The effect of changing Be doping concentration in GaAs layer on the integrated photosensitivity for nega- tive-electron-affinity GaAs photocathodes is investigated. Two GaAs samples with the monolayer structure and th...The effect of changing Be doping concentration in GaAs layer on the integrated photosensitivity for nega- tive-electron-affinity GaAs photocathodes is investigated. Two GaAs samples with the monolayer structure and the muhilayer structure are grown by molecular beam epitaxy. The former has a constant Be concentration of 1 × 10^19 cm^-3, while the latter includes four layers with Be doping concentrations of 1 × 10^19, 7 × 10^18, 4 × 10^18, and 1 × 10^18 cm^-3 from the bottom to the surface. Negative-electron-affinity GaAs photocathodes are fabricated by exciting the sample surfaces with alternating input of Cs and O in the high vacuum system. The spectral response results measured by the on-line spectral response measurement system show that the integrated photosensitivity of the photocathode with the muhilayer structure enhanced by at least 50% as compared to that of the monolayer structure. This attributes to the improvement in the crystal quality and the increase in the surface escape probability. Different stress situations are observed on GaAs samples with monolayer structure and muhilayer structure, respectively.展开更多
The forbidden pitch ＂dip＂ in the critical dimension （CD） through the pitch curve is a well-known optical proximity effect. The CD and CD process window near the ＂dip＂,usually found near a pitch range of 1.1 to 1...The forbidden pitch ＂dip＂ in the critical dimension （CD） through the pitch curve is a well-known optical proximity effect. The CD and CD process window near the ＂dip＂,usually found near a pitch range of 1.1 to 1.4 wavelength/ NA （numerical aperture）,is smaller when compared with other pitches. This is caused by inadequate imaging contrast for an unequal line and space grating. Although this effect is relatively well-known, its relationship with typical process condition parameters,such as the effective image blur caused by the photo-acid diffusion during the post exposure bake or the aberration in the imaging lens, has not been systematically studied. In this paper, we will examine the correlation between the image blur and the effect on the CD, including the decrease in the CD value （the depth of the ＂dip＂） and the CD process window. We find that both the decrease in the CD value and the focus latitude near the forbidden pitch correlate very well with the effective Gaussian image blur. Longer effective diffusion length correlates well with a smaller process window and a deeper CD ＂dip＂. We conclude that the dip depth is very sensitive to the change in image contrast.展开更多
Femtosecond time-resolved transient grating technique was adopted to insight into the intra-chain exciton diffusion of MEH-PPV in solution with different polarity. Broadband white-light continuum was introduced as the...Femtosecond time-resolved transient grating technique was adopted to insight into the intra-chain exciton diffusion of MEH-PPV in solution with different polarity. Broadband white-light continuum was introduced as the probe to observe the transient absorption and the femtosecond time-resolved transient grating information simultaneously. The vibrational dephasing behaviors, single exciton relaxation, and population relaxation dynamics of MEH-PPV were systematically investigated. The result shows that the relaxation processes of the sample solution will be accelerated in the solvent with larger polarity.展开更多
O437 99042461研究分子非线性光学特性的新技术—超瑞利散射技术=A newly developed hyper—Rayleigh scattering(HRS)technique for the study of the nonlinearoptical properties of molecules[刊,中]/汪昕,崔一平(东南大学分子与生...O437 99042461研究分子非线性光学特性的新技术—超瑞利散射技术=A newly developed hyper—Rayleigh scattering(HRS)technique for the study of the nonlinearoptical properties of molecules[刊,中]/汪昕,崔一平(东南大学分子与生物分子电子学实验室,光电子技术实验室.江苏,南京(210096))//中国激光.—1999,26(1).—15—20介绍了九十年代发展起来的超瑞利散射(HRS)技术的简史、理论,研究意义以及作者目前的研究工作。HRS是溶液或气体分子的二阶或高阶非相干散射,通过HRS技术不仅可以测定分子的超极化率,可以了解分子结构和分子间的相互作用。给出了HRS技术的实验装置及分析方法,并总结了其优越于传统的电场诱导二次谐波产生(EFISHG)技术的特点。图5表1参17(赵桂云)O437 99042462采用电光调制的强散射介质的扩散光子密度波取象研究=Diffusive photon density waves imaging ofobjects in highly scattering media by used electro—optic modulation[刊,中]/王桂芬,马根源,张存渊,张光寅(南开大学物理系.天津(300071))//中国学术期刊文摘(科技快报).—1999,5(4).—图1参5采用电光调制器对入射的连续光进行强度调制,使其成为声频和超声频正弦调制光,射入模拟的生物组织中进行探测。展开更多
