPD exhibited significantly superior responsivity compared with the MSM, while maintaining comparatively similar response time and 3 dB bandwidths. The results of the study indicate conclusively that the lateral Schottky barrier photodiode can provide an excellent alternative to the standard MSM photodetectors for high‐speed optoelectronic applications. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
6.
7.
8.
Undoped and 1 at.% Co-doped ZnO nanostructure based UV photodetectors were successfully fabricated by RF- magnetron sputtering technique with comb like Pt electrodes. Cobalt ions were successfully incorporated into the lattice of the ZnO nanostructure without changing its wurtzite structure. It was indicated that Co-doping can effectively adjust the luminescence properties of the ZnO nanostructure. The undoped and Co-doped ZnO photodetectors were observed to have photosensitivities of 1.44 x 104 % and 8.57 x 102 % and low dark currents of 9.74 x 10-8 A and 1.18 x 10-7 A, respectively. 相似文献
9.
Kimberly Sablon Andrei Sergeev Nizami Vagidov Andrei Antipov John Little Vladimir Mitin 《Nanoscale research letters》2011,6(1):584
We analyze the effect of doping on photoelectron kinetics in quantum dot [QD] structures and find two strong effects of the built-in-dot charge. First, the built-in-dot charge enhances the infrared [IR] transitions in QD structures. This effect significantly increases electron coupling to IR radiation and improves harvesting of the IR power in QD solar cells. Second, the built-in charge creates potential barriers around dots, and these barriers strongly suppress capture processes for photocarriers of the same sign as the built-in-dot charge. The second effect exponentially increases the photoelectron lifetime in unipolar devices, such as IR photodetectors. In bipolar devices, such as solar cells, the solar radiation creates the built-in-dot charge that equates the electron and hole capture rates. By providing additional charge to QDs, the appropriate doping can significantly suppress the capture and recombination processes via QDs. These improvements of IR absorption and photocarrier kinetics radically increase the responsivity of IR photodetectors and photovoltaic efficiency of QD solar cells. 相似文献
10.
单轴压应变量子阱红外探测器吸收波长的研究 总被引:1,自引:0,他引:1
研究了单轴压应力对GaAs/AlGaAs/GaAs量子阱红外探测器(QWIP)吸收波长的影响。以量子阱电子干涉方法以及单轴压应力作用下量子阱应变理论为基础,分析了GaAs/AlGaAs/GaAs量子阱导带中子能级与应变的关系。理论上计算了单轴应力下四个QWIP吸收波长与应变的关系。结果表明,E1与E<1>能级之间的吸收波长和E(1)与EF能级之间的吸收波长随应变的增大而减小的幅度比E1与EF能级之间的吸收波长和E(0)与E1能级之间吸收波长随应变的增大减小的幅度大。 相似文献