A new type of 785 nm semiconductor laser device has been proposed.The thin cladding and mode expansion layer structure incorporated into the epitaxy on the p-side significantly impacts the regulation of grating etchin...A new type of 785 nm semiconductor laser device has been proposed.The thin cladding and mode expansion layer structure incorporated into the epitaxy on the p-side significantly impacts the regulation of grating etching depth.Thinning of the p-side waveguide layer makes the light field bias to the n-side cladding layer.By coordinating the confinement effect of the cladding layer,the light confinement factor on the p-side is regulated.On the other hand,the introduction of a mode expansion layer facilitates the expansion of the mode profile on the p side cladding layer.Both these factors contribute positively to reducing the grating etching depth.Compared to the reported epitaxial structures of symmetric waveguides,the new structure significantly reduces the etching depth of the grating while ensuring adequate reflection intensity and maintaining resonance.Moreover,to improve the output performance of the device,the new epitaxial structure has been optimized.Based on the traditional epitaxial structure,an energy release layer and an electron blocking layer are added to improve the electronic recombination efficiency.This improved structure has an output performance comparable to that of a symmetric waveguide,despite being able to have a smaller gain area.展开更多
Germanium(Ge)-air battery,a new type of semiconductor-air battery,has garnered increasing attention owing to its environmental friendliness,safety,and excellent dynamic performance.However,the flat Ge anode is prone t...Germanium(Ge)-air battery,a new type of semiconductor-air battery,has garnered increasing attention owing to its environmental friendliness,safety,and excellent dynamic performance.However,the flat Ge anode is prone to passivation,owing to GeO_(2) accumulation on its surface,resulting in premature discharge termination.In this study,various nano-Ge pyramid structures(GePS)were prepared using chemical etching(CE)and metal-assisted chemical etching(MACE)methods to enhance the specific surface area of the Ge anode,thereby facilitating the dissolution of the passivation layer.This study revealed that the MACE method significantly accelerated the etching rate of the Ge surface,producing exceptional GePS.Furthermore,Ge-air batteries employing Ge anodes prepared using MACE demonstrated an exceptional discharge life of up to 9240 h(385 days).The peak power density reached 3.03mW/cm^(2),representing improvements of more than 2 times and 1.8 times,respectively,compared with batteries using flat Ge anodes.This study presents a straightforward approach to enhance Ge anode performance,thereby expanding the potential applications of Ge-air batteries.展开更多
A micro direct methanol fuel cell （μDMFC） using MEMS technology is reported. The prototype features a unique 3D air-breathing cathode structure fabricated using KOH etching and double-side lithography. The optimiza...A micro direct methanol fuel cell （μDMFC） using MEMS technology is reported. The prototype features a unique 3D air-breathing cathode structure fabricated using KOH etching and double-side lithography. The optimization of the MEMS fabrication process is analyzed. The experimental results show the prototype generates a maximum power density of 2.52mW/cm^2 at room temperature. This performance is better than the published resuits of other silicon-based passive μDMFCs. Moreover,it is comparable with that of our previous active μDMFCs which require an external pump, certificating the feasibility of this new configuration.展开更多
A low hole injection efficiency for InGaN/GaN micro-light-emitting diodes(μLEDs) has become one of the main bottlenecks affecting the improvement of the external quantum efficiency(EQE) and the optical power. In this...A low hole injection efficiency for InGaN/GaN micro-light-emitting diodes(μLEDs) has become one of the main bottlenecks affecting the improvement of the external quantum efficiency(EQE) and the optical power. In this work, we propose and fabricate a polarization mismatched p-GaN/p-Al_(0.25)Ga_(0.75)N/p-GaN structure for 445 nm GaN-based μLEDs with the size of 40 × 40 μm^(2), which serves as the hole injection layer. The polarization-induced electric field in the p-GaN/p-Al_(0.25)Ga_(0.75)N/p-GaN structure provides holes with more energy and can facilitate the non-equilibrium holes to transport into the active region for radiative recombination. Meanwhile, a secondary etched mesa for μLEDs is also designed, which can effectively keep the holes apart from the defected region of the mesa sidewalls, and the surface nonradiative recombination can be suppressed. Therefore, the proposed μLED with the secondary etched mesa and the p-GaN/p-Al_(0.25)Ga_(0.75)N/p-GaN structure has the enhanced EQE and the improved optical power density when compared with the μLED without such designs.展开更多
