材料质量好坏对于获得高性能红外探测器至关重要。提出决定材料质量的关键点在于精准控制材料结构中层与层之间的晶格失配度,报道了晶格失配对材料质量和器件暗电流性能的影响。实验结论表明在液相外延技术生长的InAs/InAsSbP材料体系中...材料质量好坏对于获得高性能红外探测器至关重要。提出决定材料质量的关键点在于精准控制材料结构中层与层之间的晶格失配度,报道了晶格失配对材料质量和器件暗电流性能的影响。实验结论表明在液相外延技术生长的InAs/InAsSbP材料体系中,InAs和InAsSbP间的晶格失配不是越小越好,而是有一个最佳值。如果晶格失配偏离这个值,不管是偏大还是偏小,材料的质量都会恶化。阐述了如何调整生长参数以获得合适的晶格失配度。制备了具有适宜晶格失配度的红外探测器件,该探测器零偏压下的室温峰值探测率为6.8×10^(9) cm Hz^(1/2)W^(-1),与国际商用InAs探测器的指标相当。展开更多
In this paper, the approximation of stationary equations of the semiconductor devices with mixed boundary conditions is considered. Two schemes are proposed for the system. One is Glerkin discrete scheme, the other is...In this paper, the approximation of stationary equations of the semiconductor devices with mixed boundary conditions is considered. Two schemes are proposed for the system. One is Glerkin discrete scheme, the other is hybrid variable discrete scheme. A convergence analysis is also given.展开更多
Surface phonon-polaritons in slabs of polar ternary mixed crystals are investigated with the modified random-element-isodisplacement model and the Born-Huang approximation, based on Maxwell＇s equations with the usual...Surface phonon-polaritons in slabs of polar ternary mixed crystals are investigated with the modified random-element-isodisplacement model and the Born-Huang approximation, based on Maxwell＇s equations with the usual boundary conditions. The numerical results of the surface phonon-polariton frequencies as functions of the wave-vector and thickness for slabs of ternary mixed crystals AlxGa1-xAs, Znx Cd1-x S,and Gax In1-x N are obtained and discussed. It is shown that there are four branches of surface phonon-polaritons in slab systems. The “two-mode” and “one-mode” behaviors of surface phonon-polaritons are also shown in their dispersion curves.展开更多
In this work, we successfully synthesized bicrystalline anatase/TiO2（B） nanofibre and used it as active substrate for surface-enhanced Raman scattering （SERS） applications. The bicrystalline structured TiO2 substr...In this work, we successfully synthesized bicrystalline anatase/TiO2（B） nanofibre and used it as active substrate for surface-enhanced Raman scattering （SERS） applications. The bicrystalline structured TiO2 substrates provide additional charge transfer across the anatase-TiO2（B） interface and thus enhanced activity compared to the pure single crystalline phase. With an effort to further increase the sensitivity of SERS, nitrogen element was doped into bicrystalline anatase/TiO2（B） nanofibres （N-TiO2） and higher SERS enhancement was achieved. The nitrogen content was controlled by tuning the calcination temperature of titanate precursor at 500, 600 and 700℃, respectively. The sample calcined at 600℃ （NT600） acquires the highest percentage of nitrogen element due to its open pore structure that facilitates the diffusion of nitrogen during calcination. Raman intensity depends on the amount of nitrogen doping, thus NT600 exhibited the best SERS activity. The doped nitrogen in TiO2 facilitates the charge transfer between TiO2 and probing molecules and thus suppresses the electron-hole recombination. This work provides a new perspective on the design of efficient TiO2 SERS active substrate and is expected to be valuable for adsorbate detection on semiconductor surface.展开更多
Silicon-based high-speed electro-optical modulator is the key component of silicon photonics for future communiction and interconnection systems. In this paper, introduced are the optical mudulation mechanisms in sili...Silicon-based high-speed electro-optical modulator is the key component of silicon photonics for future communiction and interconnection systems. In this paper, introduced are the optical mudulation mechanisms in silicon, reviewed are some recent progresses in high-speed silicon modulators, and analyzed are advantages and shortages of the silicon modulators of different types.展开更多
