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Thickness-dependent enhanced optoelectronic performance of surface charge transfer-doped ReS2 photodetectors

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Nano Research 2022年第4期15卷 3638-3646页

作者： Peiyu Zeng Wenhui Wang Jie Jiang Zheng Liu Dongshuang Han Shuojie Hu Jiaoyan He Peng Zheng Hui Zheng Liang Zheng Xiaojing Yao Weitao Su Dexuan Huo Zhangting Wu Zhenhua Ni Yang Zhang Lab for Nanoelectronics and NanoDevices Department of Electronics Science and TechnologyHangzhou Dianzi UniversityHangzhou 310018China School of Physics Southeast UniversityNanjing 211189China Jiangsu Province Special Equipment Safety Supervision and Inspection Institute Wuxi 214170China School of Sciences Hangzhou Dianzi UniversityHangzhou 310018China College of Physics and Hebei Advanced Thin Film Laboratory Hebei Normal UniversityShijiazhuang 050024China Institute of Materials Physics Hangzhou Dianzi UniversityHangzhou 310018China

Surface charge transfer doping has been widely utilized to tune the electronic and optical properties of semiconductor photodetectors based on low-dimensional materials.Although many studies have been conducted on the performance(response time,responsivity,etc.)of doped photodetectors and their mechanisms,they merely examined a specific Thickness and did not systematically explore the dependence of doping effects on the number of layers.This work performs a series of investigations on ReS_(2)photodetectors with different numbers of layers and demonstrates that the p-dopant tetrafluorotetracyanoquinodimethane(F_(4)-TCNQ)converts the deep trap states into recombination centers for few-layer ReS_(2)and induces a vertical p-n junction for thicker ReS_(2).A response time of 200 ms is observed in the decorated 2-layer ReS_(2)photodetector,more than two orders of magnitude faster than the response of the pristine photodetector,due to the disappearance of deep trap states.A current rectification ratio of 30 in the F_(4)-TCNQ-decorated sandwiched ReS_(2)device demonstrates the formation of a vertical p-n junction in a thicker ReS_(2)device.The responsivity is as high as 2,000 A/W owing to the strong carrier separation of the p-n junction.Different Thicknesses of ReS_(2)enable switching of the prominent operating mechanism between transforming deep trap states into recombination centers and forming a vertical p-n junction.The Thicknessdependent doping effect of a two-dimensional material serves as a new mechanism and provides a scheme toward improving the performance of other semiconductor devices,especially optical and electronic devices based on low-dimensional materials.

关键词： Surface charge transfer doping ReS_(2) Thickness response time responsivity tetrafluorotetracyanoquinodimethane(F_(4)-TCNQ)

Polarization Measurement Method Based on Liquid Crystal Variable Retarder(LCVR)for Atomic Thin-Film Thickness

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Nanomanufacturing and Metrology 2022年第2期5卷 159-166页

作者： Yucong Yuan Chengyuan Yao Wanfu Shen Xiaodong Hu Chunguang Hu State Key Laboratory of Precision Measuring Technology and Instruments Tianjin UniversityTianjin300072China

Atomic Thickness thin films are critical functional materials and structures in atomic and close-to-atomic scale manufacturing.However,fast,facile,and highly sensitive precision measurement of atomic film Thickness remains challenging.The reflected light has a dramatic phase change and extreme reflectivity considering the Brewster angle,indicating the high sensitivity of the optical signal to film Thickness near this angle.Hence,the precision polarization measurement method focusing on Brewster angle is vital for the ultrahigh precision characterization of thin films.A precision polarization measurement method based on a liquid crystal variable retarder(LCVR)is proposed in this paper,and a measurement system with a high angular resolution is established.A comprehensive measurement system calibration scheme is also introduced to accommodate ultrahigh precision film Thickness measurement.Repeatable measurement accuracy to the subnanometer level is achieved.Standard silicon oxide film samples of different Thicknesses were measured around Brewster angle using the self-developed system and compared with a commercial ellipsometer to verify the measurement accuracy.The consistency of the Thickness measurement results demonstrates the feasibility and robustness of the measurement method and calibration scheme.This study also demonstrates the remarkable potential of the LCVR-based polarization method for atomic film Thickness measurement in ultraprecision manufacturing.

