Imagine a beanie that“sees”traffic lights for the visually impaired,or a shirt that doubles as a high-speed data receiver.These aren’t sci-fi fantasies-they’re the first threads of a revolution sparked by ultra-th...Imagine a beanie that“sees”traffic lights for the visually impaired,or a shirt that doubles as a high-speed data receiver.These aren’t sci-fi fantasies-they’re the first threads of a revolution sparked by ultra-thin,flexible semiconductor fibers.In a Nature study published February 2024,researchers from the Chinese Academy of Sciences and Nanyang Technological University unveiled a breakthrough in producing high-performance optoelectronic fibers,overcoming decades-old engineering hurdles.展开更多
Piezoelectric semiconductors(PSs)possess both semiconducting properties and piezoelectric coupling effects,making them optimal building blocks for semiconductor devices.PS fiber-like structures have wide applications ...Piezoelectric semiconductors(PSs)possess both semiconducting properties and piezoelectric coupling effects,making them optimal building blocks for semiconductor devices.PS fiber-like structures have wide applications in multi-functional semiconductor devices.In this paper,a one-dimensional(1D)theoretical model is established to describe the piezotronic responses of a PS fiber under gradient temperature changes.The theoretical model aims to explain the mechanism behind the resistance change caused by such gradient temperature changes.Numerical results demonstrate that a gradient temperature change significantly affects the physical fields within the PS fiber,and can induce changes in its surface resistance.It provides important theoretical guidance on the development of piezotronic devices that are sensitive to temperature effects.展开更多
Based on the nonlinear constitutive equation,a piezoelectric semiconductor(PSC)fiber under axial loads and Ohmic contact boundary conditions is investigated.The analytical solutions of electromechanical fields are der...Based on the nonlinear constitutive equation,a piezoelectric semiconductor(PSC)fiber under axial loads and Ohmic contact boundary conditions is investigated.The analytical solutions of electromechanical fields are derived by the homotopy analysis method(HAM),indicating that the HAM is efficient for the nonlinear analysis of PSC fibers,along with a rapid rate of convergence.Furthermore,the nonlinear characteristics of electromechanical fields are discussed through numerical results.It is shown that the asymmetrical distribution of electromechanical fields is obvious under a symmetrical load,and the piezoelectric effect is weakened by an applied electric field.With the increase in the initial carrier concentration,the electric potential decreases,and owing to the screen-ing effect of electrons,the distribution of electromechanical fields tends to be symmetrical.展开更多
Based on the mechanical motion equation,Gauss’s law,and the current continuity condition,we study a few typical transient effects in a piezoelectric semiconductor(PS)fiber to realize the startup and turning-off funct...Based on the mechanical motion equation,Gauss’s law,and the current continuity condition,we study a few typical transient effects in a piezoelectric semiconductor(PS)fiber to realize the startup and turning-off functions of common piezotronic devices.In this study,the transient extensional vibration induced by a suddenly applied axial time-dependent force is examined in a cantilevered n-type ZnO nanofiber.Neither the magnitude of the loadings nor the doping concentration significantly affects the propagation caused by disturbance of the axial displacement.However,both of the factors play an important role in the propagation caused by disturbance of the electron concentrations.This indicates that the electromechanical coupling effect can be expected to directly determine the electronic performance of the devices.In addition,the assumption of previous simplified models which neglect the charge carriers in Gauss’s law is discussed,showing that this assumption has a little influence on the startup state when the doping concentration is smaller than 1021 m-3.This suggests that the screening effect of the carriers on the polarized electric field is much reduced in this situation,and that the state is gradually transforming into a pure piezoelectric state.Nevertheless,the carriers can provide a damping effect,which means that the previous simplified models do not sufficiently describe the turning-off state.The numerical results show that the present study has referential value with respect to the design of newly multifunctional PS devices.展开更多