Introduction of titanium oxides with high permittivity on etched aluminum foils’ surface has been successfully utilized to increase specific capacitance of anode foils for aluminum electrolytic capacitors. In order t...Introduction of titanium oxides with high permittivity on etched aluminum foils’ surface has been successfully utilized to increase specific capacitance of anode foils for aluminum electrolytic capacitors. In order to quantify the concentration of titanium (IV) on the etched aluminum foil precisely, a simple and rapid spectrophotometric procedure has been developed. After optimizing a series of variables including absorbance wavelength, concentration of nitric acid, concentration of hydrogen peroxide, nitration time and developing time, analytical precision and accuracy were tested by using standard working solution containing known amount of titanium (IV). The results showed that Lambert-Beer’s law was obeyed in the range of 0.01 to 3.00 mmol·L﹣1. The relative standard deviation (RSD) ranged from 0.67% to 1.09% (n = 6), and the recovery was between 99.17% - 100.03%. Investigation on effect of Al3+ ion indicated that there was no interference in the absorbance of titanium (IV) at 410 nm. The proposed procedure was applied to real samples for the determination of titanium (IV), and the results were in a good agreement with the values certified by inductively coupled plasma-atomic emission spectrometry (ICP-AES).展开更多
Due to the increasing applications in optical devices electronics and nanosensors[1], 1D nanomaterials are becoming the extensive research area of physics, chemistry, medical, electronics and biology. As a member of 1...Due to the increasing applications in optical devices electronics and nanosensors[1], 1D nanomaterials are becoming the extensive research area of physics, chemistry, medical, electronics and biology. As a member of 1D nanostructured materials, the multilayer nanowires exhibit special properties and have strong potential applications in the fields of optoelectronic devices and nanosensors [2].展开更多
Discrimination of dislocations is critical to the statistics of dislocation densities in 4H silicon carbide(4H-SiC),which are routinely used to evaluate the quality of 4H-SiC single crystals and homoepitaxial layers.I...Discrimination of dislocations is critical to the statistics of dislocation densities in 4H silicon carbide(4H-SiC),which are routinely used to evaluate the quality of 4H-SiC single crystals and homoepitaxial layers.In this work,we show that the inclination angles of the etch pits of molten-alkali etched 4H-SiC can be adopted to discriminate threading screw dislocations(TSDs),threading edge dislocations(TEDs)and basal plane dislocations(BPDs)in 4H-SiC.In n-type 4H-SiC,the inclination angles of the etch pits of TSDs,TEDs and BPDs in molten-alkali etched 4H-SiC are in the ranges of 27°−35°,8°−15°and 2°−4°,respectively.In semi-insulating 4H-SiC,the inclination angles of the etch pits of TSDs and TEDs are in the ranges of 31°−34°and 21°−24°,respectively.The inclination angles of dislocation-related etch pits are independent of the etching duration,which facilitates the discrimination and statistic of dislocations in 4H-SiC.More significantly,the inclination angle of a threading mixed dislocations(TMDs)is found to consist of characteristic angles of both TEDs and TSDs.This enables to distinguish TMDs from TSDs in 4H-SiC.展开更多
After electrolytically etched pattern graining surface of aluminum alloy, it is shows that there are porous oxide film containing α Al 2O 3 and α Al 2O 3 by means of SEM XRD and XPS analysis. In the ditches, a...After electrolytically etched pattern graining surface of aluminum alloy, it is shows that there are porous oxide film containing α Al 2O 3 and α Al 2O 3 by means of SEM XRD and XPS analysis. In the ditches, anodic oxidation makes pore density and diameter larger than other areas, and causes more coloring metal depositing and mutual cross linking. The electrolytically etched pattern surface shows relative deeper color on the ditches and lighter color on other areas, so it can be used for decoration. Electrolytic coloring metal exists in forms of Ag colloid and Ag 2O. Both anodic oxidation and electrolytic coloring affect the surface microstructure of aluminum alloy.展开更多
