As a lightweight nanomaterial,Polyhedral Oligomeric Silsesquioxane(POSS)is widely applied to ablation resistance modification of Ethylene-Propylene-Dine Monomer(EPDM)insulation layer in aerospace propulsion thermal pr...As a lightweight nanomaterial,Polyhedral Oligomeric Silsesquioxane(POSS)is widely applied to ablation resistance modification of Ethylene-Propylene-Dine Monomer(EPDM)insulation layer in aerospace propulsion thermal protection system.However,various structures of POSS can form different crosslinked structures within the EPDM,which can affect the insulation layer properties.Various functionality POSS,Mono-Norbornene POSS(MN-POSS)and TriNorbornene POSS(TN-POSS),were designed and synthesized to obtain crosslinked-modified EPDMs with enhanced mechanical properties and ablation resistance simultaneously,and the relationship between POSS functionality,the mechanical properties,ablation resistance,heat-shielding and thermal decomposition of EPDM/Aramid Fiber(AF)composites were explored comprehensively.MN-POSS and TN-POSS increased the tensile strength of EPDM composites by 25.3%and 75.2%respectively,reduced the linear ablation rate by 37.7%and 33.7%respectively,and reduced the back temperatures by 3.9℃ and 3.3℃ respectively.Under conditions of equal cage structure(T8),the suspended crosslinked structure caused by MN-POSS exhibited better ablation resistance and heat-shielding performance as well as thermal decomposition,and the anchored crosslinked structure caused by TN-POSS exhibited better tensile strength.The structural transformation indicates that the POSS nanocages can be transformed into a ceramic structure in cruel environments to resist the erosion of heat flow and enhance the ablation resistance of insulation layer.展开更多
The oxidation behavior of different SiAlON phases（β-SiAlON,X-phase SiAlON and 12H powders） synthesized from coal gangue in air atmosphere was investigated using isothermal thermogravimetry（TG） and field-emission ...The oxidation behavior of different SiAlON phases（β-SiAlON,X-phase SiAlON and 12H powders） synthesized from coal gangue in air atmosphere was investigated using isothermal thermogravimetry（TG） and field-emission scanning electron microscopy（FE-SEM）.The effect of ferric oxide impurities in coal gangue was studied.The results show that ferric oxide contributes to the growth of SiAlON crystalline during the synthesis process.In the oxidation experiment,the existence of ferric oxide decreases the oxidation resistance of SiAlON.The reason is that the impurity causes the formation of a liquid phase at a higher temperature.At 1423-1623 K,the oxidation of SiAlON powders is diffusion controlled and it can be described by Chou＇s model.A fair agreement is found between theoretical calculations and the experimental data.展开更多
In the present work,a stable two-dimensional(2D)P_(2)Si monolayer was predicted.The monolayer is semimetallic/metallic under the PBE/HSE06 functional and is mechanically isotropic.The stability of the P_(2)Si monolaye...In the present work,a stable two-dimensional(2D)P_(2)Si monolayer was predicted.The monolayer is semimetallic/metallic under the PBE/HSE06 functional and is mechanically isotropic.The stability of the P_(2)Si monolayer has been proved via cohesive energy,mechanical criteria,molecular dynamics simulation,and phonon dispersion respectively,and the monolayer possesses high carrier mobility which is three times that of Mo S_(2).On the other hand,the catalytic performance of the P_(2)Si monolayer modified with a single transition metals(M=Sc-Cu)atom for the electrochemical reduction of CO_(2)was investigated,and the monolayer can catalyze CO_(2)with three constraints:stable molecular dynamics,high migration potential of metal atoms,and suitable band gap for electrocatalyst after metal doping exhibiting excellent catalytic stabilization activity and CRR selectivity.In addition,the reduction product of V@P_(2)Si is HCOOH with an overpotential as low as 0.75 V,and the most suitable reaction path is^(*)CO_(2)→^(*)CHOO→O^(*)CHOH→^(*)+HCOOH with the final reduction product HCOOH obtained.As a whole,the above results endow the P_(2)Si monolayer to be a good 2D material holding great promises for applications in nanoelectronics and CO_(2)reduction catalysts.展开更多
Sputtering deposition coatings offer significant advantages on electron beam (EB) deposition, including high packing density, environmental stability and extremely low losses. But the inherent high compressive stress ...Sputtering deposition coatings offer significant advantages on electron beam (EB) deposition, including high packing density, environmental stability and extremely low losses. But the inherent high compressive stress affects its application in high power laser system. This paper describes the technical feasibility of high damage threshold laser mirrors deposited by a novel remote plasma sputtering technique. This technique is based on generating intensive plasma remotely from the target and then magnetically steering the plasma to the target to realize the full uniform sputtering. The pseudo-independence between target voltage and target current provides us very flexible parameters tuning, especially for the films stress control. Deposition conditions are optimized to yield fully oxidized and low compressive stress single layer HfO2 and SiO2. The high damage threshold of 43.8 J/cm2 for HfO2/ SiO2 laser mirrors at 1064 nm is obtained. For the first time the remote plasma sputtering is successfully applied in depositing laser mirrors with high performance.展开更多