In this paper,we propose a specific two-layer model consisting of a functionally graded(FG)layer and a piezoelectric semiconductor(PS)layer.Based on the macroscopic theory of PS materials,the effects brought about by ...In this paper,we propose a specific two-layer model consisting of a functionally graded(FG)layer and a piezoelectric semiconductor(PS)layer.Based on the macroscopic theory of PS materials,the effects brought about by the attached FG layer on the piezotronic behaviors of homogeneous n-type PS fibers and PN junctions are investigated.The semi-analytical solutions of the electromechanical fields are obtained by expanding the displacement and carrier concentration variation into power series.Results show that the antisymmetry of the potential and electron concentration distributions in homogeneous n-type PS fibers is destroyed due to the material inhomogeneity of the attached FG layer.In addition,by creating jump discontinuities in the material properties of the FG layer,potential barriers/wells can be produced in the middle of the fiber.Similarly,the potential barrier configuration near the interface of a homogeneous PS PN junction can also be manipulated in this way,which offers a new choice for the design of PN junction based devices.展开更多
We have developed a novel optical fiber ring laser using a semiconductor optical amplifier (SOA) as the gain medium, and taking advantage of polarization anisotropy of its gain. The frequency difference of the bi-dire...We have developed a novel optical fiber ring laser using a semiconductor optical amplifier (SOA) as the gain medium, and taking advantage of polarization anisotropy of its gain. The frequency difference of the bi-directional laser is controlled by birefringence which is introduced in the ring laser cavity. The beat frequency generated by combining two counter-propagating oscillations is proportional to the birefringence, the fiber ring laser of the present study is, therefore, applicable to the fiber sensor. The sensing signal is obtained in a frequency domain with the material which causes the retardation change by a physical phenomenon to be measured. For the application to stress sensing, the present laser was investigated with a photoelastic material.展开更多
In this study,the free vibration of a piezoelectric semiconductor(PS)composite structure composed of a PS layer,a fractional viscoelastic layer,and an elastic substrate with simply-supported boundary conditions is inv...In this study,the free vibration of a piezoelectric semiconductor(PS)composite structure composed of a PS layer,a fractional viscoelastic layer,and an elastic substrate with simply-supported boundary conditions is investigated.The fractional derivative Zener model is used to establish the constitutive relation of the viscoelastic layer.The first-order shear deformation theory and Hamilton's principle are used to derive the motion equations of the present problem.The frequency parameter is numerically resolved with the Newton-Raphson method through the eigenvalue equation.The effects of either geometric parameters,carrier density,and electric voltage applied on the surface of the composite structure or the fractional order of the Zener model on both the natural frequency and loss factor are discussed,and some interesting conclusions are drawn.This work will be helpful for designing and manufacturing PS materials and structures.展开更多
This paper theoretically investigates the influence of a cylindrical PN junction on the propagation characteristics of shear cylindrical waves(SCWs)in an infinitely long piezoelectric semiconductor(PS)concentric cylin...This paper theoretically investigates the influence of a cylindrical PN junction on the propagation characteristics of shear cylindrical waves(SCWs)in an infinitely long piezoelectric semiconductor(PS)concentric cylinder structure.This PS concentric cylinder structure is composed of three regions:an inner PS cylinder,an outer PS cylindrical shell,and a cylindrical PN junction at the interface between the two aforementioned regions.First,the basic equations of the PS concentric cylinder structure are derived,taking into account the coupling of the mechanical displacement,electric potential,and charge carrier perturbation in the cylindrical coordinate system.Next,a mathematical model for the SCWs in this PS concentric cylinder structure is established,utilizing the spectral method and considering the physical characteristics of the cylindrical PN junction.Finally,the dispersion and attenuation curves of the SCWs are numerically calculated to discuss the influence of the interface effect resulting from the cylindrical PN junction.It is found that the existence of a cylindrical PN junction can either reduce or enhance the mechanical-to-electrical energy conversion,which is closely related to the doping mode,doping concentration,and curvature radius of the cylindrical interface.A reasonable design of the aforementioned parameters can optimize the wave motion in acoustic equipment formed by PS media with different frequencies or wavelengths.The construction and resolution of the mathematical model as well as the analysis of physical mechanisms can offer theoretical guidance for improving the efficiency of energy conversion from mechanical energy to electrical energy and optimizing the acoustic performance of energy harvesting devices.展开更多