关键词： Atomic Thickness thin film Thickness Polarization measurement Brewster angle LCVR

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Neuroscience Bulletin 2019年第4期35卷 688-696页

作者： Yin Lin Mingli Li Yi Zhou Wei Deng Xiaohong Ma Qiang Wang Wanjun Guo Yinfei Li Lijun Jiang Xun Hu Nanyin Zhang Tao Li Mental Health Centre and Psychiatric Laboratory State Key Laboratory of Biotherapy West China Hospital Sichuan University Chengdu 610041 China West China Brain Research Centre West China Hospital Sichuan University Chengdu 610041 China Department of Psychology Shenzhen Children's Hospital Shenzhen 518038 China Department of Radiology Hospital for Chengdu Office of Tibetan Autonomous Region Branch Hospital of West China Hospital Sichuan University Chengdu 610041 China Huaxi Biobank West China Hospital Sichuan University Chengdu 610041 China Department of Biomedical Engineering Huck Institutes of the Life Sciences The Pennsylvania State University University Park PA 16802 USA

Substantial evidence supports the neurodevelopmental hypothesis of schizophrenia.Meanwhile,progressive neurodegenerative processes have also been reported,leading to the hypothesis that neurodegeneration is a characteristic component in the neuropathology of schizophrenia.However,a major challenge for the neurodegenerative hypothesis is that antipsychotic drugs used by patients have profound impact on brain structures.To clarify this potential confounding factor,we measured the cortical Thickness across the whole brain using highresolution T1-weighted magnetic resonance imaging in 145 first-episode and treatment-naive patients with schizophrenia and 147 healthy controls.The results showed that,in the patient group,the frontal,temporal,parietal,and cingulate gyri displayed a significant age-related reduction of cortical Thickness.In the control group,age-related cortical Thickness reduction was mostly located in the frontal,temporal,and cingulate gyri,albeit to a lesser extent.Importantly,relative to healthy controls,patients exhibited a significantly smaller age-related cortical Thickness in the anterior cingulate,inferior temporal,and insular gyri in the right hemisphere.These results provide evidence supporting the existence of neurodegenerative processes in schizophrenia and suggest that these processes already occur in the early stage of the illness.

关键词： Schizophrenia Cortical Thickness Age-related

Macular retinal Thickness and flow density change by optical coherence tomography angiography after posterior scleral reinforcement

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Science China(Life Sciences) 2019年第7期62卷 930-936页

作者： Liya Qiao Xifang Zhang Catherine Jan Xiaoxia Li Meng Li Huaizhou Wang Beijing Tongren Eye Center Beijing Tongren HospitalCapital Medical UniversityBeijing Institute of OphthalmologyBeijing Ophthalmology and Visual Sciences Key LaboratoryBeijing 100730China Centre for Brain and Cognitive Sciences and School of Psychological and Cognitive Sciences Peking UniversityBeijing 100871China

Optical coherence tomography angiography(Angio-OCT) has introduced a new non-invasive,quantitative method to assess superficial and deep capillary networks of the retina.In this study,we investigated macular retinal Thickness and flow density change following posterior scleral reinforcement(PSR) surgery,using an RTVue XR Avanti Angio-OCT,in patients with pathological myopia.A total of 13 patients with pathological myopia were recruited and all patients completed the 6 months follow-up visit.Data from 22 eyes were used in this study.The mean age was 36.23±15.29 years,and 43%(n=6) were men.Spherical equivalent refractive error(SE) ranged from –8.0 to –24.0 D.Postoperative axial length,best-corrected visual acuity and SE did not change significantly at each follow-up,compared with pre-operative measures(P>0.05).Postoperative flow density of superficial and deep retinal layers at each sector did not change significantly at each follow-up,compared with preoperative measures(P>0.05).However,we found significant decrease in retinal Thickness of parafovea-inferior sector after PSR surgery(P<0.01),indicating potential relaxation of vitreofoveal traction after PSR surgery.