A new kind of glass-ceramic phosphor, which contains crystalline phases with green emissions, is explored. The glassceramic is prepared through semi-melt-quenching procedure with a nominal composition of （Ca0.99Eu0.0...A new kind of glass-ceramic phosphor, which contains crystalline phases with green emissions, is explored. The glassceramic is prepared through semi-melt-quenching procedure with a nominal composition of （Ca0.99Eu0.01）3Si2O7. The greenemitting crystals are precipitated and identified to be β-Ca2SiO4： Eu2＋ which is responsible for 510 nm-peaked much broader band emissions holding at 1550 ℃ for half an hour. In terms of the available light scattering theory, the appearance of opaque is discussed by closely associating with size and morphology of luminous β-Ca2SiO4 crystalline phase in glass.展开更多
A hexagonal solid-core bismuth-oxide micro-structure fiber is developed to balance its dispersion and nonlinearity.This simulation and calculation results show that the bismuth-oxide photonic crystal fiber(Bi-PCF) has...A hexagonal solid-core bismuth-oxide micro-structure fiber is developed to balance its dispersion and nonlinearity.This simulation and calculation results show that the bismuth-oxide photonic crystal fiber(Bi-PCF) has near zero dispersion around 1550 nm.Its dispersion slop in the communication wavelength range is also relatively flat.Moreover,both nonlinear coefficient and model field distribution are obtained.Compared with the experimental results by SiO2-PCF,it can be seen that the Bi-PCF shows excellent characteristics for the optical parametric amplification(OPA).展开更多
We demonstrate a novel SOI-based photonic crystal（PC） double-heterostructure slot waveguide microcavity constructed by cascading three PC slot waveguides with different slot widths,and simulate the luminescence enha...We demonstrate a novel SOI-based photonic crystal（PC） double-heterostructure slot waveguide microcavity constructed by cascading three PC slot waveguides with different slot widths,and simulate the luminescence enhancement of sol-gel Er-doped SiO2 filled in the microcavity by finite-difference time-domain（FDTD） method.The calculated results indicate that a unique sharp resonant peak dominates in the spectrum at the expected telecommunication wavelength of 1.5509 mm,with very high normalized peak intensity of ~108.The electromagnetic field of the resonant mode exhibits the strongest in the microcavity,and decays rapidly to zero along both sides,which means that the resonant mode field is well confined in the microcavity.The simulation results fully verify the enhancement of luminescence by PC double-heterostructure slot waveguide microcavity theoretically,which is a promising way to realize the high-efficiency luminescence of Si-based materials.展开更多
Based on the technology of low temperature poly silicon thin film transistors (poly-Si-TFTs), a novel p-type TFT AMOLED panel with self-scanned driving circuit is introduced in this paper. A shift register formed with...Based on the technology of low temperature poly silicon thin film transistors (poly-Si-TFTs), a novel p-type TFT AMOLED panel with self-scanned driving circuit is introduced in this paper. A shift register formed with novel p-type TFTs is pro- posed to realize the gate driver. A flip-latch cooperated with the shift register is designed to conduct the data writing. In order to verify the validity of the proposed design, the circuits are simulated with SILVACO TCAD tools, using the MODEL in which the paramete...展开更多
Silicon belongs to group 14 elements along with carbon,germanium,tin,and lead in the periodic table.Similar to carbon,silicon is capable of forming a wide range of stable compounds,including silicon hydrides,organosil...Silicon belongs to group 14 elements along with carbon,germanium,tin,and lead in the periodic table.Similar to carbon,silicon is capable of forming a wide range of stable compounds,including silicon hydrides,organosilicons,silicic acids,silicon oxides,and silicone polymers.These materials have been used extensively in optoelectronic devices,sensing,catalysis,and biomedical applications.In recent years,silicon compounds have also been shown to be suitable for stabilizing delicate halide perovskite structures.These composite materials are now receiving a lot of interest for their potential use in various real-world applications.Despite exhibiting outstanding performance in various optoelectronic devices,halide perovskites are susceptible to breakdown in the presence of moisture,oxygen,heat,and UV light.Silicon compounds are thought to be excellent materials for improving both halide perovskite stability and the performance of perovskite-based optoelectronic devices.In this work,a wide range of silicon compounds that have been used in halide perovskite research and their applications in various fields are discussed.The interfacial stability,structure-property correlations,and various application aspects of perovskite and silicon compounds are also analyzed at the molecular level.This study also explores the developments,difficulties,and potential future directions associated with the synthesis and application of perovskite-silicon compounds.展开更多
