Thallium(Tl)compounds,highly toxic to biology,are usually released into flue gas during fossil/minerals combustion,and further distributed in water and soil.In this work,we fundamentally investigated the capture of ga...Thallium(Tl)compounds,highly toxic to biology,are usually released into flue gas during fossil/minerals combustion,and further distributed in water and soil.In this work,we fundamentally investigated the capture of gaseous Tl_(2)O by industrial V2O5-WO3/TiO_(2)catalyst under working condition in Tl-containing flue gas.Experimental and theoretical results indicated that the Tl_(2)O has significant electron-feeding capacity and easily donate electron to unoccupied orbitals of TiO_(2),leading to dismutation of Ti 2p and inartificial formation of p-n junction on TiO_(2)surface,which prompted Tl_(2)O selectively interacted with TiO_(2)in flue gas.Herein,we proposed and verified an effective way to capture gaseous Tl_(2)O,which offered almost the best choice to eliminate Tl emission from flue gas and expanded the function of the TiO_(2)-based catalyst.The formation of p-n junction on commercial V2O5-WO3/TiO_(2)catalyst under working condition was revealed for the first time,which can be a valuable reference for both heterocatalysis and electro/photocatalysis.展开更多
With an extensive range of distinctive features at nano meter-scale thicknesses,two-dimensional(2D)materials drawn the attention of the scientific community.Despite tremendous advancements in exploratory research on 2...With an extensive range of distinctive features at nano meter-scale thicknesses,two-dimensional(2D)materials drawn the attention of the scientific community.Despite tremendous advancements in exploratory research on 2D materials,knowledge of 2D electrical transport and carrier dynamics still in its infancy.Thus,here we highlighted the electrical characteristics of 2D materials with electronic band structure,electronic transport,dielectric constant,carriers mobility.The atomic thinness of 2D materials makes substantially scaled field-effect transistors(FETs)with reduced short-channel effects conceivable,even though strong carrier mobility required for high performance,low-voltage device operations.We also discussed here about factors affecting 2D materials which easily enhanced the activity of those materials for various applications.Presently,Those 2D materials used in state-of-the-art electrical and optoelectronic devices because of the extensive nature of their electronic band structure.2D materials offer unprecedented freedom for the design of novel p-n junction device topologies in contrast to conventional bulk semiconductors.We also,describe the numerous 2D p-n junctions,such as homo junction and hetero junction including mixed dimensional junctions.Finally,we talked about the problems and potential for the future.展开更多
<span style="font-family:Verdana;">A theoretical study of a polysilicon solar cell with a radial junction in </span><span style="font-family:Verdana;">static</span><span ...<span style="font-family:Verdana;">A theoretical study of a polysilicon solar cell with a radial junction in </span><span style="font-family:Verdana;">static</span><span style="font-family:Verdana;"> regime under monochromatic illumination is presented in this paper. The junction radial solar cell geometry is illustrated and described. The carriers’ diffusion equation is established and solved under quasi-neutral base assumption with boundaries conditions and Bessel equations. New analytical expressions of electrons and holes photocurrent density and quantum efficiency are found.</span><span><span><span style="font-family:;" "=""> </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">The wavelength and structural parameters (base radius, </span><span><span style="font-family:Verdana;">base thickness </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> wavelength) influences on photocurrent density and quantum </span></span><span style="font-family:Verdana;">efficiency are carried out and examined.</span></span></span></span>展开更多
Absorption and carrier transport behavior plays an important role in the light-to-electricity conversion process, which is difficult to characterize. Here we develop a method to visualize such a conversion process in ...Absorption and carrier transport behavior plays an important role in the light-to-electricity conversion process, which is difficult to characterize. Here we develop a method to visualize such a conversion process in the InGaN/GaN multiquantum wells embedded in a p-n junction. Under non-resonant absorption conditions, a photocurrent was generated and the photoluminescence intensity decayed by more than 70% when the p-n junction out-circuit was switched from open to short. However, when the excitation photon energy decreased to the resonant absorption edge, the photocurrent dropped drastically and the photoluminescence under open and short circuit conditions showed similar intensity. These results indicate that the escaping of the photo-generated carriers from the quantum wells is closely related to the excitation photon energy.展开更多