关键词： macular retinal Thickness macular flow density optical coherence tomography angiography posterior scleral reinforcement

Arctic sea ice Thickness variations from CryoSat-2 satellite altimetry data

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Science China Earth Sciences 2021年第7期64卷 1080-1089页

作者： Feng XIAO Shengkai ZHANG Jiaxing LI Tong GENG Yue XUAN Fei LI Chinese Antarctic Center of Surveying and Mapping Wuhan UniversityWuhan 430079China

Arctic sea ice plays an important role in Earth's climate and environmental system.Sea ice Thickness is one of the most important sea ice parameters.Accurately obtaining the sea ice Thickness and its changes has great significance to Arctic and global change research.Satellite altimeters can be used to derive long-term and large-scale changes in sea ice Thickness.The leads detection is vital in sea ice Thickness estimation by using satellite altimetry.Different leads detection methods are compared with remote sensing images,and results show that the detection method that uses waveform parameters can obtain improved results.The model for the conversion of freeboard to Thickness is optimized by considering the incomplete penetration of snow for radar altimeters.We derive the estimates of the Arctic sea ice Thickness for November 2010 to December 2019 by using the CryoSat-2 altimetry data.The sea ice Thickness from the IceBridge and draft data from the upward-looking sonar are used to validate our Thickness results.Validations show that the accuracy of our Thickness estimates is within 0.2 m.Variations in the Arctic sea ice Thickness are analyzed using the PIOMAS model and air and sea surface temperatures.A sharp increase in sea ice Thickness is found in 2014.

关键词： CryoSat-2 Arctic sea ice Thickness Global change

Influence of Thickness and projectile shape on penetration resistance of the compliant composite

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Defence Technology（防务技术） 2021年第1期17卷 245-256页

作者： Vishwas Mahesh Sharnappa Joladarashi Satyabodh M.Kulkarni Department of Mechanical Engineering National Institute of Technology Karnataka SurathkalMangalore 575025India Department of Industrial Engineering and Management Siddaganga Institute of TechnologyTumakuru 572103KarnatakaIndia

The present study deals with development of conceptual proof for jute rubber based flexible composite block to completely arrest the projectile impacting the target at high velocity impact of 400 m/s through numerical simulation approach using finite element(FE)method.The proposed flexible composite blocks of repeating jute/rubber/jute(JRJ)units are modelled with varying Thickness from 30 mm to 120 mm in increments of 30 mm and impacted by flat(F),ogival(O)and hemispherical(HS)shaped projectiles.All the considered projectiles are impacted with proposed flexible composite blocks of different Thicknesses and the penetration behaviour of the projectile in each case is studied.The penetration depth of the projectile in case of partially penetrated cases are considered and the effect of Thickness and projectile shape on percentage of penetration depth is statistically analyzed using Taguchi’s design of experiments(DOE).Results reveal that the though proposed flexible composite block with Thickness of 90 mm is just sufficient to arrest the complete penetration of the projectile,considering the safety issues,it is recommended to use the flexible composite with Thickness of 120 mm.The nature of damage caused by the projectile in the flexible composite is also studied.Statistical studies show that Thickness of the block plays a prominent role in determining the damage resistance of the flexible composite.

关键词： Flexible composite blocks Jute Rubber High velocity Projectile shapes Thickness Damage resistance Penetration depth

Macular choroidal Thickness in Chinese preschool children: decrease with axial length but no evident change with age

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International Journal of Ophthalmology(English edition) 2019年第9期12卷 1465-1473页

作者： Xian-Gui He Jun-Jie Deng Yao Yin Bo Zhang Shu-Yu Xiong Jian-Feng Zhu Hai-Dong Zou Xun Xu Ling Wang Department of Maternal and Child Health School of Public HealthKey Laboratory of Public Health SafetyMinistry of EducationFudan UniversityShanghai 200032China Department of Preventative Ophthalmology Shanghai Eye Disease Prevention and Treatment CenterShanghai Eye HospitalShanghai 200040China Department of Ophthalmology Shanghai General HospitalShanghai Jiao Tong University School of MedicineShanghai Key Laboratory of Ocular Fundus DiseasesShanghai Engineering Center for Visual Science and PhotomedicineShanghai 200080China