SiOx （x = 0-2） films were deposited on BK-7 substrates by a low frequency reactive magnetron sputtering system with the oxygen flow rate （OFR） changing from 0 to 30 sccm. The samples were characterized by atomic f...SiOx （x = 0-2） films were deposited on BK-7 substrates by a low frequency reactive magnetron sputtering system with the oxygen flow rate （OFR） changing from 0 to 30 sccm. The samples were characterized by atomic force microscopy, spectrophotometer, and X-ray photoelectron spectroscopy. The extinction coefficient and refractive index decrease, while the optical transmittance increases with the increase of OFR from 0 to 17 sccm. The root mean square surface roughness has a maximum at 10 sccm OFR. The highest deposition rate is at 15 sccm OFR. Our results show that the films deposited at 20 sccm OFR are stoichiometric silica with relatively high deposition rate, low extinction coefficient, and low surface roughness. Therefore, a precise control of OFR is very important to obtain high quality films for optical applications.展开更多
A numerical model is developed for the calculation of transient temperature field of thin film coating induced by a long-pulsed high power laser beam. The electric field intensity distribution of HfO2/Si02 high reflec...A numerical model is developed for the calculation of transient temperature field of thin film coating induced by a long-pulsed high power laser beam. The electric field intensity distribution of HfO2/Si02 high reflective （HR） film is investigated to calculate the thermal field of the film. The thermal-mechanical relationships are discussed to predict the laser damage area of optical thin film under long pulse high energy laser irradiation.展开更多
The evolution of stress in evaporated SiO2, used as optical coatings, is investigated experimentally through in situ stress measurement. A typical evolution pattern consisting of five subprocedures （thin film deposit...The evolution of stress in evaporated SiO2, used as optical coatings, is investigated experimentally through in situ stress measurement. A typical evolution pattern consisting of five subprocedures （thin film deposition, stopping deposition, cooling, venting the vacuum chamber, and exposing coated optics to the atmosphere） is put forward. Further investigations into the subprocedures reveal their features. During the deposition stage, the stresses are usually compressive and reach a stable state when the deposited film is thicker than 100 nm. An increment of compressive stress value is observed with the decrease of residual gas pressure or deposition rate. A very low stress of-20 MPa is formed in SiO2 films deposited at 3×10^-2 Pa. After deposition, the stress increases slightly in the compressive direction and is subject to the stabilization in subsequent tens of minutes. In the process of venting and exposure, the compressive component increases rapidly with the admission of room air and then reaches saturation, followed by a logarithmic decrement of the compressive state in the succeeding hours. An initial discussion of these behaviors is given.展开更多
A new method for increasing laser induced damage threshold （LIDT） of dielectric antireflection （AR） coating is proposed. Compared with AR film stack of H2.5L （H：HfO2, L：SiO2） on BK7 substrate, SiO2 interracial...A new method for increasing laser induced damage threshold （LIDT） of dielectric antireflection （AR） coating is proposed. Compared with AR film stack of H2.5L （H：HfO2, L：SiO2） on BK7 substrate, SiO2 interracial layer with four quarter wavelength optical thickness （QWOT） is deposited on the substrate before the preparation of H2.5L film. It is found that the introduction of SiO2 interfacial layer with a certain thickness is effective and flexible to increase the LIDT of dielectric AR coatings. The measured LIDT is enhanced by about 50%, while remaining the low reflectivity with less than 0.09% at the center wavelength of 1064 nm. Detailed mechanisms of the LIDT enhancement are discussed.展开更多
Guided mode resonant filters （GMRFs） for authentication application with low sideband reflection at 0^o and 90^o azimuthal angles were designed. Using rigorous coupled-wave analysis, the diffractive characteristics ...Guided mode resonant filters （GMRFs） for authentication application with low sideband reflection at 0^o and 90^o azimuthal angles were designed. Using rigorous coupled-wave analysis, the diffractive characteristics of this kind device with different illumination angles, groove depths, and thicknesses of cover SiO2 layer were investigated. The structure of GMRF which satisfies the requirements for authentication applications was obtained. Illuminated at 30^o for a definite polarization mode, the filter presents symmetrical reflectance shape, low sideband reflectance, two separate reflectance peaks, and definite full-width at halfmaximum （FWHM） at 0^o and 90^o azimuthal angles.展开更多