Photocatalytic nitrogen reduction for the green synthesis of ammonia at ambient conditions has been slowed by the narrow light harvesting range,low activity and high charge recombination of photocatalysts.Plasmonic se...Photocatalytic nitrogen reduction for the green synthesis of ammonia at ambient conditions has been slowed by the narrow light harvesting range,low activity and high charge recombination of photocatalysts.Plasmonic semiconducting nanomaterials are becoming the promising candidates for nitrogen photofixation because of the broad absorption spectrum,rich defects and hot carriers.In the present study,plasmonic SrMoO_(4) is developed by regulating the concentration of oxygen vacancies that are accompanied in the reduction process from Mo^(6+) to Mo^(5+).The stable and tunable localized surface plasmon resonance(LSPR)absorption in visible and near infrared light range makes the wide bandgap SrMoO_(4) utilize the solar energy more efficiently.Energetic electrons from both the intrinsic band excitation and the LSPR excitation enable the reduction of dinitrogen molecules thermodynamically in ultrapure water to ammonia.This work provides a unique clue to design efficient photocatalysts for nitrogen fixation.展开更多
The optical parameters for three samples of intrinsic, doped Si and doped Mg (Al x Ga 1- x ) y In 1- y P prepared by the MOCVD on GaAs substrate were measured by using ellipsometry and were calc...The optical parameters for three samples of intrinsic, doped Si and doped Mg (Al x Ga 1- x ) y In 1- y P prepared by the MOCVD on GaAs substrate were measured by using ellipsometry and were calculated by the two-layer absorption film model. The results obtained were discussed. The grown rates and thickness of oxidic layer on the intrinsic (Al x Ga 1- x ) y In 1- y P surface exposed in the atmosphere were studied. A linear dependence of oxidic layer thickness on the time was obtained.展开更多
InG sP/G s SCH SQW lasers have been prepared by LP-MOCVD. The dependence of t hreshold current density on cavity length was explained. Laser diodes are char acterized by the output power of 1 W to 2 W, threshold curre...InG sP/G s SCH SQW lasers have been prepared by LP-MOCVD. The dependence of t hreshold current density on cavity length was explained. Laser diodes are char acterized by the output power of 1 W to 2 W, threshold current density ( J th ) of 330 A/cm 2 to 450 A/cm 2 and external differe ntial quantum efficiency ( η d) of 35% to 75%, and these characteristics ar e in good agreement with the designed requirement.展开更多
A new hybrid WDM/TDM passive optical network （PON） implemented by using all-optical wavelength converters （AOWCs） is proposed. The AOWCs are based on the cross-gain modulation （XGM） effect of the semiconductor o...A new hybrid WDM/TDM passive optical network （PON） implemented by using all-optical wavelength converters （AOWCs） is proposed. The AOWCs are based on the cross-gain modulation （XGM） effect of the semiconductor optical amplifier （SOA）. Moreover, the feasibility of this sys- tem is experimentally demonstrated by evaluating the impacts of the optical wavelength conversion, time domain waveforms, eye diagrams and bit-error-rate （BER） in AOWC. The results show that the proposal will be a promising solution for the next generation access networks.展开更多
micro-electro-mechanical system （MEMS） device has the advantages of both electronic system and mechanical system. With the development of MEMS devices for satellite, it is possible to establish much lighter and smal...micro-electro-mechanical system （MEMS） device has the advantages of both electronic system and mechanical system. With the development of MEMS devices for satellite, it is possible to establish much lighter and smaller nanosatellites with higher performance and longer lifecyele. The power consumption of MEMS devices is usually much lower than that of traditional devices, which will greatly reduce the consumption of power. For its small size and simple architecture, MEMS devices can be easily integrated together and achieve redundancy. Launched on April 18, 2004, NS - 1 is a nanosatellite for science exploration and MEMS devices test. A mass of science data and images were acquired during its running. NS - 1 weights less than 25 kg. It consists of several MEMS devices, including one miniature inertial measurement unit（MIMU） , three micro complementary metal oxide semiconductor （CMOS）cameras, one sun sensor, three momentum wheels, and one micro magnetic sensor. By applying micro components based on MEMS technology, NS - 1 has made success in the experiments of integrative design, manufacture, and MEMS devices integration. In this paper, some MEMS devices for nanosatellite and picosatellite are introduced, which have been tested on NS -1 nanosatellite or on the ground.展开更多