AIM: To explore the distribution pattern of macular choroidal Thickness(ChT) and its association with age as well as refractive status in Chinese preschoolers.METHODS: School-based, cross-sectional study. A total of 550 healthy preschool children aged 3 to 6 years old from 6 kindergartens were enrolled. Comprehensive ocular examinations, including measurement of visual acuity, axial length, intraocular pressure and slit-lamp examination before cycloplegia, as well as refraction measurement and sweptsource optical coherence tomography(SS-OCT) examination after cycloplegia, were performed. The macular ChT in each sector of the ETDRS grid was measured by the builtin software of SS-OCT.RESULTS: The mean central ChT of the participants was 312±59 μm. The mean axial length and spherical equivalent refraction were 22.36±0.72 mm and 1.51±0.83 D, respectively. Axial length increased with age(P0.05). The central ChT of 3-4, 5 and 6 years old children was 314±59 μm, 312±60 μm and 312±59 μm, respectively(P=0.920). No difference was observed in ChT in most of the sectors between genders. No statistical significant difference was observed among different refractive groups(all P>0.05), though the ChT of each sector seemed to be smaller in myopic children. Axial length and weight were the independent factors of central Ch T. Children with longer axial length(β=-21.184, P<0.001) and smaller weight(β=1.502, P=0.041) tended to have thinner choroid.CONCLUSION: In preschool children, the ChT remains relatively stable with age, while a negative association between ChT and axial length existed. This will be helpful to elucidate the characteristics of ChT during the early refractive development.

关键词： preschool children choroidal Thickness refractive error optical coherence tomography

Thickness-dependent mechanical properties of nacre in Cristaria plicata shell:Critical role of interfaces

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Journal of Materials Science & Technology 2020年第9期44卷 1-8页

作者： S.M.Liang H.M.Ji X.W.Li Department of Materials Physics and Chemistry School of Materials Science and EngineeringKey Laboratory for Anisotropy and Texture of MaterialsMinistry of EducationNortheastern UniversityShenyang110819China

The Thickness dependence of mechanical properties of nacre in Cristaria plicata shell was studied under three-point bending tests.The results show that the mechanical behavior of nacre exhibits a strong Thickness dependence.The bending strength firstly increases with the increase of specimen Thickness and then becomes roughly constant as the Thickness reaches a certain value of∼2.5mm.However,the mean value of work per unit volume increases constantly with increasing specimen Thickness;meanwhile,the cracking mode changes from penetration into the platelets to deflection along the interfaces.The theoretical analyses indicate that the Thickness-dependent mechanical properties of nacre are mainly caused by the variation in the number of inter-lamellar interfaces.The more the number of inter-lamellar interfaces is,the higher the strength and work of fracture of nacre under bending tests will be.However,as the number of inter-lamellar interfaces reaches a certain value(e.g.,in the present specimen with 2.5mm Thickness),the strength tends to remain constant,while the work of fracture still increases.Therefore,the present research findings are expected to provide a valuable guidance for the interfacial design of nacre-like materials with high strength and toughness.

关键词： Cristaria plicata shell Nacre Mechanical property Thickness Interface

Influence of Thickness and initial groove angle in M–K model on limit strain of 7B04 by considering through-Thickness stress

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Chinese Journal of Aeronautics 2020年第3期33卷 1074-1084页

作者： Hongrui DONG Xiaoqiang LI Haibo WANG Guiqiang GUO Dongsheng LI School of Mechanical Engineering and Automation Beihang UniversityBeijing 100083China School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China

Marciniack–Kuczinski(M–K)model is widely used to predict material's forming limit curve(FLC).The prediction of FLC traditionally neglected through-Thickness normal stress.However,it cannot be neglected in some forming processes.Much work has been done to study the effect of through-Thickness normal stress on FLC with constant through-Thickness normal stress or constant ratio of through-Thickness normal stress and maximum principal stress.In addition,based on Nakazima test process,the ratio of through-Thickness normal stress and maximum principal stress has been derived,which was a function of instantaneous Thickness and loading path.Here,initial groove angle in M–K model was not considered.In this paper,uniaxial tension tests and Nakazima tests were performed on 7B04 aluminum alloy.Based on Hill 48 yield criterion and M–K model,the prediction model of FLC was established.The increase of Thickness can enhance FLC.Meanwhile,it is necessary to consider through-Thickness normal stress and initial groove angle in prediction model.On the left side of FLC,the effect of initial groove angle on FLC is weakened by increasing sheet Thickness.On the right side of FLC,the effect of initial groove angle on FLC is strengthened by increasing sheet Thickness.On the right side of FLC,the relation between limit strain points with different Thicknesses is linear under one certain loading path.Thickness has decisive effect on through-Thickness normal stress level and the changing trendy of through-Thickness normal stress during calculation is different under different stress condition.

关键词： Forming limit Initial groove angle M–K model Non-constant through-Thickness normal stress Thickness