Q63 2002021597光子扩散理论及其在生物医学中的应用=Photon dif-fusion theory and its application to biomedicine[刊,中]/吴龟灵,骆清铭,曾绍群,穆晨鹏,刘贤德(华中科技大学生物医学光子学研究所.湖北,武汉(430074))∥光电子·...Q63 2002021597光子扩散理论及其在生物医学中的应用=Photon dif-fusion theory and its application to biomedicine[刊,中]/吴龟灵,骆清铭,曾绍群,穆晨鹏,刘贤德(华中科技大学生物医学光子学研究所.湖北,武汉(430074))∥光电子·激光.—2001,12(3).—323-328介绍了目前生物医学光子学领域内的新技术-扩散光子密度波技术的理论基础。展开更多
The synthesis, characterization and swelling equilibrium of chitosan film in water-solvent mixtures were investigated. Chitosan film was prepared by reacting chitosan with 2% v/v glacial acetic acid. The film was char...The synthesis, characterization and swelling equilibrium of chitosan film in water-solvent mixtures were investigated. Chitosan film was prepared by reacting chitosan with 2% v/v glacial acetic acid. The film was characterized by Fourier transform Infra-red spectroscopy （FT-IR）, X-ray diffractometry （XRD） and scanning electron microscopy （SEM） to determine its structure and morphology. The swelling behavior of this chitosan film was further investigated in water-solvent （methanol, ethanol, butanol and acetone） mixtures gravimetrically at different temperatures and pH. The equilibrium and dynamic swelling properties were studied to investigate the pH-sensitive behavior of the gels. The hydrogel demonstrated critical swelling behavior as the pH approached 6.8. The dynamic swelling was performed and the results were analyzed using a＂ second-order model to calculate the time constant of the swelling. The values of percentage equilibrium swelling of chitosan film in water were higher than the values in organic solvents. The values range from 105.23% ± 0.28% to 131.83% ± 0.41% in water but in organic solvents it ranges from 48.68% ± 0.38% to 96.11% ± 0.02%. The results of the swelling measurement in organic solvent were compared with the prediction of the Flory-Rehner theory of swelling equilibrium. It was shown that the theory correctly predicted the swelling behavior of the hydrogel up to 60% solvent concentration. Diffusion behavior was also investigated. The calculated diffusion exponent is greater than 0.5 indicating that the diffusion of solvent into the film was non-Fickian and could be described as anomalous. Generally, the sorption process was found to be endothennic, feasible and spontaneous.展开更多
The development of InGaAs/InP single-photon avalanche photodiodes(SPADs)necessitates the utiliza-tion of a two-element diffusion technique to achieve accurate manipulation of the multiplication width and the dis-tribu...The development of InGaAs/InP single-photon avalanche photodiodes(SPADs)necessitates the utiliza-tion of a two-element diffusion technique to achieve accurate manipulation of the multiplication width and the dis-tribution of its electric field.Regarding the issue of accurately predicting the depth of diffusion in InGaAs/InP SPAD,simulation analysis and device development were carried out,focusing on the dual diffusion behavior of zinc atoms.A formula of X_(j)=k√t-t_(0)+c to quantitatively predict the diffusion depth is obtained by fitting the simulated twice-diffusion depths based on a two-dimensional(2D)model.The 2D impurity morphologies and the one-dimensional impurity profiles for the dual-diffused region are characterized by using scanning electron micros-copy and secondary ion mass spectrometry as a function of the diffusion depth,respectively.InGaAs/InP SPAD devices with different dual-diffusion conditions are also fabricated,which show breakdown behaviors well consis-tent with the simulated results under the same junction geometries.The dark count rate(DCR)of the device de-creased as the multiplication width increased,as indicated by the results.DCRs of 2×10^(6),1×10^(5),4×10^(4),and 2×10^(4) were achieved at temperatures of 300 K,273 K,263 K,and 253 K,respectively,with a bias voltage of 3 V,when the multiplication width was 1.5µm.These results demonstrate an effective prediction route for accu-rately controlling the dual-diffused zinc junction geometry in InP-based planar device processing.展开更多