A new method is presented to tune Bragg wavelength slightly by using hydrofluoric acid to etch fiber cladding.The spectral characteristics before and after etching and the change properties of Bragg wavelength are stu...A new method is presented to tune Bragg wavelength slightly by using hydrofluoric acid to etch fiber cladding.The spectral characteristics before and after etching and the change properties of Bragg wavelength are studied.Cladding modes are reduced during the etching process.High-order cladding modes are converted into radiation modes,and energy of cladding modes is coupled to the outside.As the cladding radius decreases,the Bragg wavelength shifts to longer direction.Experimental results show that this method can tune Bragg wavelength slightly,and the tunable range is 0.002-0.120 nm.展开更多
An increasing {110} orientation degree behavior was observed during etching of chemical vapor deposition （CVD） diamond films by partially melting Ce-7%Fe alloys. In order to accurately investigate this phenomenon, t...An increasing {110} orientation degree behavior was observed during etching of chemical vapor deposition （CVD） diamond films by partially melting Ce-7%Fe alloys. In order to accurately investigate this phenomenon, the X-ray diffraction method was used to identify the changes in the surface crystal orientation of the diamond films etched by Ce-7%Fe alloys, and evolution of orientation along the growth direction of the un-etched diamond film was analyzed by electron backscattering diffraction （EBSD）, and then the morphology of etched diamond surface was observed by scanning electron microscopy （SEM）. The results showed that the {110 } orientation degree of diamond surface increased due to the anisotropy in diamond etching with Ce-7%Fe, which was verified by the etching ＂pit＂ in SEM micrographs.展开更多
The comparison of domestic and foreign studies has been utilized to extensively employ junction termination extension(JTE)structures for power devices.However,achieving a gradual doping concentration change in the lat...The comparison of domestic and foreign studies has been utilized to extensively employ junction termination extension(JTE)structures for power devices.However,achieving a gradual doping concentration change in the lateral direction is difficult for SiC devices since the diffusion constants of the implanted aluminum ions in SiC are much less than silicon.Many previously reported studies adopted many new structures to solve this problem.Additionally,the JTE structure is strongly sensitive to the ion implantation dose.Thus,GA-JTE,double-zone etched JTE structures,and SM-JTE with modulation spacing were reported to overcome the above shortcomings of the JTE structure and effectively increase the breakdown voltage.They provided a theoretical basis for fabricating terminal structures of 4H-SiC PiN diodes.This paper summarized the effects of different terminal structures on the electrical properties of SiC devices at home and abroad.Presently,the continuous development and breakthrough of terminal technology have significantly improved the breakdown voltage and terminal efficiency of 4H-SiC PiN power diodes.展开更多
Photoresist grating was fabricated by holography, and it was used in the mask of ion etching. The groovy depth of the etched glass grating was 1.6μm. The glass waveguide was formed by K^+/Na^+ ion exchanging. The las...Photoresist grating was fabricated by holography, and it was used in the mask of ion etching. The groovy depth of the etched glass grating was 1.6μm. The glass waveguide was formed by K^+/Na^+ ion exchanging. The laser beam of 633nm was coupled in the waveguide by a prism at one end, then, it passed through the grating and came out of the waveguide at other end. In the experiment, the Bragg diffraction with several orders was observed. The first order Bragg diffraction had the highest efficiency of 90 percent.展开更多
Nanopores and nanochannels produced by etching heavy ion tracks are widely used in contemporary science and technology[1]. Conical and doubly-conical nanopores (channels) have attracted special interest in the past de...Nanopores and nanochannels produced by etching heavy ion tracks are widely used in contemporary science and technology[1]. Conical and doubly-conical nanopores (channels) have attracted special interest in the past decade due to their potential in modern and rapidly growing fields, including molecular sensors, logic gates, nanoactuators, and other nanofluidic devices[2;3].展开更多