Thin films of perovskite manganese oxide Lao.66Ca0.29K0.05MnO3(LCKMO) on Au/ITO(ITO=indium tin oxide) substrates were prepared by off-axis radio frequency magnetron sputtering and characterized by X-ray diffrac- t...Thin films of perovskite manganese oxide Lao.66Ca0.29K0.05MnO3(LCKMO) on Au/ITO(ITO=indium tin oxide) substrates were prepared by off-axis radio frequency magnetron sputtering and characterized by X-ray diffrac- tion(XRD), high-resolution transmission electron microscopy(HRTEM), and conductive atomic force microscopy (C-AFM) at room temperature. The thin films with thickness ranged from 100 nm to 300 nm basically show cubic structures with a=0.3886 nm, the same as that of the raw material used, but the structures are highly modulated. C-AFM results revealed that the atomic scale p-n junction feature of the thin films was the same as that of the single crystals. The preparation of the thin films thus further confirms the possibility of their application extending from micrometer-sized single crystals to macroscopic thin film.展开更多
Porous materials used for humidity sensing have been commercialized.In this paper,the preparation and humidity sensing characteristics of porous silicon with P-N junctions (PNJPS)are studied.PNJPS is made by electro-c...Porous materials used for humidity sensing have been commercialized.In this paper,the preparation and humidity sensing characteristics of porous silicon with P-N junctions (PNJPS)are studied.PNJPS is made by electro-chemical anodic etched method from silicon wafers with P-N junctions.Its porous structure is verified by scanning electronic micrograph. Experiments also show that PNJPS has high sensitivity,short response time (less than 30 seconds),and long-term stability.展开更多
A theoretical study of a polysilicon solar cell with a radial junction in static regime under monochromatic illumination is presented in this paper. The junction radial solar cell geometry is illustrated and described...A theoretical study of a polysilicon solar cell with a radial junction in static regime under monochromatic illumination is presented in this paper. The junction radial solar cell geometry is illustrated and described. The carriers’ diffusion equation is established and solved under quasi-neutral base assumption with boundaries conditions and Bessel equations. New analytical expressions of electrons and holes density and photocurrent are found. The wavelength and structural parameters (base radius, emitter thickness) influences on charge carriers density and photocurrent are shown and examined.展开更多
In this paper, we investigate theoretically a radial n<sup>+</sup>/p silicon solar cell in steady state and monochromatic illumination. The purpose of this work is to analyze the effect of the cell base ra...In this paper, we investigate theoretically a radial n<sup>+</sup>/p silicon solar cell in steady state and monochromatic illumination. The purpose of this work is to analyze the effect of the cell base radius on its electrical parameters. The continuity equation in cylindrical coordinates is established and solved based on Bessel functions and boundaries conditions;this led us to the photovoltage and photocurrent density in the cell. The open circuit voltage and the short circuit current density are then deduced and analyzed considering the base radius. Based on J-V and P-V curves, series and shunt resistances, fill factor and maximum power point are derived and the conversion efficiency of the cell is deduced. We showed that short circuit current density, maximum power, conversion efficiency and shunt resistance decrease with increasing base radius contrary to the open circuit voltage, the fill factor and the series resistance.展开更多
Silicon nanopillars are fabricated by inductively coupled plasma (ICP) dry etching with the cesium chloride (CsCl) islands as masks originally from self-assembly. Wafers with nanopillar texture or planar surface a...Silicon nanopillars are fabricated by inductively coupled plasma (ICP) dry etching with the cesium chloride (CsCl) islands as masks originally from self-assembly. Wafers with nanopillar texture or planar surface are subjected to phosphorus (P) diffusion by liquid dopant source (POCl3) at 870 ℃ to form P-N junctions with a depth of 300 nm. The X-ray photoelectron spectroscopy (XPS) is used to measure the Si 2p core levels of P-N junction wafer with nanopillar texture and planar surface. With a visible light excitation, the P-N junction produces a new electric potential for photoelectric characteristic, which causes the Si 2p core level to have a energy shift compared with the spectrum without the visible light. The energy shift of the Si 2p core level is -0.27 eV for the planar P-N junction and -0.18 eV for the nanopillar one. The difference in Si 2p energy shift is due to more space lattice defects and chemical bond breaks for nanopillar compared with the planar one.展开更多