We consider the drift-diffusion （DD） model of one dimensional semiconductor devices, which is a system involving not only first derivative convection terms but also second derivative diffusion terms and a coupled Po...We consider the drift-diffusion （DD） model of one dimensional semiconductor devices, which is a system involving not only first derivative convection terms but also second derivative diffusion terms and a coupled Poisson potential equation. Optimal error estimates are obtained for both the semi-discrete and fully discrete local discontinuous Galerkin （LDG） schemes with smooth solutions. In the fully discrete scheme, we couple the implicit-explicit （IMEX） time discretization with the LDG spatial diseretization, in order to allow larger time steps and to save computational cost. The main technical difficulty in the analysis is to treat the inter-element jump terms which arise from the discontinuous nature of the numerical method and the nonlinearity and coupling of the models. A simulation is also performed to validate the analysis.展开更多
基金Supported by the National Natural Science Foundation of China (11933006)the Frontier Science Research Project (Key Programs) of the Chinese Academy of Sciences (QYZDJ-SSW-SLH018)the National Natural Science Foundation of China (U2141240)。
文摘材料质量好坏对于获得高性能红外探测器至关重要。提出决定材料质量的关键点在于精准控制材料结构中层与层之间的晶格失配度,报道了晶格失配对材料质量和器件暗电流性能的影响。实验结论表明在液相外延技术生长的InAs/InAsSbP材料体系中,InAs和InAsSbP间的晶格失配不是越小越好,而是有一个最佳值。如果晶格失配偏离这个值,不管是偏大还是偏小,材料的质量都会恶化。阐述了如何调整生长参数以获得合适的晶格失配度。制备了具有适宜晶格失配度的红外探测器件,该探测器零偏压下的室温峰值探测率为6.8×10^(9) cm Hz^(1/2)W^(-1),与国际商用InAs探测器的指标相当。
文摘In this paper, the approximation of stationary equations of the semiconductor devices with mixed boundary conditions is considered. Two schemes are proposed for the system. One is Glerkin discrete scheme, the other is hybrid variable discrete scheme. A convergence analysis is also given.
文摘Surface phonon-polaritons in slabs of polar ternary mixed crystals are investigated with the modified random-element-isodisplacement model and the Born-Huang approximation, based on Maxwell＇s equations with the usual boundary conditions. The numerical results of the surface phonon-polariton frequencies as functions of the wave-vector and thickness for slabs of ternary mixed crystals AlxGa1-xAs, Znx Cd1-x S,and Gax In1-x N are obtained and discussed. It is shown that there are four branches of surface phonon-polaritons in slab systems. The “two-mode” and “one-mode” behaviors of surface phonon-polaritons are also shown in their dispersion curves.
基金Supported by Chinese MOST 973 project(2013CB733501)the National Natural Science Foundation of China1(21136004,21476106,21606131)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Fundamental Research Funds for the Central Universities(30916011351)at Nanjing University of Science&Technology
文摘In this work, we successfully synthesized bicrystalline anatase/TiO2（B） nanofibre and used it as active substrate for surface-enhanced Raman scattering （SERS） applications. The bicrystalline structured TiO2 substrates provide additional charge transfer across the anatase-TiO2（B） interface and thus enhanced activity compared to the pure single crystalline phase. With an effort to further increase the sensitivity of SERS, nitrogen element was doped into bicrystalline anatase/TiO2（B） nanofibres （N-TiO2） and higher SERS enhancement was achieved. The nitrogen content was controlled by tuning the calcination temperature of titanate precursor at 500, 600 and 700℃, respectively. The sample calcined at 600℃ （NT600） acquires the highest percentage of nitrogen element due to its open pore structure that facilitates the diffusion of nitrogen during calcination. Raman intensity depends on the amount of nitrogen doping, thus NT600 exhibited the best SERS activity. The doped nitrogen in TiO2 facilitates the charge transfer between TiO2 and probing molecules and thus suppresses the electron-hole recombination. This work provides a new perspective on the design of efficient TiO2 SERS active substrate and is expected to be valuable for adsorbate detection on semiconductor surface.
基金National Basic Research Program of China("973"Project , 2007CB613405 and 2006CB302803)"863"National High Technology Programme of China(2006AA03Z424)
文摘Silicon-based high-speed electro-optical modulator is the key component of silicon photonics for future communiction and interconnection systems. In this paper, introduced are the optical mudulation mechanisms in silicon, reviewed are some recent progresses in high-speed silicon modulators, and analyzed are advantages and shortages of the silicon modulators of different types.