Semiconductor nuclear radiation detectors made from tertiary and quaternary compounds of cadmium telluride (CdTe) can operate at room temperature without cryogenic cooling. One of such materials that have become of gr...Semiconductor nuclear radiation detectors made from tertiary and quaternary compounds of cadmium telluride (CdTe) can operate at room temperature without cryogenic cooling. One of such materials that have become of great interest is cadmium zinc telluride selenide (CdZnTeSe). Compared to other CdTe-based materials, such as cadmium zinc telluride (CdZnTe), CdZnTeSe can be grown with much less Te inclusions and sub-grain boundary networks. Chemical etching is often used to smoothen wafer surfaces during detector fabrication. This paper presents the characterization of CdZnTeSe that is chemically etched using bromine methanol solution. Infrared imaging shows that the wafer has no sub-grain boundary networks that often limit detector performance. The current-voltage (I-V) characterization experiment gave a resistivity of 4.6 × 10<sup>10</sup> Ω-cm for the sample. The I-V curve was linear in the ±10 to ±50 volts range. An energy resolution of 7.2% was recorded at 100 V for the 59.6-keV gamma line of <sup>241</sup>Am.展开更多
Deeply etched rib waveguides on silicon on insulator platform were not addressed well in research publications. We have analyzed single mode condition and polarization independence of a deeply etched rib waveguide （D...Deeply etched rib waveguides on silicon on insulator platform were not addressed well in research publications. We have analyzed single mode condition and polarization independence of a deeply etched rib waveguide （DE-RW） structure from biosensing perspective. With this rib structure, an asymmetrically etched integrated optic directional coupler has been numerically modeled to have the same coupling length for quasi- TE and TM modes. The coupling coefficients with the glucose solution as an upper cladding were calculated using a full vector mode solver, and the bulk refractive index sensitivity of the sensor was found as 28.305 × 10^-2/RIU for a fundamental quasi-TE mode.展开更多
By applying the specific properties and the fabricating technology of the deep etched elements presented by us, the even device of deep etched binary optics has been designed and fabricated which can be used in quasi-...By applying the specific properties and the fabricating technology of the deep etched elements presented by us, the even device of deep etched binary optics has been designed and fabricated which can be used in quasi-molecule laser exposure system. This even device is light in weight, easy to adjust and has a high utilization rate of energy and is able to project well-distributed light beams. So it is better than the conventional one which was an array made up of quartz sticks. The properties and designed parameters were studied and simulated. The fabricated even was precisely tested by high precision Alpha-Steper. The testing result of the surface relief structures of the even has been profoundly analyzed by introducing “boundary errors”. The theory agrees well with the results of the experiment. This is the first successful application of the deep etched theory and technology of binary optics to the exposure system of microfabrication.展开更多
Using a center etched single mode optical fiber, a simple vibration senor is designed to monitor the vibrations of a simply supported beam. The sensor has high linear response to the axial displacement of about 0.8mm ...Using a center etched single mode optical fiber, a simple vibration senor is designed to monitor the vibrations of a simply supported beam. The sensor has high linear response to the axial displacement of about 0.8mm with a sensitivity of 32mV/10p, m strain. The sensor is tested for periodic and suddenly released forces, and the results are found to coincide with the theoretical values. This simple design, small in size and low cost sensor may find applications in industry and civil engineering to monitor the vibrations of the beam structures and bridges.展开更多