Sandwich piezoelectric semiconductor(PS)structures have significant applications in multi-functional semiconductor devices.The analysis of multi-field coupling behaviors of PS structures is of fundamental importance i...Sandwich piezoelectric semiconductor(PS)structures have significant applications in multi-functional semiconductor devices.The analysis of multi-field coupling behaviors of PS structures is of fundamental importance in developing novel PS devices.In this paper,we develop a general temperature-deformation-polarization-carrier(TDPC)coupling model for sandwich-type PS beams involving pyroelectricity under thermal loadings,based on three-dimensional(3D)basic equations of the thermo-piezoelectric semiconductor(TPS).We derive analytical solutions for extensional,bending,and buckling deformations of simply-supported sandwich n-type PS beams subjected to open-circuit and electrically isolated boundary conditions.The accuracy of the proposed model in this paper is verified through finite element simulations implemented in the COMSOL software.Numerical results show that the initial electron concentration and the thickness ratio of the PS layer to the beam's total thickness have a significant effect on thermally induced extensional and bending responses,as well as critical buckling mechanical and thermal loadings.This study provides a theoretical framework and guidance for designing semiconductor devices based on sandwich PS beam structures.展开更多
Based on the nonlinear drift-diffusion(NLDD)model,the coupled behavior between the mechanical and electrical fields in piezoelectric semiconductor(PS)PN junctions under two typical loading conditions is investigated.T...Based on the nonlinear drift-diffusion(NLDD)model,the coupled behavior between the mechanical and electrical fields in piezoelectric semiconductor(PS)PN junctions under two typical loading conditions is investigated.The governing equations for the general shell structure of the PS PN junction are derived within the framework of virtual work principles and charge continuity conditions.The distributions of the electromechanical coupling field are obtained by the Fourier series expansion and the differential quadrature method(DQM),and the nonlinearity is addressed with the iterative method.Several numerical examples are presented to investigate the effects of mechanical loading on the charge carrier transport characteristics.It is found that the barrier height of the heterojunction can be effectively modulated by mechanical loading.Furthermore,a nonlinearity index is introduced to quantify the influence of nonlinearity in the model.It is noted that,when the concentration difference between the two sides is considerable,the nonlinear results differ significantly from the linear results,thereby necessitating the adoption of the NLDD model.展开更多
A semiconductor optical amplifier gate based on tensile strained quasi bulk InGaAs is developed.At injection current of 80mA,a 3dB optical bandwidth of more than 85nm is achieved due to dominant band filling effect...A semiconductor optical amplifier gate based on tensile strained quasi bulk InGaAs is developed.At injection current of 80mA,a 3dB optical bandwidth of more than 85nm is achieved due to dominant band filling effect.Moreover,the most important is that very low polarization dependence of gain (<0 7dB),fiber to fiber lossless operation current (70～90mA) and a high extinction ratio (>50dB) are simultaneously obtained over this wide 3dB optical bandwidth (1520～1609nm) which nearly covers the spectral region of the whole C band (1525～1565nm) and the whole L band (1570～1610nm).The gating time is also improved by decreasing carrier lifetime.The wide band polarization insensitive SOA gate is promising for use in future dense wavelength division multiplexing (DWDM) communication systems.展开更多
Recent success in strain engineering has triggered tremendous interest in its study and potential applications in nanodevice design. In this paper, we establish a coupled piezoelectric/semiconducting model for a wurtz...Recent success in strain engineering has triggered tremendous interest in its study and potential applications in nanodevice design. In this paper, we establish a coupled piezoelectric/semiconducting model for a wurtzite structure ZnO nanofiber under the local mechanical loading. The energy band structure tuned by the local mechanical loading and local length is calculated via an eight-band k·p method, which includes the coupling of valance and conduction bands. Poisson's effect on the distribution of electric potential inversely depends on the local mechanical loading. Numerical results reveal that both the applied local mechanical loading and the local length exhibit obvious tuning effects on the electric potential and energy band. The band gap at band edges varies linearly with the applied loading. Changing the local length shifts the energy band which is far away from the band edges. This study will be useful in the electronic and optical enhancement of semiconductor devices.展开更多