The p-NiO/n-TiO2/polyaniline composites were synthesized via in situ polymerization of aniline. The structure and morphology of the composites were characterized by means of X-ray diffraction(XRD), scanning electron...The p-NiO/n-TiO2/polyaniline composites were synthesized via in situ polymerization of aniline. The structure and morphology of the composites were characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR) and UV-Vis absorption spectroscopy. It was found that the p-n junction p-NiO/n-TiO2 particles were trapped in the polyaniline molecular matrix and the polyaniline was deposited on the surface of the particles to form a kind of flower cluster morphologies. The electrochemical behavior of the polyaniline composites was investigated. The electrochemical reactivity of the polyaniline was influenced by the p-NiO/n-TiO2 particles due to the effect of electron-hole pairs in these p-n junction particles. The reversibility of redox process and current intensity of the polyaniline composites with the changing of potential scan rate were also discussed.展开更多
ZnO micro-prisms are prepared on the p-type and n-type Si substrates, separately. The Ⅰ-Ⅴ curves analysed by AFM show that the interface junctions between the ZnO micro-prisms and the p-type substrate and between th...ZnO micro-prisms are prepared on the p-type and n-type Si substrates, separately. The Ⅰ-Ⅴ curves analysed by AFM show that the interface junctions between the ZnO micro-prisms and the p-type substrate and between the ZnO micro-prisms and the n-type Si substrate exhibit p-n junction behaviour and ohmic contuct behuviour, respectively. The formation of the p-n heterojunction and ohmic contact is ascribed to the intrinsic n-type conduction of ZnO material. Better field emission performance (lower onset voltage and larger emission current) is observed from an individual ZnO micro-prism grown on the n-type Si substrate. It is suggested that the n-Si/n-ZnO interracial ohmic contact benefits the electron emission; while the p-Si/n-ZnO interface heterojunction deteriorates the electron emission.展开更多
The magnetoresistance effect of a p-n junction under an electric field which is introduced by the gate voltage at room temperature is investigated by simulation. As auxiliary models, the Lombardi CVT model and carrier...The magnetoresistance effect of a p-n junction under an electric field which is introduced by the gate voltage at room temperature is investigated by simulation. As auxiliary models, the Lombardi CVT model and carrier generation- recombination model are introduced into a drift-diffusion transport model and carrier continuity equations. All the equa- tions are discretized by the finite-difference method and the box integration method and then solved by Newton iteration. Taking advantage of those models and methods, an abrupt junction with uniform doping is studied systematically, and the magnetoresistance as a function of doping concentration, SiO2 thickness and geometrical size is also investigated. The simulation results show that the magnetoresistance (MR) can be controlled substantially by the gate and is dependent on the polarity of the magnetic field.展开更多
Monolayer transition-metal dichalcogenides (TMDs) are considered to be fantastic building blocks for a wide variety of optical and optoelectronic devices such as sensors, photodetectors, and quantum emitters, owing ...Monolayer transition-metal dichalcogenides (TMDs) are considered to be fantastic building blocks for a wide variety of optical and optoelectronic devices such as sensors, photodetectors, and quantum emitters, owing to their direct band gap, transparency, and mechanical flexibility. The core element of many conventional electronic and optoelectronic devices is the p-n junction, in which the p- and n-types of the semiconductor are formed by chemical doping in different regions. Here, we report a series of optoelectronic studies on a monolayer WSe2 in-plane p-n photodetector, demonstrating a low- power dissipation by showing an ambipolar behavior with a reduced threshold voltage by a factor of two compared with the previous results on a lateral electrostatically doped WSe2 p-n junction. The fabrication of the device is based on a polycarbonates (PC) transfer technique and hence no electron-beam exposure induced damage to the monolayer WSe2 is expected. Upon optical excitation, the photodetector demonstrates a photoresponsivity of 0.12 mA.W-1 and a maximum external quantum efficiency of 0.03%. Our study provides an alternative platform for a flexible and transparent two- dimensional photodetector, from which we expect to further promote the development of next-generation optoelectronic devices.展开更多
基金financially supported by the National Natural Science Foundation of China(21936005,52070114 and 21876093)Tsinghua-Foshan Innovation Special Fund(TFISF).
