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Laser-based micro/nanofabrication in one, two and three dimensions
Wei XIONG,Yunshen ZHOU,Wenjia HOU,Lijia JIANG,Masoud MAHJOURI-SAMANI,Jongbok PARK,Xiangnan HE,Yang GAO,Lisha FAN,Tommaso BALDACCHINI,Jean-Francois SILVAIN,Yongfeng LU
Front. Optoelectron.. 2015, 8 (4): 351-378.
https://doi.org/10.1007/s12200-015-0481-3
Advanced micro/nanofabrication of functional materials and structures with various dimensions represents a key research topic in modern nanoscience and technology and becomes critically important for numerous emerging technologies such as nanoelectronics, nanophotonics and micro/nanoelectromechanical systems. This review systematically explores the non-conventional material processing approaches in fabricating nanomaterials and micro/nanostructures of various dimensions which are challenging to be fabricated via conventional approaches. Research efforts are focused on laser-based techniques for the growth and fabrication of one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) nanomaterials and micro/nanostructures. The following research topics are covered, including: 1) laser-assisted chemical vapor deposition (CVD) for highly efficient growth and integration of 1D nanomaterial of carbon nanotubes (CNTs), 2) laser direct writing (LDW) of graphene ribbons under ambient conditions, and 3) LDW of 3D micro/nanostructures via additive and subtractive processes. Comparing with the conventional fabrication methods, the laser-based methods exhibit several unique advantages in the micro/nanofabrication of advanced functional materials and structures. For the 1D CNT growth, the laser-assisted CVD process can realize both rapid material synthesis and tight control of growth location and orientation of CNTs due to the highly intense energy delivery and laser-induced optical near-field effects. For the 2D graphene synthesis and patterning, room-temperature and open-air fabrication of large-scale graphene patterns on dielectric surface has been successfully realized by a LDW process. For the 3D micro/nanofabrication, the combination of additive two-photon polymerization (TPP) and subtractive multi-photon ablation (MPA) processes enables the fabrication of arbitrary complex 3D micro/nanostructures which are challenging for conventional fabrication methods. Considering the numerous unique advantages of laser-based techniques, the laser-based micro/nanofabrication is expected to play a more and more important role in the fabrication of advanced functional micro/nano-devices.
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Optical approaches in study of nanocatalysis with single-molecule and single-particle resolution
Kun LI,Weiwei QIN,Yan XU,Tianhuan PENG,Di LI
Front. Optoelectron.. 2015, 8 (4): 379-393.
https://doi.org/10.1007/s12200-014-0423-5
Studying the activity of individual nanocatalysts, especially with high spatiotemporal resolution of single-molecule and single-turnover scale, is essential for the understanding of catalytic mechanism and the designing of effective catalysts. Several approaches have been developed to monitor the catalytic reaction on single catalysts. In this review, we summarized the updated progresses of several new spectroscopic and microscopic approaches, including single-molecule fluorescence microscopy, surface-enhanced Raman spectroscopy, surface plasmon resonance microscopy and X-ray microscopy, for the study of single-molecule and single-particle catalysis.
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Transmission of 200 Tb/s (375 × 3 × 178.125 Gb/s) PDM-DFTS-OFDM-32QAM super channel over 1 km FMF
Ming LUO,Qi MO,Xiang LI,Rong HU,Ying QIU,Cai LI,Zhijian LIU,Wu LIU,Huang YU,Wei DU,Jing XU,Zhixue HE,Qi YANG,Shaohua YU
Front. Optoelectron.. 2015, 8 (4): 394-401.
https://doi.org/10.1007/s12200-015-0555-2
A few-mode fiber (FMF) is designed to support three spatial modes (LP01, LP11a, and LP11b) and fabricated through plasma chemical vapor deposition (PCVD)and rod-in-tube (RIT) method. Using PDM-DFTS-OFDM-32QAM modulation, wavelength division multiplexing, mode multiplexing, and coherent detection, we successfully demonstrated 200 Tb/s (375 × 3 × 178.125 Gb/s) signal over 1 km FMF using C and L bands with 25 GHz channel spacing. After 1 km FMF transmission, all the tested bit error rates (BERs) are below 20% forward error correction (FEC) threshold (2.0 × 10−2). Within each sub-channel, we achieved a spectral efficiency of 21.375 bits/Hz in the C and L bands.