Sandwiched functionally-graded piezoelectric semiconductor(FGPS)plates possess high strength and excellent piezoelectric and semiconductor properties,and have significant potential applications in micro-electro-mechan...Sandwiched functionally-graded piezoelectric semiconductor(FGPS)plates possess high strength and excellent piezoelectric and semiconductor properties,and have significant potential applications in micro-electro-mechanical systems.The multi-field coupling and free vibration of a sandwiched FGPS plate are studied,and the governing equation and natural frequency are derived with the consideration of electron movement.The material properties in the functionally-graded layers are assumed to vary smoothly,and the first-order shear deformation theory is introduced to derive the multi-field coupling in the plate.The total strain energy of the plate is obtained,and the governing equations are presented by using Hamilton’s principle.By introducing the boundary conditions,the coupling physical fields are solved.In numerical examples,the natural frequencies of sandwiched FGPS plates under different geometrical and physical parameters are discussed.It is found that the initial electron density can be used to modulate the natural frequencies and vibrational displacement of sandwiched FGPS plates in the case of nano-size.The effects of the material properties of FGPS layers on the natural frequencies are also examined in detail.展开更多
Narrow bandgap semiconductor MgIn_(2)S_(4) has been readily grown onto In_(2)O_(3) nanofibers by an in situ growing method.The so-formed MgIn_(2)S_(4)-In_(2)O_(3) hybrid nanofibers are characterized by strong visible ...Narrow bandgap semiconductor MgIn_(2)S_(4) has been readily grown onto In_(2)O_(3) nanofibers by an in situ growing method.The so-formed MgIn_(2)S_(4)-In_(2)O_(3) hybrid nanofibers are characterized by strong visible light absorption and intimate MgIn_(2)S_(4)/In_(2)O_(3) heterointerfaces.Under visible light illumination(λ≥400 nm),the hybrid nanofibers demonstrate an exceptionally high photocatalytic activity for Escherichia coli(E.coli)disinfection,outcompeting pristine MgIn_(2)S_(4),naked In_(2)O_(3) nanofibers,and many other photocatalytic systems reported.Specifically,the hybrid nanofibers achieve a 7 log reduction in viable cells for merely 20 min illumination while pristine MgIn_(2)S_(4) and naked In_(2)O_(3) nanofibers alone are almost inactive.Further analysis indicates that the hybrid nanofibers essentially form a type-II semiconductor heterojunctions which enable spatial separation of photocarriers.Owing to the intimate heterointerfaces,photocarriers can be promptly separated and accumulated respectively in In_(2)O_(3) and MgIn_(2)S_(4) thereby allowing continuous generation of copious reactive species for disinfection.This work signifies the usefulness of heterointerfaces in promoting photocarrier separation and provides a useful strategy to upgrade photocatalytic performance from otherwise almost inactive semiconductors.展开更多
Based on the thermo-electro-elastic coupling theory,the mathematical model for a surface heated piezoelectric semiconductor(PS)plate is developed in the time domain.Applying the direct and inverse Laplace transformati...Based on the thermo-electro-elastic coupling theory,the mathematical model for a surface heated piezoelectric semiconductor(PS)plate is developed in the time domain.Applying the direct and inverse Laplace transformations to the established model,the mechanical and electrical responses are investigated.The comparison between the analytical solution and the finite element method(FEM)is conducted,which illustrates the validity of the derivation.The calculated results show that the maximum values of the mechanical and electrical fields appear at the heating surface.Importantly,the perturbation carriers tend to concentrate in the zone near the heating surface under the given boundary conditions.It can also be observed that the heating induced elastic wave leads to jumps for the electric potential and perturbation carrier density at the wavefront.When the thermal relaxation time is introduced,all the field quantities become smaller because of the thermal lagging effect.Meanwhile,it can be found that the thermal relaxation time can describe the smooth variation at the jump position.Besides,for a plate with P-N junction,the effect of the interface position on the electrical response is studied.The effects of the initial carrier density on the electrical properties are discussed in detail.The conclusions in this article can be the guidance for the design of PS devices serving in thermal environment.展开更多
文摘Imagine a beanie that“sees”traffic lights for the visually impaired,or a shirt that doubles as a high-speed data receiver.These aren’t sci-fi fantasies-they’re the first threads of a revolution sparked by ultra-thin,flexible semiconductor fibers.In a Nature study published February 2024,researchers from the Chinese Academy of Sciences and Nanyang Technological University unveiled a breakthrough in producing high-performance optoelectronic fibers,overcoming decades-old engineering hurdles.