The performances of HfO2/SiO2 single- and multi-layer coatings in vacuum influenced by contamination are studied. The surface morphology, the transmittance spectrum, and the laser-induced damage threshold are investig...The performances of HfO2/SiO2 single- and multi-layer coatings in vacuum influenced by contamination are studied. The surface morphology, the transmittance spectrum, and the laser-induced damage threshold are investigated. The results show that the contamination in vacuum mainly comes from the vacuum system and the contamination process is different for the HfO2 and SiO2 films. The laser-induced damage experiments at 1064 nm in vacuum show that the damage resistance of the coatings will decrease largely due to the organic contamination.展开更多
Nondestructive Raman spectroscopy and external-beam proton-induced X-ray emission （PIXE） technique to analyze eight ancient glasses unearthed from the provinces of Henan,Hubei,and Jiangsu,which allowes for a good ch...Nondestructive Raman spectroscopy and external-beam proton-induced X-ray emission （PIXE） technique to analyze eight ancient glasses unearthed from the provinces of Henan,Hubei,and Jiangsu,which allowes for a good characterization of the glass matrix and chemical compositions,is carried out.The results indicate that all the eight glass samples could be typically divided into three systems： faience （sample No.SZWG-4）,PbO-BaO-SiO 2 （sample Nos.NYWKI-5-1,HNWKII-88,and HNWKII-84）,and Na 2 OCaO-SiO 2 （sample Nos.HBWKI-16,HBWKI-17,HBWKI-18,and SZWG-1）.Additional relationships between the Raman spectra and parameters,such as residues of raw materials and opacifying agent,are also discussed by respectively comparing them with similar glass samples excavated from other historical sites.展开更多
Low-voltage silicon （Si）-based light-emitting diode （LED） is designed based on the former research of LED in Si-based standard complementary metal oxide semiconductor （CMOS） technology. The low-voltage LED is de...Low-voltage silicon （Si）-based light-emitting diode （LED） is designed based on the former research of LED in Si-based standard complementary metal oxide semiconductor （CMOS） technology. The low-voltage LED is designed under the research of cross-finger structure LEDs and sophisticated structure enhanced LEDs for high efficiency and stable light source of monolithic chip integration. The device size of low-voltage LED is 45.85x38.4 （#m）, threshold voltage is 2.2 V in common condition, and temperature is 27 ~C. The external quantum efficiency is about 10-6 at stable operating state of 5 V and 177 mA.展开更多
The method of fitting damage probability curves of laser-induced damage is introduced to investigate the laser-conditioning mechanism of ZrO2/SiO2 high reflection（HR） films.The laser-induced damage thresholds（LIDTs...The method of fitting damage probability curves of laser-induced damage is introduced to investigate the laser-conditioning mechanism of ZrO2/SiO2 high reflection（HR） films.The laser-induced damage thresholds（LIDTs） of the sample are tested before and after the laser-conditioning scanning process.The parameters of the defects are obtained through the fitting process of the damage probability curve.It can be concluded that the roles of laser conditioning include two aspects：removing defects with lower threshold and producing new defects with higher threshold.The effect of laser conditioning is dependent on the competition of these two aspects.展开更多
Ta2O5 and Nb2O5 films are deposited on BK7 glass substrates using an electron beam evaporation method and are annealed at 673 K in the air. In this letter, comparative studies of the optical transmittance, microstruct...Ta2O5 and Nb2O5 films are deposited on BK7 glass substrates using an electron beam evaporation method and are annealed at 673 K in the air. In this letter, comparative studies of the optical transmittance, microstructure, chemical composition, optical absorption, and laser-induced damage threshold （LIDT） of the two films are conducted. Findings indicate that the substoichiometric defect is very harmful to the laser damage resistance of Ta2O5 and Nb2O5 films. The decrease of absorption improves the LIDT in films deposited by the same material. However, although the absorption of the Ta2O5 single layer is less than that of the Nb2O5 single layer, the LIDT of the former is lower than that of the latter. High-reflective （HR） coatings have a higher LIDT than single layers due to the thermal dissipation of the SiO2 layers and the decreased electric field intensity （EFI）. In addition, the Nb2O5 HR coating achieves the highest LIDT at 25.6 J/cm^2 in both single layers and HR coatings.展开更多