文摘Thallium(Tl)compounds,highly toxic to biology,are usually released into flue gas during fossil/minerals combustion,and further distributed in water and soil.In this work,we fundamentally investigated the capture of gaseous Tl_(2)O by industrial V2O5-WO3/TiO_(2)catalyst under working condition in Tl-containing flue gas.Experimental and theoretical results indicated that the Tl_(2)O has significant electron-feeding capacity and easily donate electron to unoccupied orbitals of TiO_(2),leading to dismutation of Ti 2p and inartificial formation of p-n junction on TiO_(2)surface,which prompted Tl_(2)O selectively interacted with TiO_(2)in flue gas.Herein,we proposed and verified an effective way to capture gaseous Tl_(2)O,which offered almost the best choice to eliminate Tl emission from flue gas and expanded the function of the TiO_(2)-based catalyst.The formation of p-n junction on commercial V2O5-WO3/TiO_(2)catalyst under working condition was revealed for the first time,which can be a valuable reference for both heterocatalysis and electro/photocatalysis.
文摘With an extensive range of distinctive features at nano meter-scale thicknesses,two-dimensional(2D)materials drawn the attention of the scientific community.Despite tremendous advancements in exploratory research on 2D materials,knowledge of 2D electrical transport and carrier dynamics still in its infancy.Thus,here we highlighted the electrical characteristics of 2D materials with electronic band structure,electronic transport,dielectric constant,carriers mobility.The atomic thinness of 2D materials makes substantially scaled field-effect transistors(FETs)with reduced short-channel effects conceivable,even though strong carrier mobility required for high performance,low-voltage device operations.We also discussed here about factors affecting 2D materials which easily enhanced the activity of those materials for various applications.Presently,Those 2D materials used in state-of-the-art electrical and optoelectronic devices because of the extensive nature of their electronic band structure.2D materials offer unprecedented freedom for the design of novel p-n junction device topologies in contrast to conventional bulk semiconductors.We also,describe the numerous 2D p-n junctions,such as homo junction and hetero junction including mixed dimensional junctions.Finally,we talked about the problems and potential for the future.
文摘<span style="font-family:Verdana;">A theoretical study of a polysilicon solar cell with a radial junction in </span><span style="font-family:Verdana;">static</span><span style="font-family:Verdana;"> regime under monochromatic illumination is presented in this paper. The junction radial solar cell geometry is illustrated and described. The carriers’ diffusion equation is established and solved under quasi-neutral base assumption with boundaries conditions and Bessel equations. New analytical expressions of electrons and holes photocurrent density and quantum efficiency are found.</span><span><span><span style="font-family:;" "=""> </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">The wavelength and structural parameters (base radius, </span><span><span style="font-family:Verdana;">base thickness </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> wavelength) influences on photocurrent density and quantum </span></span><span style="font-family:Verdana;">efficiency are carried out and examined.</span></span></span></span>
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2016YFB0400302 and 2016YFB0400603)the National Natural Science Foundation of China(Grant Nos.11574362,61210014,and 11374340)the Innovative Clean-Energy Research and Application Program of Beijing Municipal Science and Technology Commission,China(Grant No.Z151100003515001)
文摘Absorption and carrier transport behavior plays an important role in the light-to-electricity conversion process, which is difficult to characterize. Here we develop a method to visualize such a conversion process in the InGaN/GaN multiquantum wells embedded in a p-n junction. Under non-resonant absorption conditions, a photocurrent was generated and the photoluminescence intensity decayed by more than 70% when the p-n junction out-circuit was switched from open to short. However, when the excitation photon energy decreased to the resonant absorption edge, the photocurrent dropped drastically and the photoluminescence under open and short circuit conditions showed similar intensity. These results indicate that the escaping of the photo-generated carriers from the quantum wells is closely related to the excitation photon energy.