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An improved noise reduction algorithm based on wavelet transformation for MEMS gyroscope
Jianguo YUAN,Yantao YUAN,Feilong LIU,Yu PANG,Jinzhao LIN
Front. Optoelectron.. 2015, 8 (4): 413-418.
https://doi.org/10.1007/s12200-015-0474-2
To solve the large noise problem for the low-precision gyroscopes in micro-electro mechanical systems (MEMS) of inertial navigation system, an improved noise reduction method, based on the analyses of the fast Fourier transformation (FFT) noise reduction principle and the simple wavelet noise reduction principle, was proposed. Furthermore, the FFT noise reduction method, the simple wavelet noise reduction method and the improved noise reduction method were comparatively analyzed and experimentally verified in the case of the constant rate and dynamic rate. The experimental analysis results showed that the improved noise reduction method had a very good result in the noise reduction of the gyroscope data at different frequencies, and its performance was superior to those of the FFT noise reduction method and the simple wavelet noise reduction method.
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Fiber up-taper assisted Mach-Zehnder interferometer for high sensitive temperature sensing
Lili MAO,Qizhen SUN,Ping LU,Zefeng LAO,Deming LIU
Front. Optoelectron.. 2015, 8 (4): 431-438.
https://doi.org/10.1007/s12200-014-0455-x
A new in-line Mach-Zehnder interferometer (MZI) sensor consisting of a stub of multi-mode fiber and an up-taper was proposed and demonstrated. Temperature measurement can be carried out by detecting wavelength shift. Dependency of sensitivity on interferometer length and dip wavelength was discussed. Experimental results showed a maximum temperature sensitivity of 113.6 pm/°C can be achieved, which is superior to most fiber temperature sensors based on in-line MZIs within the range from 20°C to 80°C, also a good mechanical strength can be obtained. The proposed sensor is a good candidate for temperature measurement, due to the advantages of simple structure, easy fabrication, cost-effective and high sensitivity.
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High efficiency yellow fluorescent organic light emitting diodes based on m-MTDATA/BPhen exciplex
Liping ZHU,Kai XU,Yanping WANG,Jiangshan CHEN,Dongge MA
Front. Optoelectron.. 2015, 8 (4): 439-444.
https://doi.org/10.1007/s12200-015-0492-0
High efficient yellow organic light emitting diodes (OLEDs) based on exciplex were reported. The exciplex was formed by 4, 4′, 4′′-tris [3-methylphenyl (phenyl) amino]-triphenylamine (m-MTDATA) and 4, 7-diphenyl-1, 10-phenanthroline (BPhen). The resulting yellow OLEDs exhibited an external quantum efficiency of over 7%, which is attributed to the effective energy back transfer from exciplex triplet state to exciplex singlet state. The maximum power efficiency of 25 lm/W was achieved. Doping a yellow phosphor Ir(bt)2(acac) into m-MTDATA:BPhen blend, a high efficiency device was achieved with a turn-on voltage of 2.1 V, maximum power efficiency and external quantum efficiency of 86.1 lm/W and 20.7%, respectively.
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Simulation study on the active layer thickness and the interface of a-IGZO-TFT with double active layers
Xiaoyue LI,Sheng YIN,Dong XU
Front. Optoelectron.. 2015, 8 (4): 445-450.
https://doi.org/10.1007/s12200-014-0451-1
In this paper, ATLAS 2D device simulator of SILVACO was used for device simulation of inverted-staggered thin film transistor using amorphous indium gallium zinc oxide as active layer (a-IGZO-TFT) with double active layers, based on the density of states (DOS) model of amorphous material. The change of device performance induced by the thickness variation of each active layer was studied, and the interface between double active layers was analyzed. The best performance was found when the interface was near the edge of the channel, by optimizing the thickness of each active layers, the high performance device of threshold voltage (Vth) = −0.89 V, sub-threshold swing (SS)= 0.27, on/off current ratio (ION/IOFF) = 6.98 × 1014 was obtained.
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13 articles
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