HfO2 and SiO2 single layer is deposited on glass substrate with plasma ion assistance provided by Leybold advanced plasma source （APS）. The deposition is performed with a bias voltage in the range of 70-130 V for Hf...HfO2 and SiO2 single layer is deposited on glass substrate with plasma ion assistance provided by Leybold advanced plasma source （APS）. The deposition is performed with a bias voltage in the range of 70-130 V for HfO2, and 70-170 V for SiO2. Optical, structural, mechanical properties, as well as absorption and laser induced damage threshold at 1064 nm of HfO2 and SiO2 single layer deposited with the plasma ion assistance are systematically investigated. With the increase of APS bias voltage, coatings with higher refractive index, reduced surface roughness, and higher laser-induced damage threshold （LIDT） are obtained, and no significant change of the absorption at 1064 nm is observed. For HfO2, a bias voltage can be identified to achieve coatings without any stress. However, too-high bias voltage can cause the increase of surface roughness and stress, and decrease the LIDT. The bias voltage can be properly identified to achieve coatings with desired properties.展开更多
基金the support from the Xianyang Major Scientific and Technological Innovation Special Project—University and Research Institute“Three-Item Reform”Technology Transfer Project,China(No.D5140240003)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University,China(No.CX2023093)。
文摘As a lightweight nanomaterial,Polyhedral Oligomeric Silsesquioxane(POSS)is widely applied to ablation resistance modification of Ethylene-Propylene-Dine Monomer(EPDM)insulation layer in aerospace propulsion thermal protection system.However,various structures of POSS can form different crosslinked structures within the EPDM,which can affect the insulation layer properties.Various functionality POSS,Mono-Norbornene POSS(MN-POSS)and TriNorbornene POSS(TN-POSS),were designed and synthesized to obtain crosslinked-modified EPDMs with enhanced mechanical properties and ablation resistance simultaneously,and the relationship between POSS functionality,the mechanical properties,ablation resistance,heat-shielding and thermal decomposition of EPDM/Aramid Fiber(AF)composites were explored comprehensively.MN-POSS and TN-POSS increased the tensile strength of EPDM composites by 25.3%and 75.2%respectively,reduced the linear ablation rate by 37.7%and 33.7%respectively,and reduced the back temperatures by 3.9℃ and 3.3℃ respectively.Under conditions of equal cage structure(T8),the suspended crosslinked structure caused by MN-POSS exhibited better ablation resistance and heat-shielding performance as well as thermal decomposition,and the anchored crosslinked structure caused by TN-POSS exhibited better tensile strength.The structural transformation indicates that the POSS nanocages can be transformed into a ceramic structure in cruel environments to resist the erosion of heat flow and enhance the ablation resistance of insulation layer.
基金supported by the National Natural Science Foundation of China(No.50874013)the support from the Key Lab. of the Ministry of Education of China for Ecologic & Recycle Metallurgy,University of Science and Technology Beijing
文摘The oxidation behavior of different SiAlON phases（β-SiAlON,X-phase SiAlON and 12H powders） synthesized from coal gangue in air atmosphere was investigated using isothermal thermogravimetry（TG） and field-emission scanning electron microscopy（FE-SEM）.The effect of ferric oxide impurities in coal gangue was studied.The results show that ferric oxide contributes to the growth of SiAlON crystalline during the synthesis process.In the oxidation experiment,the existence of ferric oxide decreases the oxidation resistance of SiAlON.The reason is that the impurity causes the formation of a liquid phase at a higher temperature.At 1423-1623 K,the oxidation of SiAlON powders is diffusion controlled and it can be described by Chou＇s model.A fair agreement is found between theoretical calculations and the experimental data.
基金funded by the Natural Science Foundation of China(Nos.21603109,11304128)the Henan Joint Fund of the National Natural Science Foundation of China(No.U1404216)+1 种基金the Science and Technology Program of Henan Department of Science and Technology,China(No.182102310609)the Construct Program of Applied Characteristic Discipline in Hunan University of Science and Engineering(Mathematics,Education and Electronic Science and Technology)。
文摘In the present work,a stable two-dimensional(2D)P_(2)Si monolayer was predicted.The monolayer is semimetallic/metallic under the PBE/HSE06 functional and is mechanically isotropic.The stability of the P_(2)Si monolayer has been proved via cohesive energy,mechanical criteria,molecular dynamics simulation,and phonon dispersion respectively,and the monolayer possesses high carrier mobility which is three times that of Mo S_(2).On the other hand,the catalytic performance of the P_(2)Si monolayer modified with a single transition metals(M=Sc-Cu)atom for the electrochemical reduction of CO_(2)was investigated,and the monolayer can catalyze CO_(2)with three constraints:stable molecular dynamics,high migration potential of metal atoms,and suitable band gap for electrocatalyst after metal doping exhibiting excellent catalytic stabilization activity and CRR selectivity.In addition,the reduction product of V@P_(2)Si is HCOOH with an overpotential as low as 0.75 V,and the most suitable reaction path is^(*)CO_(2)→^(*)CHOO→O^(*)CHOH→^(*)+HCOOH with the final reduction product HCOOH obtained.As a whole,the above results endow the P_(2)Si monolayer to be a good 2D material holding great promises for applications in nanoelectronics and CO_(2)reduction catalysts.