基金Supported by the National Natural Science Foundation of China(No.90922034)
文摘Thin films of perovskite manganese oxide Lao.66Ca0.29K0.05MnO3(LCKMO) on Au/ITO(ITO=indium tin oxide) substrates were prepared by off-axis radio frequency magnetron sputtering and characterized by X-ray diffrac- tion(XRD), high-resolution transmission electron microscopy(HRTEM), and conductive atomic force microscopy (C-AFM) at room temperature. The thin films with thickness ranged from 100 nm to 300 nm basically show cubic structures with a=0.3886 nm, the same as that of the raw material used, but the structures are highly modulated. C-AFM results revealed that the atomic scale p-n junction feature of the thin films was the same as that of the single crystals. The preparation of the thin films thus further confirms the possibility of their application extending from micrometer-sized single crystals to macroscopic thin film.
基金National Natural This work was supported Science Foundation of P. R by the China (Grant number: 69666001)West Glory project of Chinese Academy of Science.
文摘Porous materials used for humidity sensing have been commercialized.In this paper,the preparation and humidity sensing characteristics of porous silicon with P-N junctions (PNJPS)are studied.PNJPS is made by electro-chemical anodic etched method from silicon wafers with P-N junctions.Its porous structure is verified by scanning electronic micrograph. Experiments also show that PNJPS has high sensitivity,short response time (less than 30 seconds),and long-term stability.
文摘A theoretical study of a polysilicon solar cell with a radial junction in static regime under monochromatic illumination is presented in this paper. The junction radial solar cell geometry is illustrated and described. The carriers’ diffusion equation is established and solved under quasi-neutral base assumption with boundaries conditions and Bessel equations. New analytical expressions of electrons and holes density and photocurrent are found. The wavelength and structural parameters (base radius, emitter thickness) influences on charge carriers density and photocurrent are shown and examined.
文摘In this paper, we investigate theoretically a radial n<sup>+</sup>/p silicon solar cell in steady state and monochromatic illumination. The purpose of this work is to analyze the effect of the cell base radius on its electrical parameters. The continuity equation in cylindrical coordinates is established and solved based on Bessel functions and boundaries conditions;this led us to the photovoltage and photocurrent density in the cell. The open circuit voltage and the short circuit current density are then deduced and analyzed considering the base radius. Based on J-V and P-V curves, series and shunt resistances, fill factor and maximum power point are derived and the conversion efficiency of the cell is deduced. We showed that short circuit current density, maximum power, conversion efficiency and shunt resistance decrease with increasing base radius contrary to the open circuit voltage, the fill factor and the series resistance.
基金supported by the National Natural Science Foundation of China(Grant No.50972144)
文摘Silicon nanopillars are fabricated by inductively coupled plasma (ICP) dry etching with the cesium chloride (CsCl) islands as masks originally from self-assembly. Wafers with nanopillar texture or planar surface are subjected to phosphorus (P) diffusion by liquid dopant source (POCl3) at 870 ℃ to form P-N junctions with a depth of 300 nm. The X-ray photoelectron spectroscopy (XPS) is used to measure the Si 2p core levels of P-N junction wafer with nanopillar texture and planar surface. With a visible light excitation, the P-N junction produces a new electric potential for photoelectric characteristic, which causes the Si 2p core level to have a energy shift compared with the spectrum without the visible light. The energy shift of the Si 2p core level is -0.27 eV for the planar P-N junction and -0.18 eV for the nanopillar one. The difference in Si 2p energy shift is due to more space lattice defects and chemical bond breaks for nanopillar compared with the planar one.
