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Carrier transport mechanisms in semiconductor nanostructures and devices

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Journal of Semiconductors 2018年第6期39卷 30-42页

作者： M.A.Rafiq micro and Nano Devices Group Department of Metallurgy and Materials EngineeringPakistan Institute of Engineering and Applied Sciences

Semiconductor nanostructures have gained importance due to their potential application in future nano- electronic devices. For such applications, it is extremely important to understand the electrical properties of semi- conductor nanostructures. This review presents an overview of techniques to measure the electrical properties of individual and clusters of semiconductor nanostructures using microcopy based techniques or by fabricating metal- lic electrical contacts using lithography. Then it is shown that current-voltage （I-V） characteristics can be used to determine the conduction mechanism in these nanostructures. It has been explained that various material paramet- ers can be extracted from I-V characteristics. The frequently observed conduction mechanism in these nanostruc- tures such as thermally activated conduction, space charge limited current （SCLC）, hopping conduction, Poole Frenkel conduction, Schottky emission and Fowler Nordheim （FN） tunneling are explained in detail.

关键词： semiconductor nanostructures electrical conduction electrical contacts lithography microscopy

Perovskite-based low-cost and high-efficiency hybrid halide solar cells

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Photonics Research 2014年第5期2卷 111-120页

作者： Jiandong Fan Baohua Jia Min Gu Centre for micro-Photonics Faculty of ScienceEngineering and TechnologySwinburne University of TechnologyHawthornVictoria 3122Australia

A cost-effective and high-throughput material named perovskite has proven to be capable of converting 15.9%of the solar energy to electricity,compared to an efficiency of 3.8%that was obtained only four years *** has already outperformed most of the thin-film solar cell technologies that researchers have been studying for ***,the architecture of perovskite solar cells has been simplified from the traditional dye-sensitized solar cells to planar-heterojunction solar ***,the performance of perovskite in solar cells has attracted intensive attention and ***,many transformative steps will be put forward over the coming few *** this review,we summarize the recent exciting development in perovskite solar cells,and discuss the fundamental mechanisms of perovskite materials in solar cells and their structural *** addition,future directions and prospects are proposed toward high-efficiency perovskite solar cells for practical applications.

关键词： perovskite halide simplified

Review on the Fabrication of Surface Functional Structures for Enhancing Bioactivity of Titanium and Titanium Alloy Implants

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Chinese Journal of Mechanical engineering 2024年第4期37卷 23-49页

作者： Heng Tang Jiaxiang Xu Bin Guo Yansong Xie Yalong Sun Yanjun Lu Yong Tang Guangdong Provincial Key Laboratory of micro/Nano Optomechatronics engineering College of Mechatronics and Control EngineeringShenzhen UniversityShenzhen 518000China School of Mechanical and Power engineering Zhengzhou UniversityZhengzhou 450001China

Titanium and its alloys have been widely applied in many biomedical fields because of its excellent mechanical properties,corrosion resistance and good ***,problems such as rejection,shedding and infection will occur after titanium alloy implantation due to the low biological activity of titanium alloy *** structures with specific functions,which can enhance osseointegration and antibacterial properties,are fabricated on the surface of titanium implants to improve the biological activity between the titanium implants and human *** paper presents a comprehensive review of recent developments and applications of surface functional structure in titanium and titanium alloy *** applications of surface functional structure on different titanium and titanium alloy implants are introduced,and their manufacturing technologies are summarized and ***,the fabrication of various surface functional structures used for titanium and titanium alloy implants is reviewed and analyzed in ***,the challenges affecting the development of surface functional structures applied in titanium and titanium alloy implants are outlined,and recommendations for future research are presented.

关键词： Surface functional structure Titanium implant Manufacturing technology Bioactivity

Experimental Study on Condensation Heat Transfer Characteristics of R410A in Short Vertical Tubes

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Journal of Thermal Science 2015年第3期24卷 260-268页

作者： XU Wenyun JIA Li TAN Zetao Institute of Thermal engineering School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in micro and Small Scale

An experimental study on condensation heat transfer of R410 A in short vertical tubes(8.02 mm ID and 10.7mm ID) was presented. Experiments were performed in eight short copper tubes length varied from 300 mm to 600 mm at mass fluxes range of 58–246 kg m-2s-1 and saturation temperature of 38℃. Effects of mass flux, tube length on condensation heat transfer coefficient were investigated. The distribution of temperature, thickness of condensate film and local condensation heat transfer coefficient along the tube were also analyzed.. It is indicated that the entrance effect played an important role in condensation heat transfer of vertical tube, and the influence of entrance effect on average condensation heat transfer coefficients will weaken with the length of tube in the experimental condensation. The experimental results were compared with four well known correlations available in literatures, and the Chen correlation shows good agreement with the experimental data but with ±40% deviation. A new modified condensation heat transfer correlation with 12.7% mean deviation was developed to predict the condensation heat transfer coefficients in short vertical tube based on the experimental data.