基金Project supported by the National Natural Science Foundation of China (Nos.12172326 and 11972319)the National Key Research and Development Program of China (No.2020YFA0711700)the Natural Science Foundation of Zhejiang Province of China (No.LR21A020002)。
文摘Piezoelectric semiconductors(PSs)possess both semiconducting properties and piezoelectric coupling effects,making them optimal building blocks for semiconductor devices.PS fiber-like structures have wide applications in multi-functional semiconductor devices.In this paper,a one-dimensional(1D)theoretical model is established to describe the piezotronic responses of a PS fiber under gradient temperature changes.The theoretical model aims to explain the mechanism behind the resistance change caused by such gradient temperature changes.Numerical results demonstrate that a gradient temperature change significantly affects the physical fields within the PS fiber,and can induce changes in its surface resistance.It provides important theoretical guidance on the development of piezotronic devices that are sensitive to temperature effects.
基金supported by the National Natural Science Foundation of China(Nos.11702251,12002316)。
文摘Based on the nonlinear constitutive equation,a piezoelectric semiconductor(PSC)fiber under axial loads and Ohmic contact boundary conditions is investigated.The analytical solutions of electromechanical fields are derived by the homotopy analysis method(HAM),indicating that the HAM is efficient for the nonlinear analysis of PSC fibers,along with a rapid rate of convergence.Furthermore,the nonlinear characteristics of electromechanical fields are discussed through numerical results.It is shown that the asymmetrical distribution of electromechanical fields is obvious under a symmetrical load,and the piezoelectric effect is weakened by an applied electric field.With the increase in the initial carrier concentration,the electric potential decreases,and owing to the screen-ing effect of electrons,the distribution of electromechanical fields tends to be symmetrical.
基金the National Natural Science Foundation of China(No.11972164)the Key Laboratory Project of Hubei Province of China(No.2016CFA073)。
文摘Based on the mechanical motion equation,Gauss’s law,and the current continuity condition,we study a few typical transient effects in a piezoelectric semiconductor(PS)fiber to realize the startup and turning-off functions of common piezotronic devices.In this study,the transient extensional vibration induced by a suddenly applied axial time-dependent force is examined in a cantilevered n-type ZnO nanofiber.Neither the magnitude of the loadings nor the doping concentration significantly affects the propagation caused by disturbance of the axial displacement.However,both of the factors play an important role in the propagation caused by disturbance of the electron concentrations.This indicates that the electromechanical coupling effect can be expected to directly determine the electronic performance of the devices.In addition,the assumption of previous simplified models which neglect the charge carriers in Gauss’s law is discussed,showing that this assumption has a little influence on the startup state when the doping concentration is smaller than 1021 m-3.This suggests that the screening effect of the carriers on the polarized electric field is much reduced in this situation,and that the state is gradually transforming into a pure piezoelectric state.Nevertheless,the carriers can provide a damping effect,which means that the previous simplified models do not sufficiently describe the turning-off state.The numerical results show that the present study has referential value with respect to the design of newly multifunctional PS devices.