基金Supported by the National Natural Science Foundation of China(No.51073064)the Science Foundation of Anhui Province, China(No.090414192)
文摘The p-NiO/n-TiO2/polyaniline composites were synthesized via in situ polymerization of aniline. The structure and morphology of the composites were characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR) and UV-Vis absorption spectroscopy. It was found that the p-n junction p-NiO/n-TiO2 particles were trapped in the polyaniline molecular matrix and the polyaniline was deposited on the surface of the particles to form a kind of flower cluster morphologies. The electrochemical behavior of the polyaniline composites was investigated. The electrochemical reactivity of the polyaniline was influenced by the p-NiO/n-TiO2 particles due to the effect of electron-hole pairs in these p-n junction particles. The reversibility of redox process and current intensity of the polyaniline composites with the changing of potential scan rate were also discussed.
文摘ZnO micro-prisms are prepared on the p-type and n-type Si substrates, separately. The Ⅰ-Ⅴ curves analysed by AFM show that the interface junctions between the ZnO micro-prisms and the p-type substrate and between the ZnO micro-prisms and the n-type Si substrate exhibit p-n junction behaviour and ohmic contuct behuviour, respectively. The formation of the p-n heterojunction and ohmic contact is ascribed to the intrinsic n-type conduction of ZnO material. Better field emission performance (lower onset voltage and larger emission current) is observed from an individual ZnO micro-prism grown on the n-type Si substrate. It is suggested that the n-Si/n-ZnO interracial ohmic contact benefits the electron emission; while the p-Si/n-ZnO interface heterojunction deteriorates the electron emission.
文摘The magnetoresistance effect of a p-n junction under an electric field which is introduced by the gate voltage at room temperature is investigated by simulation. As auxiliary models, the Lombardi CVT model and carrier generation- recombination model are introduced into a drift-diffusion transport model and carrier continuity equations. All the equa- tions are discretized by the finite-difference method and the box integration method and then solved by Newton iteration. Taking advantage of those models and methods, an abrupt junction with uniform doping is studied systematically, and the magnetoresistance as a function of doping concentration, SiO2 thickness and geometrical size is also investigated. The simulation results show that the magnetoresistance (MR) can be controlled substantially by the gate and is dependent on the polarity of the magnetic field.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFA0301700)the National Natural Science Foundation of China(Grant Nos.61590932,11774333,61674132,11674300,11575172,and 11625419)+2 种基金the Anhui Provincial Initiative in Quantum Information Technologies,China(Grant Nos.AHY080000 and AHY130300)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB24030601)the Fundamental Research Funds for the Central Universities,China
文摘Monolayer transition-metal dichalcogenides (TMDs) are considered to be fantastic building blocks for a wide variety of optical and optoelectronic devices such as sensors, photodetectors, and quantum emitters, owing to their direct band gap, transparency, and mechanical flexibility. The core element of many conventional electronic and optoelectronic devices is the p-n junction, in which the p- and n-types of the semiconductor are formed by chemical doping in different regions. Here, we report a series of optoelectronic studies on a monolayer WSe2 in-plane p-n photodetector, demonstrating a low- power dissipation by showing an ambipolar behavior with a reduced threshold voltage by a factor of two compared with the previous results on a lateral electrostatically doped WSe2 p-n junction. The fabrication of the device is based on a polycarbonates (PC) transfer technique and hence no electron-beam exposure induced damage to the monolayer WSe2 is expected. Upon optical excitation, the photodetector demonstrates a photoresponsivity of 0.12 mA.W-1 and a maximum external quantum efficiency of 0.03%. Our study provides an alternative platform for a flexible and transparent two- dimensional photodetector, from which we expect to further promote the development of next-generation optoelectronic devices.
基金supported by the National Key R&D Program of China (2022YFB3605500 and 2022YFB3605503)the National Natural Science Foundation of China (62074039 and 12004074)+1 种基金China Postdoctoral Science Foundation (2020M681141)the National Postdoctoral Program for Innovative Talents (BX20190070)。
基金supported by the National Key R&D Program of China(2022YFB3605402 and 2021YFB3601800)the Fundamental Research Funds for the Central Universities+3 种基金the National Natural Science Foundation of China(62274132,62004151,62274126,and 62174123)the Natural Science Basic Research Program of Shaanxi(2021JC24)the Innovation Capability Support Program of Shaanxi(2021TD-04)Wuhu and Xidian University Special Fund for Industry-university-research Cooperation(XWYCXY-012021001 and XWYCXY-012021006)。