基金supported by the National Natural Science Foundation of China (No. 50802080)the Natural Science Foundation of Fujian Province of China (No.2010Jo1349)
文摘Sputtering deposition coatings offer significant advantages on electron beam (EB) deposition, including high packing density, environmental stability and extremely low losses. But the inherent high compressive stress affects its application in high power laser system. This paper describes the technical feasibility of high damage threshold laser mirrors deposited by a novel remote plasma sputtering technique. This technique is based on generating intensive plasma remotely from the target and then magnetically steering the plasma to the target to realize the full uniform sputtering. The pseudo-independence between target voltage and target current provides us very flexible parameters tuning, especially for the films stress control. Deposition conditions are optimized to yield fully oxidized and low compressive stress single layer HfO2 and SiO2. The high damage threshold of 43.8 J/cm2 for HfO2/ SiO2 laser mirrors at 1064 nm is obtained. For the first time the remote plasma sputtering is successfully applied in depositing laser mirrors with high performance.
基金supported by the National Natural Science Foundation of China(Nos.50872091 and 21076161)the Key Discipline of Materials Physics and Chemistry of Tianjin(Nos.2006ZD30 and 10SYSYJC28100)
文摘A new kind of glass-ceramic phosphor, which contains crystalline phases with green emissions, is explored. The glassceramic is prepared through semi-melt-quenching procedure with a nominal composition of （Ca0.99Eu0.01）3Si2O7. The greenemitting crystals are precipitated and identified to be β-Ca2SiO4： Eu2＋ which is responsible for 510 nm-peaked much broader band emissions holding at 1550 ℃ for half an hour. In terms of the available light scattering theory, the appearance of opaque is discussed by closely associating with size and morphology of luminous β-Ca2SiO4 crystalline phase in glass.
基金supported by the"973" Project of China (No.2010CB328300)
文摘A hexagonal solid-core bismuth-oxide micro-structure fiber is developed to balance its dispersion and nonlinearity.This simulation and calculation results show that the bismuth-oxide photonic crystal fiber(Bi-PCF) has near zero dispersion around 1550 nm.Its dispersion slop in the communication wavelength range is also relatively flat.Moreover,both nonlinear coefficient and model field distribution are obtained.Compared with the experimental results by SiO2-PCF,it can be seen that the Bi-PCF shows excellent characteristics for the optical parametric amplification(OPA).
基金supported by the National Key Basic Research Special Fund of China (No.2007CB613404)the National High Technology,Research and Development Program of China (No.2011AA010303)the National Natural Science Foundation of China (Nos.61090390,60837001,60977045,60877014 and 60776057)
文摘We demonstrate a novel SOI-based photonic crystal（PC） double-heterostructure slot waveguide microcavity constructed by cascading three PC slot waveguides with different slot widths,and simulate the luminescence enhancement of sol-gel Er-doped SiO2 filled in the microcavity by finite-difference time-domain（FDTD） method.The calculated results indicate that a unique sharp resonant peak dominates in the spectrum at the expected telecommunication wavelength of 1.5509 mm,with very high normalized peak intensity of ~108.The electromagnetic field of the resonant mode exhibits the strongest in the microcavity,and decays rapidly to zero along both sides,which means that the resonant mode field is well confined in the microcavity.The simulation results fully verify the enhancement of luminescence by PC double-heterostructure slot waveguide microcavity theoretically,which is a promising way to realize the high-efficiency luminescence of Si-based materials.
基金supported by the National Natural ScienceFoundation of China(Grant No.60437030)
文摘Based on the technology of low temperature poly silicon thin film transistors (poly-Si-TFTs), a novel p-type TFT AMOLED panel with self-scanned driving circuit is introduced in this paper. A shift register formed with novel p-type TFTs is pro- posed to realize the gate driver. A flip-latch cooperated with the shift register is designed to conduct the data writing. In order to verify the validity of the proposed design, the circuits are simulated with SILVACO TCAD tools, using the MODEL in which the paramete...