基金supported by the National Natural Science Foundation of China(Nos.12061131013,11972276,1211101401,12172171,and 12102183)the State Key Laboratory of Mechanics and Control of Mechanical Structures of Nanjing University of Aeronautics and Astronautics(No.MCMS-E-0520K02)+5 种基金the Fundamental Research Funds for the Central Universities of China(Nos.NE2020002 and NS2019007)the National Natural Science Foundation of China for Creative Research Groups(No.51921003)the Postgraduate Research&Practice Innovation Program of Jiangsu Province of China(No.KYCX210179)the National Natural Science Foundation of Jiangsu Province of China(No.BK20211176)the Local Science and Technology Development Fund Projects Guided by the Central Government of China(No.2021Szvup061)the Jiangsu High-Level Innovative and Entrepreneurial Talents Introduction Plan(Shuangchuang Doctor Program,No.JSSCBS20210166)。
文摘In this paper,we propose a specific two-layer model consisting of a functionally graded(FG)layer and a piezoelectric semiconductor(PS)layer.Based on the macroscopic theory of PS materials,the effects brought about by the attached FG layer on the piezotronic behaviors of homogeneous n-type PS fibers and PN junctions are investigated.The semi-analytical solutions of the electromechanical fields are obtained by expanding the displacement and carrier concentration variation into power series.Results show that the antisymmetry of the potential and electron concentration distributions in homogeneous n-type PS fibers is destroyed due to the material inhomogeneity of the attached FG layer.In addition,by creating jump discontinuities in the material properties of the FG layer,potential barriers/wells can be produced in the middle of the fiber.Similarly,the potential barrier configuration near the interface of a homogeneous PS PN junction can also be manipulated in this way,which offers a new choice for the design of PN junction based devices.
文摘We have developed a novel optical fiber ring laser using a semiconductor optical amplifier (SOA) as the gain medium, and taking advantage of polarization anisotropy of its gain. The frequency difference of the bi-directional laser is controlled by birefringence which is introduced in the ring laser cavity. The beat frequency generated by combining two counter-propagating oscillations is proportional to the birefringence, the fiber ring laser of the present study is, therefore, applicable to the fiber sensor. The sensing signal is obtained in a frequency domain with the material which causes the retardation change by a physical phenomenon to be measured. For the application to stress sensing, the present laser was investigated with a photoelastic material.
基金supported by the National Natural Science Foundation of China(No.12372153)the Funding by Guangdong Basic and Applied Basic Research Foundation(No.2023A1515012366)。
文摘In this study,the free vibration of a piezoelectric semiconductor(PS)composite structure composed of a PS layer,a fractional viscoelastic layer,and an elastic substrate with simply-supported boundary conditions is investigated.The fractional derivative Zener model is used to establish the constitutive relation of the viscoelastic layer.The first-order shear deformation theory and Hamilton's principle are used to derive the motion equations of the present problem.The frequency parameter is numerically resolved with the Newton-Raphson method through the eigenvalue equation.The effects of either geometric parameters,carrier density,and electric voltage applied on the surface of the composite structure or the fractional order of the Zener model on both the natural frequency and loss factor are discussed,and some interesting conclusions are drawn.This work will be helpful for designing and manufacturing PS materials and structures.
基金Project supported by the National Natural Science Foundation of China(Nos.12202039,52204085,and 52474123)。
文摘This paper theoretically investigates the influence of a cylindrical PN junction on the propagation characteristics of shear cylindrical waves(SCWs)in an infinitely long piezoelectric semiconductor(PS)concentric cylinder structure.This PS concentric cylinder structure is composed of three regions:an inner PS cylinder,an outer PS cylindrical shell,and a cylindrical PN junction at the interface between the two aforementioned regions.First,the basic equations of the PS concentric cylinder structure are derived,taking into account the coupling of the mechanical displacement,electric potential,and charge carrier perturbation in the cylindrical coordinate system.Next,a mathematical model for the SCWs in this PS concentric cylinder structure is established,utilizing the spectral method and considering the physical characteristics of the cylindrical PN junction.Finally,the dispersion and attenuation curves of the SCWs are numerically calculated to discuss the influence of the interface effect resulting from the cylindrical PN junction.It is found that the existence of a cylindrical PN junction can either reduce or enhance the mechanical-to-electrical energy conversion,which is closely related to the doping mode,doping concentration,and curvature radius of the cylindrical interface.A reasonable design of the aforementioned parameters can optimize the wave motion in acoustic equipment formed by PS media with different frequencies or wavelengths.The construction and resolution of the mathematical model as well as the analysis of physical mechanisms can offer theoretical guidance for improving the efficiency of energy conversion from mechanical energy to electrical energy and optimizing the acoustic performance of energy harvesting devices.