A flat-topped etched diffraction grating (EDG) demultiplexer with a low polarization-dependent loss (PDL) is designed. A design and simulation method based on the method of moment (MoM) is proposed. A 65-channcl EDG d...A flat-topped etched diffraction grating (EDG) demultiplexer with a low polarization-dependent loss (PDL) is designed. A design and simulation method based on the method of moment (MoM) is proposed. A 65-channcl EDG demultiplexer with channel spacing of 100 GHz is considered as a design example. A tapered multi-mode interferometer (MMI) is used to flatten the passband of the EDG demultiplexer. The numerical results show that the exit width of the tapered waveguide impacts the loss of the TE case more than that of the TM case. Based on this fact, the exit width of the taper is optimized to obtain the lowest PDL. The tapering angle is also optimized where the minimal ripple is obtained. The designed EDG demultiplexer has an excellent flat-topped spectral response and a very low PDL.展开更多
This paper presents the design and fabrication of an etched implant junction termination extension（JTE）for high-voltage 4H-SiC PiN diodes. Unlike the conventional JTE structure, the proposed structure utilizes multi...This paper presents the design and fabrication of an etched implant junction termination extension（JTE）for high-voltage 4H-SiC PiN diodes. Unlike the conventional JTE structure, the proposed structure utilizes multiple etching steps to achieve the optimum JTE concentration range. The simulation results show that the etched implant JTE method can improve the blocking voltage of SiC PiN diodes and also provides broad process latitude for parameter variations, such as implantation dose and activation annealing condition. The fabricated SiC PiN diodes with the etched implant JTE exhibit a highest blocking voltage of 4.5 kV and the forward on-state voltage of 4.6 V at room temperature. These results are of interest for understanding the etched implant method in the fabrication of high-voltage power devices.展开更多
文摘A new type of 785 nm semiconductor laser device has been proposed.The thin cladding and mode expansion layer structure incorporated into the epitaxy on the p-side significantly impacts the regulation of grating etching depth.Thinning of the p-side waveguide layer makes the light field bias to the n-side cladding layer.By coordinating the confinement effect of the cladding layer,the light confinement factor on the p-side is regulated.On the other hand,the introduction of a mode expansion layer facilitates the expansion of the mode profile on the p side cladding layer.Both these factors contribute positively to reducing the grating etching depth.Compared to the reported epitaxial structures of symmetric waveguides,the new structure significantly reduces the etching depth of the grating while ensuring adequate reflection intensity and maintaining resonance.Moreover,to improve the output performance of the device,the new epitaxial structure has been optimized.Based on the traditional epitaxial structure,an energy release layer and an electron blocking layer are added to improve the electronic recombination efficiency.This improved structure has an output performance comparable to that of a symmetric waveguide,despite being able to have a smaller gain area.
基金financially supported by the National Natural Science Foundation of China(No.61904073)Spring City Plan-Special Program for Young Talents(No.K202005007)+2 种基金Yunnan Talents Support Plan for Yong Talents(No.XDYC-QNRC-2022-0482)Yunnan Local Colleges Applied Basic Research Projects(No.202101BA070001-138)Frontier Research Team of Kunming University 2023.
文摘Germanium(Ge)-air battery,a new type of semiconductor-air battery,has garnered increasing attention owing to its environmental friendliness,safety,and excellent dynamic performance.However,the flat Ge anode is prone to passivation,owing to GeO_(2) accumulation on its surface,resulting in premature discharge termination.In this study,various nano-Ge pyramid structures(GePS)were prepared using chemical etching(CE)and metal-assisted chemical etching(MACE)methods to enhance the specific surface area of the Ge anode,thereby facilitating the dissolution of the passivation layer.This study revealed that the MACE method significantly accelerated the etching rate of the Ge surface,producing exceptional GePS.Furthermore,Ge-air batteries employing Ge anodes prepared using MACE demonstrated an exceptional discharge life of up to 9240 h(385 days).The peak power density reached 3.03mW/cm^(2),representing improvements of more than 2 times and 1.8 times,respectively,compared with batteries using flat Ge anodes.This study presents a straightforward approach to enhance Ge anode performance,thereby expanding the potential applications of Ge-air batteries.