For non-destructive optical characterization, laser beam induced current(LBIC) microscopy has been developed into as a quantitative tool to examine individual photodiodes within a large pixel array. Two-dimensional LB...For non-destructive optical characterization, laser beam induced current(LBIC) microscopy has been developed into as a quantitative tool to examine individual photodiodes within a large pixel array. Two-dimensional LBIC microscopy, also generally called photocurrent mapping(PC mapping), can provide spatially resolved information about local electrical properties and p-n junction formation in photovoltaic infrared(including visible light) photodetectors from which it is possible to extract material and device parameters such as junction area, junction depth, diffusion length, leakage current position and minority carrier diffusion length etc. This paper presents a comprehensive review of research background, operating principle, fundamental issues, and applications of LBIC or PC mapping.展开更多
文摘The effect of changing Be doping concentration in GaAs layer on the integrated photosensitivity for nega- tive-electron-affinity GaAs photocathodes is investigated. Two GaAs samples with the monolayer structure and the muhilayer structure are grown by molecular beam epitaxy. The former has a constant Be concentration of 1 × 10^19 cm^-3, while the latter includes four layers with Be doping concentrations of 1 × 10^19, 7 × 10^18, 4 × 10^18, and 1 × 10^18 cm^-3 from the bottom to the surface. Negative-electron-affinity GaAs photocathodes are fabricated by exciting the sample surfaces with alternating input of Cs and O in the high vacuum system. The spectral response results measured by the on-line spectral response measurement system show that the integrated photosensitivity of the photocathode with the muhilayer structure enhanced by at least 50% as compared to that of the monolayer structure. This attributes to the improvement in the crystal quality and the increase in the surface escape probability. Different stress situations are observed on GaAs samples with monolayer structure and muhilayer structure, respectively.
文摘The forbidden pitch ＂dip＂ in the critical dimension （CD） through the pitch curve is a well-known optical proximity effect. The CD and CD process window near the ＂dip＂,usually found near a pitch range of 1.1 to 1.4 wavelength/ NA （numerical aperture）,is smaller when compared with other pitches. This is caused by inadequate imaging contrast for an unequal line and space grating. Although this effect is relatively well-known, its relationship with typical process condition parameters,such as the effective image blur caused by the photo-acid diffusion during the post exposure bake or the aberration in the imaging lens, has not been systematically studied. In this paper, we will examine the correlation between the image blur and the effect on the CD, including the decrease in the CD value （the depth of the ＂dip＂） and the CD process window. We find that both the decrease in the CD value and the focus latitude near the forbidden pitch correlate very well with the effective Gaussian image blur. Longer effective diffusion length correlates well with a smaller process window and a deeper CD ＂dip＂. We conclude that the dip depth is very sensitive to the change in image contrast.
基金supported by the National Natural Science Foundation of China(No.61704120)Science & Technology Development Foundation of Tianjin Higher Education Institutions(No.20140904)
文摘Femtosecond time-resolved transient grating technique was adopted to insight into the intra-chain exciton diffusion of MEH-PPV in solution with different polarity. Broadband white-light continuum was introduced as the probe to observe the transient absorption and the femtosecond time-resolved transient grating information simultaneously. The vibrational dephasing behaviors, single exciton relaxation, and population relaxation dynamics of MEH-PPV were systematically investigated. The result shows that the relaxation processes of the sample solution will be accelerated in the solvent with larger polarity.
