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Impact of crystal orientation and surface scattering on DG-MOSFETs in quasi-ballistic region

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Journal of Semiconductors 2018年第7期39卷 67-71页

作者： Lei Shen Shaoyan Di Longxiang Yin Yun Li Xiaoyan Liu Gang Du Institute of Microelectronics Peking University

The characteristics of nano scale n-type double gate MOSFETs with（100） and（110） surfaces are studied using 3 D full band ensemble Monte Carlo simulator. The anisotropic surface scattering mechanism is investigated. The（100） case is sensitive to the gate voltage more than the（110） case. The impact of crystal orientation and surface scattering on transport features mainly reflects in the carrier velocity distribution. The electron transport features with（100） direction are greater than that with（110） direction, but are more likely to be affected by the surface scattering.

关键词： crystal orientation surface scattering quasi-ballistic transport Monte Carlo

Linking Diffractive and Geometrical Optics surface scattering at a Fundamental Level

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Optics and Photonics Journal 2022年第1期12卷 1-17页

作者： Christi Kay Madsen Department of Electrical and Computer Engineering Texas A&M University College Station TX USA

Optical surface scattering analyses based on diffractive optics (DO) are typically applied to one surface;however, there is a need for simulating surface scattering losses for devices having many surface interactions such as light pipes. Light pipes are often simulated with geometric optics (GO) using ray tracing, where surface scattering is driven by the surface slope distribution. In the DO case, surface scattering analyses depend on the spatial frequency distribution and amplitude as well as wavelength, with the sinusoidal grating as a fundamental basis. A better understanding of the link, or transition, between DO and GO scattering domains would be helpful for efficiently incorporating scattering loss analyses into ray trace simulations. A formula for the root-mean-square (rms) scattered angle width of a sinusoidal reflection grating that depends only on the surface rms slope is derived from the nonparaxial scalar diffraction theory, thereby linking it to GO. The scatter angle’s mean and rms width are evaluated over a range of grating amplitudes and periods using scalar theory and full vector simulations from the COMSOL® wave optic module for a sinusoidal reflection grating. The conditions under which the diffraction-based solution closely approximates the GO solution, as predicted by the rms slope, are identified. Close agreement is shown between the DO and GO solutions for the same surface rms slope scattering loss due to angular filtering near the critical angle of a total internal reflection (TIR) glass-to-air interface.

关键词： Diffractive Optics Geometrical Optics Diffraction Gratings surface scattering Light Pipes

Conformation-dependent surface-enhanced Raman scattering of graphene oxide/metal nanoparticle hybrids

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Chinese Optics Letters 2013年第8期11卷 97-99页

作者：刘智明钟会清郭周义杨必文 MOE Key Laboratory of Laser Life Science and SATCM Third Grade Laboratory of Chinese Medicine and Photonics Technology College of BiophotonicsSouth China Normal University

Graphene oxide （GO）/Ag nanoparticle （NP） hybrids are obtained by in situ reduction of Ag NPs on GO sheets. In this letter, the influence of the conformation of GO sheets on the surface-enhanced Raman scattering （SERS） effect of GO/Ag NPs is investigated by covalently grafting folic acid （FA） molecules onto graphite sheets. SERS measurements are conducted in aqueous solutions with different pH values. Data show that the SERS signals of FA are pH dependent, consistent with the morphological changes of GO sheets.

关键词： Conformations Graphene Nanoparticles Raman scattering surface scattering

Tunable perpendicular anisotropic magnetoresistance in CoO/Co/Pt heterostructures

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稀有金属：英文版 2023年第2期42卷 579-584页

作者： Qian-Qian Liu Guang Yang Jing-Yan Zhang Guo-Nan Feng Chun Feng Qian Zhan Ming-Hua Li Guang-Hua Yu Department of Materials Physics and Chemistry University of Science and Technology BeijingBeijing100083China

Transport properties of magnetron-sputtered CoO/Co/Pt heterostructures were investigated by physical property measurement *** types of magnetoresistance are observed in the heterostructures,including isotropic anisotropic magnetoresistance(AMR),AMR with geometric size effect,and interfacial effect.A reversal in sign of perpendicular AMR is found in the film CoO(3 nm)/Co(3 nm)/Pt(3 nm)compared to the film CoO(3 nm)/Co(3 nm)/CoO(3 nm),which is associated with ***,perpendicular AMR is tunable in the films CoO(3 nm)/Co(3 nm)/CoO(t)/Pt(3 nm)and CoO(3 nm)/Co(3 nm)/Pt(t)/CoO(3 nm)at will,with either positive or negative value,by varying the inserting layer *** electronic structure information of the samples was measured by X-ray photoelectron spectroscopy(XPS).The spin-related transport and XPS results manifest that magnetic proximity effect,surface scattering,together with oxygen migration contribute to the tunable function of Pt.

关键词： Perpendicular anisotropic magnetoresistance Magnetic proximity effect surface scattering X-ray photoelectron spectroscopy

The spin Hall effect in single-crystalline gold thin films

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Chinese Physics B 2016年第10期25卷 350-354页

作者：田岱陈才干王华金晓峰 State Key Laboratory of surface Physics and Department of Physics Fudan University Collaborative Innovation Center of Advanced Microstructures Fudan University

The spin Hall effect has been investigated in 10-nm-thick epitaxial Au(001) single crystal films via H-pattern devices,whose minimum characteristic dimension is about 40 nm. By improving the film quality and optimizing the in-plane geometry parameters of the devices, we explicitly extract the spin Hall effect contribution from the ballistic and bypass contribution which were previously reported to be dominating the non-local voltage. Furthermore, we calculate a lower limit of the spin Hall angle of 0.08 at room temperature. Our results indicate that the giant spin Hall effect in Au thin films is dominated not by the interior defects scattering, but by the surface scattering. Besides, our results also provide an additional experimental method to determine the magnitude of spin Hall angle unambiguously.

关键词： gold thin film spin Hall effect surface scattering

Curvature optical fiber sensor by using bend enhanced method

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Frontiers of Optoelectronics 2009年第2期2卷 204-209页

作者： Jianrong ZHANG Hairong LIU Xinkun WU College of Optoelectronic Science and Engineering Huazhong University of Science and Technology State Key Laboratory of Modern Optical Instruments Zhejiang University

Deflection curvature measurement can offer a number of advantages compared with the well-established strain measurement alternative. It is able to measure thin structure; fiber has no resistance with force, which leads to a high precision. There are many kinds of curvature gauges with different operation principles. A low-cost curvature optical fiber sensor using bend enhanced method to improve its curvature measurement sensitivity was developed in recent years. This sensor can distinguish between convex bending and concave bending and has a good linearity in measuring large curvature *** gallery ray theory and Monte Carlo simulation are new achievements by computer experiment. The operation mechanism of this curvature optical fiber sensor is presented based on light scattering theory. The attenuation is ascribed to the transmission mode changing by the curvature of the fiber, which affects the attenuation of the surface scattering. The mathematical model of relationship among light loss, bending curvature, surface roughness, and parameters of the fiber's configuration is also presented. We design different kinds of shapes of sensitive zones; each zone has different *** detecting their output optical attenuations in different curvatures and fitting the results by exponential decaying functions, the proposed model is demonstrated by experimental results. Also, we compare the experimental results with the theoretical analysis and discuss the sensitivity dependence on bending direction.

关键词： curvature measurement surface scattering operation mechanism sensitized optical fiber sensitive zone bending direction