文摘A micro direct methanol fuel cell （μDMFC） using MEMS technology is reported. The prototype features a unique 3D air-breathing cathode structure fabricated using KOH etching and double-side lithography. The optimization of the MEMS fabrication process is analyzed. The experimental results show the prototype generates a maximum power density of 2.52mW/cm^2 at room temperature. This performance is better than the published resuits of other silicon-based passive μDMFCs. Moreover,it is comparable with that of our previous active μDMFCs which require an external pump, certificating the feasibility of this new configuration.
基金supported in part by the National Natural Science Foundation of China (Grant Nos.62074050 and 61975051)Research Fund by State Key Laboratory of Reliability and Intelligence of Electrical Equipment,Hebei University of Technology (Grant Nos.EERI PI2020008 and EERI_PD2021012)Joint Research Project for Tunghsu Group and Hebei University of Technology (Grant No.HI1909)。
文摘A low hole injection efficiency for InGaN/GaN micro-light-emitting diodes(μLEDs) has become one of the main bottlenecks affecting the improvement of the external quantum efficiency(EQE) and the optical power. In this work, we propose and fabricate a polarization mismatched p-GaN/p-Al_(0.25)Ga_(0.75)N/p-GaN structure for 445 nm GaN-based μLEDs with the size of 40 × 40 μm^(2), which serves as the hole injection layer. The polarization-induced electric field in the p-GaN/p-Al_(0.25)Ga_(0.75)N/p-GaN structure provides holes with more energy and can facilitate the non-equilibrium holes to transport into the active region for radiative recombination. Meanwhile, a secondary etched mesa for μLEDs is also designed, which can effectively keep the holes apart from the defected region of the mesa sidewalls, and the surface nonradiative recombination can be suppressed. Therefore, the proposed μLED with the secondary etched mesa and the p-GaN/p-Al_(0.25)Ga_(0.75)N/p-GaN structure has the enhanced EQE and the improved optical power density when compared with the μLED without such designs.
文摘Introduction of titanium oxides with high permittivity on etched aluminum foils’ surface has been successfully utilized to increase specific capacitance of anode foils for aluminum electrolytic capacitors. In order to quantify the concentration of titanium (IV) on the etched aluminum foil precisely, a simple and rapid spectrophotometric procedure has been developed. After optimizing a series of variables including absorbance wavelength, concentration of nitric acid, concentration of hydrogen peroxide, nitration time and developing time, analytical precision and accuracy were tested by using standard working solution containing known amount of titanium (IV). The results showed that Lambert-Beer’s law was obeyed in the range of 0.01 to 3.00 mmol·L﹣1. The relative standard deviation (RSD) ranged from 0.67% to 1.09% (n = 6), and the recovery was between 99.17% - 100.03%. Investigation on effect of Al3+ ion indicated that there was no interference in the absorbance of titanium (IV) at 410 nm. The proposed procedure was applied to real samples for the determination of titanium (IV), and the results were in a good agreement with the values certified by inductively coupled plasma-atomic emission spectrometry (ICP-AES).
文摘Due to the increasing applications in optical devices electronics and nanosensors[1], 1D nanomaterials are becoming the extensive research area of physics, chemistry, medical, electronics and biology. As a member of 1D nanostructured materials, the multilayer nanowires exhibit special properties and have strong potential applications in the fields of optoelectronic devices and nanosensors [2].
基金supported by“Pioneer”and“Leading Goose”R&D Program of Zhejiang(Grant No.2022C01021)National Key Research and Development Program of China(Grant Nos.2018YFB2200101)+3 种基金Natural Science Foundation of China(Grant Nos.61774133)Fundamental Research Funds for the Central Universities(Grant No.2018XZZX003-02)Natural Science Foundation of China for Innovative Research Groups(Grant No.61721005)Zhejiang University Education Foundation Global Partnership Fund.