文摘O437 99042461研究分子非线性光学特性的新技术—超瑞利散射技术=A newly developed hyper—Rayleigh scattering(HRS)technique for the study of the nonlinearoptical properties of molecules[刊,中]/汪昕,崔一平(东南大学分子与生物分子电子学实验室,光电子技术实验室.江苏,南京(210096))//中国激光.—1999,26(1).—15—20介绍了九十年代发展起来的超瑞利散射(HRS)技术的简史、理论,研究意义以及作者目前的研究工作。HRS是溶液或气体分子的二阶或高阶非相干散射,通过HRS技术不仅可以测定分子的超极化率,可以了解分子结构和分子间的相互作用。给出了HRS技术的实验装置及分析方法,并总结了其优越于传统的电场诱导二次谐波产生(EFISHG)技术的特点。图5表1参17(赵桂云)O437 99042462采用电光调制的强散射介质的扩散光子密度波取象研究=Diffusive photon density waves imaging ofobjects in highly scattering media by used electro—optic modulation[刊,中]/王桂芬,马根源,张存渊,张光寅(南开大学物理系.天津(300071))//中国学术期刊文摘(科技快报).—1999,5(4).—图1参5采用电光调制器对入射的连续光进行强度调制,使其成为声频和超声频正弦调制光,射入模拟的生物组织中进行探测。
文摘Q63 2002021597光子扩散理论及其在生物医学中的应用=Photon dif-fusion theory and its application to biomedicine[刊,中]/吴龟灵,骆清铭,曾绍群,穆晨鹏,刘贤德(华中科技大学生物医学光子学研究所.湖北,武汉(430074))∥光电子·激光.—2001,12(3).—323-328介绍了目前生物医学光子学领域内的新技术-扩散光子密度波技术的理论基础。
文摘The synthesis, characterization and swelling equilibrium of chitosan film in water-solvent mixtures were investigated. Chitosan film was prepared by reacting chitosan with 2% v/v glacial acetic acid. The film was characterized by Fourier transform Infra-red spectroscopy （FT-IR）, X-ray diffractometry （XRD） and scanning electron microscopy （SEM） to determine its structure and morphology. The swelling behavior of this chitosan film was further investigated in water-solvent （methanol, ethanol, butanol and acetone） mixtures gravimetrically at different temperatures and pH. The equilibrium and dynamic swelling properties were studied to investigate the pH-sensitive behavior of the gels. The hydrogel demonstrated critical swelling behavior as the pH approached 6.8. The dynamic swelling was performed and the results were analyzed using a＂ second-order model to calculate the time constant of the swelling. The values of percentage equilibrium swelling of chitosan film in water were higher than the values in organic solvents. The values range from 105.23% ± 0.28% to 131.83% ± 0.41% in water but in organic solvents it ranges from 48.68% ± 0.38% to 96.11% ± 0.02%. The results of the swelling measurement in organic solvent were compared with the prediction of the Flory-Rehner theory of swelling equilibrium. It was shown that the theory correctly predicted the swelling behavior of the hydrogel up to 60% solvent concentration. Diffusion behavior was also investigated. The calculated diffusion exponent is greater than 0.5 indicating that the diffusion of solvent into the film was non-Fickian and could be described as anomalous. Generally, the sorption process was found to be endothennic, feasible and spontaneous.
基金Supported by Shanghai Natural Science Foundation(22ZR1472600).
文摘The development of InGaAs/InP single-photon avalanche photodiodes(SPADs)necessitates the utiliza-tion of a two-element diffusion technique to achieve accurate manipulation of the multiplication width and the dis-tribution of its electric field.Regarding the issue of accurately predicting the depth of diffusion in InGaAs/InP SPAD,simulation analysis and device development were carried out,focusing on the dual diffusion behavior of zinc atoms.A formula of X_(j)=k√t-t_(0)+c to quantitatively predict the diffusion depth is obtained by fitting the simulated twice-diffusion depths based on a two-dimensional(2D)model.The 2D impurity morphologies and the one-dimensional impurity profiles for the dual-diffused region are characterized by using scanning electron micros-copy and secondary ion mass spectrometry as a function of the diffusion depth,respectively.InGaAs/InP SPAD devices with different dual-diffusion conditions are also fabricated,which show breakdown behaviors well consis-tent with the simulated results under the same junction geometries.The dark count rate(DCR)of the device de-creased as the multiplication width increased,as indicated by the results.DCRs of 2×10^(6),1×10^(5),4×10^(4),and 2×10^(4) were achieved at temperatures of 300 K,273 K,263 K,and 253 K,respectively,with a bias voltage of 3 V,when the multiplication width was 1.5µm.These results demonstrate an effective prediction route for accu-rately controlling the dual-diffused zinc junction geometry in InP-based planar device processing.
基金supported by the State Key Program for Basic Research of China(Grant No.2014CB921600)the National Natural Science Foundation of China(Grant Nos.11322441 and 11274331)the Fund of Shanghai Science and Technology Foundation(Grant No.14JC1406400)
文摘For non-destructive optical characterization, laser beam induced current(LBIC) microscopy has been developed into as a quantitative tool to examine individual photodiodes within a large pixel array. Two-dimensional LBIC microscopy, also generally called photocurrent mapping(PC mapping), can provide spatially resolved information about local electrical properties and p-n junction formation in photovoltaic infrared(including visible light) photodetectors from which it is possible to extract material and device parameters such as junction area, junction depth, diffusion length, leakage current position and minority carrier diffusion length etc. This paper presents a comprehensive review of research background, operating principle, fundamental issues, and applications of LBIC or PC mapping.