基金National Research Foundation of Korea,Grant/Award Numbers:2021R1F1A1062528,2021R1A4A5031805,2021R1A2C1006113,BrainLink RS-2023-00236798。
文摘Silicon belongs to group 14 elements along with carbon,germanium,tin,and lead in the periodic table.Similar to carbon,silicon is capable of forming a wide range of stable compounds,including silicon hydrides,organosilicons,silicic acids,silicon oxides,and silicone polymers.These materials have been used extensively in optoelectronic devices,sensing,catalysis,and biomedical applications.In recent years,silicon compounds have also been shown to be suitable for stabilizing delicate halide perovskite structures.These composite materials are now receiving a lot of interest for their potential use in various real-world applications.Despite exhibiting outstanding performance in various optoelectronic devices,halide perovskites are susceptible to breakdown in the presence of moisture,oxygen,heat,and UV light.Silicon compounds are thought to be excellent materials for improving both halide perovskite stability and the performance of perovskite-based optoelectronic devices.In this work,a wide range of silicon compounds that have been used in halide perovskite research and their applications in various fields are discussed.The interfacial stability,structure-property correlations,and various application aspects of perovskite and silicon compounds are also analyzed at the molecular level.This study also explores the developments,difficulties,and potential future directions associated with the synthesis and application of perovskite-silicon compounds.
基金This work was supported by the National Natural Sci-ence Foundation of China under Grant No. 50121202and 10174073
文摘SiOx （x = 0-2） films were deposited on BK-7 substrates by a low frequency reactive magnetron sputtering system with the oxygen flow rate （OFR） changing from 0 to 30 sccm. The samples were characterized by atomic force microscopy, spectrophotometer, and X-ray photoelectron spectroscopy. The extinction coefficient and refractive index decrease, while the optical transmittance increases with the increase of OFR from 0 to 17 sccm. The root mean square surface roughness has a maximum at 10 sccm OFR. The highest deposition rate is at 15 sccm OFR. Our results show that the films deposited at 20 sccm OFR are stoichiometric silica with relatively high deposition rate, low extinction coefficient, and low surface roughness. Therefore, a precise control of OFR is very important to obtain high quality films for optical applications.
文摘A numerical model is developed for the calculation of transient temperature field of thin film coating induced by a long-pulsed high power laser beam. The electric field intensity distribution of HfO2/Si02 high reflective （HR） film is investigated to calculate the thermal field of the film. The thermal-mechanical relationships are discussed to predict the laser damage area of optical thin film under long pulse high energy laser irradiation.
基金supported by the National Natural Science Foundation of China under Grant No.10704078
文摘The evolution of stress in evaporated SiO2, used as optical coatings, is investigated experimentally through in situ stress measurement. A typical evolution pattern consisting of five subprocedures （thin film deposition, stopping deposition, cooling, venting the vacuum chamber, and exposing coated optics to the atmosphere） is put forward. Further investigations into the subprocedures reveal their features. During the deposition stage, the stresses are usually compressive and reach a stable state when the deposited film is thicker than 100 nm. An increment of compressive stress value is observed with the decrease of residual gas pressure or deposition rate. A very low stress of-20 MPa is formed in SiO2 films deposited at 3×10^-2 Pa. After deposition, the stress increases slightly in the compressive direction and is subject to the stabilization in subsequent tens of minutes. In the process of venting and exposure, the compressive component increases rapidly with the admission of room air and then reaches saturation, followed by a logarithmic decrement of the compressive state in the succeeding hours. An initial discussion of these behaviors is given.
文摘A new method for increasing laser induced damage threshold （LIDT） of dielectric antireflection （AR） coating is proposed. Compared with AR film stack of H2.5L （H：HfO2, L：SiO2） on BK7 substrate, SiO2 interracial layer with four quarter wavelength optical thickness （QWOT） is deposited on the substrate before the preparation of H2.5L film. It is found that the introduction of SiO2 interfacial layer with a certain thickness is effective and flexible to increase the LIDT of dielectric AR coatings. The measured LIDT is enhanced by about 50%, while remaining the low reflectivity with less than 0.09% at the center wavelength of 1064 nm. Detailed mechanisms of the LIDT enhancement are discussed.
基金the National Basic Research Program of China(No.2007CB935303)the Shanghai Committee of Science and Technology(No.06DZ22016 and 07DZ22026)
文摘Guided mode resonant filters （GMRFs） for authentication application with low sideband reflection at 0^o and 90^o azimuthal angles were designed. Using rigorous coupled-wave analysis, the diffractive characteristics of this kind device with different illumination angles, groove depths, and thicknesses of cover SiO2 layer were investigated. The structure of GMRF which satisfies the requirements for authentication applications was obtained. Illuminated at 30^o for a definite polarization mode, the filter presents symmetrical reflectance shape, low sideband reflectance, two separate reflectance peaks, and definite full-width at halfmaximum （FWHM） at 0^o and 90^o azimuthal angles.