基金Project supported by the National Natural Science Foundation of China(No.11672265)。
文摘Sandwich piezoelectric semiconductor(PS)structures have significant applications in multi-functional semiconductor devices.The analysis of multi-field coupling behaviors of PS structures is of fundamental importance in developing novel PS devices.In this paper,we develop a general temperature-deformation-polarization-carrier(TDPC)coupling model for sandwich-type PS beams involving pyroelectricity under thermal loadings,based on three-dimensional(3D)basic equations of the thermo-piezoelectric semiconductor(TPS).We derive analytical solutions for extensional,bending,and buckling deformations of simply-supported sandwich n-type PS beams subjected to open-circuit and electrically isolated boundary conditions.The accuracy of the proposed model in this paper is verified through finite element simulations implemented in the COMSOL software.Numerical results show that the initial electron concentration and the thickness ratio of the PS layer to the beam's total thickness have a significant effect on thermally induced extensional and bending responses,as well as critical buckling mechanical and thermal loadings.This study provides a theoretical framework and guidance for designing semiconductor devices based on sandwich PS beam structures.
基金supported by the National Key Research and Development Program of China(No.2023YFE0111000)the National Natural Science Foundation of China(Nos.12372151,12302200,12172171,12172183,and U24A2005)+6 种基金the Natural Science Foundation of Jiangsu Province of China(No.BK20230873)the China Postdoctoral Science Foundation(No.2023M731671)the Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2023ZB156)the Shenzhen Science and Technology Program(No.JCYJ20230807142004009)the Jiangsu Association for Science&Technology Youth Science&Technology Talents Lifting Projectthe Russian Ministry of Science and Higher Education(No.075-15-2023-580)the Shenzhen Longhua Science and Technology Innovation Special Funding(Industrial Sci-Tech Innovation Center of Low-Altitude Intelligent Networking)。
文摘Based on the nonlinear drift-diffusion(NLDD)model,the coupled behavior between the mechanical and electrical fields in piezoelectric semiconductor(PS)PN junctions under two typical loading conditions is investigated.The governing equations for the general shell structure of the PS PN junction are derived within the framework of virtual work principles and charge continuity conditions.The distributions of the electromechanical coupling field are obtained by the Fourier series expansion and the differential quadrature method(DQM),and the nonlinearity is addressed with the iterative method.Several numerical examples are presented to investigate the effects of mechanical loading on the charge carrier transport characteristics.It is found that the barrier height of the heterojunction can be effectively modulated by mechanical loading.Furthermore,a nonlinearity index is introduced to quantify the influence of nonlinearity in the model.It is noted that,when the concentration difference between the two sides is considerable,the nonlinear results differ significantly from the linear results,thereby necessitating the adoption of the NLDD model.
文摘A semiconductor optical amplifier gate based on tensile strained quasi bulk InGaAs is developed.At injection current of 80mA,a 3dB optical bandwidth of more than 85nm is achieved due to dominant band filling effect.Moreover,the most important is that very low polarization dependence of gain (<0 7dB),fiber to fiber lossless operation current (70～90mA) and a high extinction ratio (>50dB) are simultaneously obtained over this wide 3dB optical bandwidth (1520～1609nm) which nearly covers the spectral region of the whole C band (1525～1565nm) and the whole L band (1570～1610nm).The gating time is also improved by decreasing carrier lifetime.The wide band polarization insensitive SOA gate is promising for use in future dense wavelength division multiplexing (DWDM) communication systems.
基金Project supported by the National Natural Science Foundation of China (No. 11802098)the Chinese Postdoctoral Science Foundation (No. 2019M662589)the Natural Science Foundation of Hubei Province of China (No. 2018CFB111)。
文摘Recent success in strain engineering has triggered tremendous interest in its study and potential applications in nanodevice design. In this paper, we establish a coupled piezoelectric/semiconducting model for a wurtzite structure ZnO nanofiber under the local mechanical loading. The energy band structure tuned by the local mechanical loading and local length is calculated via an eight-band k·p method, which includes the coupling of valance and conduction bands. Poisson's effect on the distribution of electric potential inversely depends on the local mechanical loading. Numerical results reveal that both the applied local mechanical loading and the local length exhibit obvious tuning effects on the electric potential and energy band. The band gap at band edges varies linearly with the applied loading. Changing the local length shifts the energy band which is far away from the band edges. This study will be useful in the electronic and optical enhancement of semiconductor devices.