文摘Photocatalytic nitrogen reduction for the green synthesis of ammonia at ambient conditions has been slowed by the narrow light harvesting range,low activity and high charge recombination of photocatalysts.Plasmonic semiconducting nanomaterials are becoming the promising candidates for nitrogen photofixation because of the broad absorption spectrum,rich defects and hot carriers.In the present study,plasmonic SrMoO_(4) is developed by regulating the concentration of oxygen vacancies that are accompanied in the reduction process from Mo^(6+) to Mo^(5+).The stable and tunable localized surface plasmon resonance(LSPR)absorption in visible and near infrared light range makes the wide bandgap SrMoO_(4) utilize the solar energy more efficiently.Energetic electrons from both the intrinsic band excitation and the LSPR excitation enable the reduction of dinitrogen molecules thermodynamically in ultrapure water to ammonia.This work provides a unique clue to design efficient photocatalysts for nitrogen fixation.
文摘The optical parameters for three samples of intrinsic, doped Si and doped Mg (Al x Ga 1- x ) y In 1- y P prepared by the MOCVD on GaAs substrate were measured by using ellipsometry and were calculated by the two-layer absorption film model. The results obtained were discussed. The grown rates and thickness of oxidic layer on the intrinsic (Al x Ga 1- x ) y In 1- y P surface exposed in the atmosphere were studied. A linear dependence of oxidic layer thickness on the time was obtained.
文摘InG sP/G s SCH SQW lasers have been prepared by LP-MOCVD. The dependence of t hreshold current density on cavity length was explained. Laser diodes are char acterized by the output power of 1 W to 2 W, threshold current density ( J th ) of 330 A/cm 2 to 450 A/cm 2 and external differe ntial quantum efficiency ( η d) of 35% to 75%, and these characteristics ar e in good agreement with the designed requirement.
文摘A new hybrid WDM/TDM passive optical network （PON） implemented by using all-optical wavelength converters （AOWCs） is proposed. The AOWCs are based on the cross-gain modulation （XGM） effect of the semiconductor optical amplifier （SOA）. Moreover, the feasibility of this sys- tem is experimentally demonstrated by evaluating the impacts of the optical wavelength conversion, time domain waveforms, eye diagrams and bit-error-rate （BER） in AOWC. The results show that the proposal will be a promising solution for the next generation access networks.
文摘micro-electro-mechanical system （MEMS） device has the advantages of both electronic system and mechanical system. With the development of MEMS devices for satellite, it is possible to establish much lighter and smaller nanosatellites with higher performance and longer lifecyele. The power consumption of MEMS devices is usually much lower than that of traditional devices, which will greatly reduce the consumption of power. For its small size and simple architecture, MEMS devices can be easily integrated together and achieve redundancy. Launched on April 18, 2004, NS - 1 is a nanosatellite for science exploration and MEMS devices test. A mass of science data and images were acquired during its running. NS - 1 weights less than 25 kg. It consists of several MEMS devices, including one miniature inertial measurement unit（MIMU） , three micro complementary metal oxide semiconductor （CMOS）cameras, one sun sensor, three momentum wheels, and one micro magnetic sensor. By applying micro components based on MEMS technology, NS - 1 has made success in the experiments of integrative design, manufacture, and MEMS devices integration. In this paper, some MEMS devices for nanosatellite and picosatellite are introduced, which have been tested on NS -1 nanosatellite or on the ground.
基金supported by National Natural Science Foundation of China(Grant No.11471194)Department of Energy of USA(Grant No.DE-FG02-08ER25863)National Science Foundation of USA(Grant No.DMS-1418750)
文摘We consider the drift-diffusion （DD） model of one dimensional semiconductor devices, which is a system involving not only first derivative convection terms but also second derivative diffusion terms and a coupled Poisson potential equation. Optimal error estimates are obtained for both the semi-discrete and fully discrete local discontinuous Galerkin （LDG） schemes with smooth solutions. In the fully discrete scheme, we couple the implicit-explicit （IMEX） time discretization with the LDG spatial diseretization, in order to allow larger time steps and to save computational cost. The main technical difficulty in the analysis is to treat the inter-element jump terms which arise from the discontinuous nature of the numerical method and the nonlinearity and coupling of the models. A simulation is also performed to validate the analysis.