文摘The performances of HfO2/SiO2 single- and multi-layer coatings in vacuum influenced by contamination are studied. The surface morphology, the transmittance spectrum, and the laser-induced damage threshold are investigated. The results show that the contamination in vacuum mainly comes from the vacuum system and the contamination process is different for the HfO2 and SiO2 films. The laser-induced damage experiments at 1064 nm in vacuum show that the damage resistance of the coatings will decrease largely due to the organic contamination.
基金supported by the National Natural Science Foundation of China under Grant No.51072206
文摘Nondestructive Raman spectroscopy and external-beam proton-induced X-ray emission （PIXE） technique to analyze eight ancient glasses unearthed from the provinces of Henan,Hubei,and Jiangsu,which allowes for a good characterization of the glass matrix and chemical compositions,is carried out.The results indicate that all the eight glass samples could be typically divided into three systems： faience （sample No.SZWG-4）,PbO-BaO-SiO 2 （sample Nos.NYWKI-5-1,HNWKII-88,and HNWKII-84）,and Na 2 OCaO-SiO 2 （sample Nos.HBWKI-16,HBWKI-17,HBWKI-18,and SZWG-1）.Additional relationships between the Raman spectra and parameters,such as residues of raw materials and opacifying agent,are also discussed by respectively comparing them with similar glass samples excavated from other historical sites.
基金supported by the National Natural Science Foundation of China(Nos.61036002,60536030, 60776024,60877035,61076023,and 90820002)the National "863" Program of China(Nos.2007AA04Z329, 2007AA04Z254,2011CB933203,and 2011CB933102)
文摘Low-voltage silicon （Si）-based light-emitting diode （LED） is designed based on the former research of LED in Si-based standard complementary metal oxide semiconductor （CMOS） technology. The low-voltage LED is designed under the research of cross-finger structure LEDs and sophisticated structure enhanced LEDs for high efficiency and stable light source of monolithic chip integration. The device size of low-voltage LED is 45.85x38.4 （#m）, threshold voltage is 2.2 V in common condition, and temperature is 27 ~C. The external quantum efficiency is about 10-6 at stable operating state of 5 V and 177 mA.
文摘The method of fitting damage probability curves of laser-induced damage is introduced to investigate the laser-conditioning mechanism of ZrO2/SiO2 high reflection（HR） films.The laser-induced damage thresholds（LIDTs） of the sample are tested before and after the laser-conditioning scanning process.The parameters of the defects are obtained through the fitting process of the damage probability curve.It can be concluded that the roles of laser conditioning include two aspects：removing defects with lower threshold and producing new defects with higher threshold.The effect of laser conditioning is dependent on the competition of these two aspects.
基金supported by the Fundamental Research Funds for the Central Universities under Grant No.2009A058
文摘Ta2O5 and Nb2O5 films are deposited on BK7 glass substrates using an electron beam evaporation method and are annealed at 673 K in the air. In this letter, comparative studies of the optical transmittance, microstructure, chemical composition, optical absorption, and laser-induced damage threshold （LIDT） of the two films are conducted. Findings indicate that the substoichiometric defect is very harmful to the laser damage resistance of Ta2O5 and Nb2O5 films. The decrease of absorption improves the LIDT in films deposited by the same material. However, although the absorption of the Ta2O5 single layer is less than that of the Nb2O5 single layer, the LIDT of the former is lower than that of the latter. High-reflective （HR） coatings have a higher LIDT than single layers due to the thermal dissipation of the SiO2 layers and the decreased electric field intensity （EFI）. In addition, the Nb2O5 HR coating achieves the highest LIDT at 25.6 J/cm^2 in both single layers and HR coatings.
文摘HfO2 and SiO2 single layer is deposited on glass substrate with plasma ion assistance provided by Leybold advanced plasma source （APS）. The deposition is performed with a bias voltage in the range of 70-130 V for HfO2, and 70-170 V for SiO2. Optical, structural, mechanical properties, as well as absorption and laser induced damage threshold at 1064 nm of HfO2 and SiO2 single layer deposited with the plasma ion assistance are systematically investigated. With the increase of APS bias voltage, coatings with higher refractive index, reduced surface roughness, and higher laser-induced damage threshold （LIDT） are obtained, and no significant change of the absorption at 1064 nm is observed. For HfO2, a bias voltage can be identified to achieve coatings without any stress. However, too-high bias voltage can cause the increase of surface roughness and stress, and decrease the LIDT. The bias voltage can be properly identified to achieve coatings with desired properties.