关键词： Condensation Heat transfer characteristic R410A Short vertical tube Entrance effect

Plasmonic metalens for nanofabrication

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National Science Review 2018年第2期5卷 137-138页

作者： Xiangang Luo State Key Laboratory of Optical Technologies on Nano-Fabrication and micro-engineering Institute of Optics and Electronics Chinese Academy of Sciences

INTRODUCTION Optical lithography is the primary tool for the fabrication of micro/nanostructures in micro-electronic and opto-electronic applications,which has fueled the explosive growth of the semiconductor *** the ... 详细信息

关键词： NANOFABRICATION PLASMONICS (Electronics)

The Investigation on Flow Boiling Heat Transfer of R134a in micro-channels

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Journal of Thermal Science 2015年第5期24卷 452-462页

作者： LI Xuejiao JIA Li Institute of Thermal engineering School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in micro and Small Scale

The present study reports an experimental evaluation of heat transfer characteristic of R134a flow boiling in mi- cro-channel heat sink. The heat sink is composed of 30 parallel rectangular micro-channels with cross-sectional dimensions of 500μm width and depth, as well as total length 30ram. Experiments were conducted with heat flux up to 80.212 W/cm2, mass velocity ranging from 373.33 to 1244.44 kg/m2s, vapor quality ranging from 0.06 to 0.9. The wall temperature of heat sink heated could be controlled at around 50℃. Heat transfer coefficient could be up to 180 kW/mZK. Two dominating flow patterns were observed by analyzing boiling curves. The heat trans- fer characteristics of nucleate boiling and convective boiling were presented in the study. Revised correlations of R134a flow boiling in micro-channel heat sink were carded out with the consideration of nucleate boiling and convective boiling mechanisms.

关键词： flow boiling micro-channel R134a correlation IGBT

Fluid Resistance Characteristics Research of Nanowire Rotation under a Magnetic Field

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Journal of Thermal Science 2015年第1期24卷 73-81页

作者： Lixin Yang Nan Zhao Li Jia Institute of Thermal engineering School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing Key Laboratory of flow and heat transfer of phase changing in micro and small scale

In this study, a visualization-based experiment was performed to measure the motion of the nanowire under a magnetic field. A simulation method based on a multiple reference flame model （MRF model） was used to calcu- late fluid torque. Here, it was validated with the experimental data and theoretical results. Fluid torque of steady rotated nanowire was simulated and compared using experiment and theoretical models. The unsteady rotated condition was studied using transient simulation to compare with theory and the results showed that the accelera- tion of nanowire did not affect the flow field, indicating that the theoretical models based on the steady condition were still valid. The influence of solid walls on nanowire rotation was also studied here. The results showed that if the nanowire was placed close to the wall, the viscous force of wall would increase the velocity gradient around the nanowire, causing higher torque predictions. The fluid torque decreased quickly when the vertical distance between nanowire and wall exceeded 5 times the diameter of the wire.

关键词： Nanowire rotation simulation fluid torque wall effect

Unsupervised discovery of thin-film photovoltaic materials from unlabeled data

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npj Computational Materials 2021年第1期7卷 1144-1154页

作者： Zhilong Wang Junfei Cai Qingxun Wang SiCheng Wu Jinjin Li National Key Laboratory of Science and Technology on micro/Nano Fabrication Shanghai Jiao Tong UniversityShanghaiChina Department of micro/Nano Electronics School of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghaiChina

Quaternary chalcogenide semiconductors(I_(2)-II-IV-X_(4))are key materials for thin-film photovoltaics(PVs)to alleviate the energy *** up of PVs requires the discovery of I_(2)-II-IV-X_(4) with good photoelectric properties;however,the structure search space is significantly large to explore *** scarcity of available data impedes even many machine learning(ML)***,we employ the unsupervised learning(UL)method to discover I2-II-IV-X4 that alleviates the challenge of data *** screen all the I_(2)-II-IV-X_(4) from the periodic table as the initial data and finally select eight candidates through *** predicted by ab initio calculations,they exhibit good optical conversion efficiency,strong optical responses,and good thermal stabilities at room *** typical case demonstrates the potential of UL in material discovery,which overcomes the limitation of data scarcity,and shortens the computational screening cycle of I_(2)-II-IV-X_(4) by~12.1 years,providing a research avenue for rapid material discovery.

关键词： film overcome finally

Dimensional Analysis on Resistance Characteristics of Labyrinth Seals

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Journal of Thermal Science 2014年第6期23卷 516-522页

作者： HU Dongxu JIA Li YANG Lixin Institute of Thermal engineering School of MechanicalElectronic and Control EngineeringBeijing Jiaotong University Beijing Key Laboratory of flow and heat transfer of phase changing in micro and small scale

Experimental investigation of stepped and straight-through labyrinth seals was designed to study the sealing performance of two different typical labyrinth *** order to facilitate dimensional analysis on the flow resistance characteristics of labyrinth seals,the variable cross-section of the flow channels are considered as constant cross-section *** mechanical energy loss of flow caused by throttle turbulence intensity is considered as caused by friction along the *** friction coefficient of stepped labyrinth seals is bigger than that of straight-through labyrinth seals by more than 40% for the same Reynolds number and the ratio of equivalent diameter and the seal *** expression of friction coefficient /and /Re are obtained from experimental *** verifications indicate that the expressions are highly *** contribution to the total pressure drop of each tooth cavity gradually becomes less along the flow direction.

关键词： straight-through labyrinth seal stepped and straight-through labyrinth seal dimensional analysis resistance characteristic