基金supported by the National Natural Science Foundation of China(Nos.12172236 and 12202289)。
文摘Sandwiched functionally-graded piezoelectric semiconductor(FGPS)plates possess high strength and excellent piezoelectric and semiconductor properties,and have significant potential applications in micro-electro-mechanical systems.The multi-field coupling and free vibration of a sandwiched FGPS plate are studied,and the governing equation and natural frequency are derived with the consideration of electron movement.The material properties in the functionally-graded layers are assumed to vary smoothly,and the first-order shear deformation theory is introduced to derive the multi-field coupling in the plate.The total strain energy of the plate is obtained,and the governing equations are presented by using Hamilton’s principle.By introducing the boundary conditions,the coupling physical fields are solved.In numerical examples,the natural frequencies of sandwiched FGPS plates under different geometrical and physical parameters are discussed.It is found that the initial electron density can be used to modulate the natural frequencies and vibrational displacement of sandwiched FGPS plates in the case of nano-size.The effects of the material properties of FGPS layers on the natural frequencies are also examined in detail.
基金National Natural Science Foundation of China(Grant Nos.51972233,52172225)the Science and Technology Commission of Shanghai Municipality(Grant No.19DZ2271500)the Fundamental Research Funds for the Central Universities for funding.
文摘Narrow bandgap semiconductor MgIn_(2)S_(4) has been readily grown onto In_(2)O_(3) nanofibers by an in situ growing method.The so-formed MgIn_(2)S_(4)-In_(2)O_(3) hybrid nanofibers are characterized by strong visible light absorption and intimate MgIn_(2)S_(4)/In_(2)O_(3) heterointerfaces.Under visible light illumination(λ≥400 nm),the hybrid nanofibers demonstrate an exceptionally high photocatalytic activity for Escherichia coli(E.coli)disinfection,outcompeting pristine MgIn_(2)S_(4),naked In_(2)O_(3) nanofibers,and many other photocatalytic systems reported.Specifically,the hybrid nanofibers achieve a 7 log reduction in viable cells for merely 20 min illumination while pristine MgIn_(2)S_(4) and naked In_(2)O_(3) nanofibers alone are almost inactive.Further analysis indicates that the hybrid nanofibers essentially form a type-II semiconductor heterojunctions which enable spatial separation of photocarriers.Owing to the intimate heterointerfaces,photocarriers can be promptly separated and accumulated respectively in In_(2)O_(3) and MgIn_(2)S_(4) thereby allowing continuous generation of copious reactive species for disinfection.This work signifies the usefulness of heterointerfaces in promoting photocarrier separation and provides a useful strategy to upgrade photocatalytic performance from otherwise almost inactive semiconductors.
基金Project supported by the National Natural Science Foundation of China (Nos.12072253 and 62074125)。
文摘Based on the thermo-electro-elastic coupling theory,the mathematical model for a surface heated piezoelectric semiconductor(PS)plate is developed in the time domain.Applying the direct and inverse Laplace transformations to the established model,the mechanical and electrical responses are investigated.The comparison between the analytical solution and the finite element method(FEM)is conducted,which illustrates the validity of the derivation.The calculated results show that the maximum values of the mechanical and electrical fields appear at the heating surface.Importantly,the perturbation carriers tend to concentrate in the zone near the heating surface under the given boundary conditions.It can also be observed that the heating induced elastic wave leads to jumps for the electric potential and perturbation carrier density at the wavefront.When the thermal relaxation time is introduced,all the field quantities become smaller because of the thermal lagging effect.Meanwhile,it can be found that the thermal relaxation time can describe the smooth variation at the jump position.Besides,for a plate with P-N junction,the effect of the interface position on the electrical response is studied.The effects of the initial carrier density on the electrical properties are discussed in detail.The conclusions in this article can be the guidance for the design of PS devices serving in thermal environment.