文摘Discrimination of dislocations is critical to the statistics of dislocation densities in 4H silicon carbide(4H-SiC),which are routinely used to evaluate the quality of 4H-SiC single crystals and homoepitaxial layers.In this work,we show that the inclination angles of the etch pits of molten-alkali etched 4H-SiC can be adopted to discriminate threading screw dislocations(TSDs),threading edge dislocations(TEDs)and basal plane dislocations(BPDs)in 4H-SiC.In n-type 4H-SiC,the inclination angles of the etch pits of TSDs,TEDs and BPDs in molten-alkali etched 4H-SiC are in the ranges of 27°−35°,8°−15°and 2°−4°,respectively.In semi-insulating 4H-SiC,the inclination angles of the etch pits of TSDs and TEDs are in the ranges of 31°−34°and 21°−24°,respectively.The inclination angles of dislocation-related etch pits are independent of the etching duration,which facilitates the discrimination and statistic of dislocations in 4H-SiC.More significantly,the inclination angle of a threading mixed dislocations(TMDs)is found to consist of characteristic angles of both TEDs and TSDs.This enables to distinguish TMDs from TSDs in 4H-SiC.
文摘After electrolytically etched pattern graining surface of aluminum alloy, it is shows that there are porous oxide film containing α Al 2O 3 and α Al 2O 3 by means of SEM XRD and XPS analysis. In the ditches, anodic oxidation makes pore density and diameter larger than other areas, and causes more coloring metal depositing and mutual cross linking. The electrolytically etched pattern surface shows relative deeper color on the ditches and lighter color on other areas, so it can be used for decoration. Electrolytic coloring metal exists in forms of Ag colloid and Ag 2O. Both anodic oxidation and electrolytic coloring affect the surface microstructure of aluminum alloy.
基金supported by the National Natural Science Foundation of China (Nos.60837002 and 61177069)the Ph.D. Programs Foundation of Ministry of Education of China (No.20090009110003)the Fundamental Research Funds for the Central Universities (No.2011YJS219)
文摘A new method is presented to tune Bragg wavelength slightly by using hydrofluoric acid to etch fiber cladding.The spectral characteristics before and after etching and the change properties of Bragg wavelength are studied.Cladding modes are reduced during the etching process.High-order cladding modes are converted into radiation modes,and energy of cladding modes is coupled to the outside.As the cladding radius decreases,the Bragg wavelength shifts to longer direction.Experimental results show that this method can tune Bragg wavelength slightly,and the tunable range is 0.002-0.120 nm.
基金Project supported by the Fundamental Research Fund for the Central Universities (YWF-10-B01)
文摘An increasing {110} orientation degree behavior was observed during etching of chemical vapor deposition （CVD） diamond films by partially melting Ce-7%Fe alloys. In order to accurately investigate this phenomenon, the X-ray diffraction method was used to identify the changes in the surface crystal orientation of the diamond films etched by Ce-7%Fe alloys, and evolution of orientation along the growth direction of the un-etched diamond film was analyzed by electron backscattering diffraction （EBSD）, and then the morphology of etched diamond surface was observed by scanning electron microscopy （SEM）. The results showed that the {110 } orientation degree of diamond surface increased due to the anisotropy in diamond etching with Ce-7%Fe, which was verified by the etching ＂pit＂ in SEM micrographs.
基金financially supported by the Scientific and Technology Project of State Grid Corporation of China,Research on Dry Etching Forming Technology of Silicon Carbide Device,Project No.5500-202158437A-0-0-00.
文摘The comparison of domestic and foreign studies has been utilized to extensively employ junction termination extension(JTE)structures for power devices.However,achieving a gradual doping concentration change in the lateral direction is difficult for SiC devices since the diffusion constants of the implanted aluminum ions in SiC are much less than silicon.Many previously reported studies adopted many new structures to solve this problem.Additionally,the JTE structure is strongly sensitive to the ion implantation dose.Thus,GA-JTE,double-zone etched JTE structures,and SM-JTE with modulation spacing were reported to overcome the above shortcomings of the JTE structure and effectively increase the breakdown voltage.They provided a theoretical basis for fabricating terminal structures of 4H-SiC PiN diodes.This paper summarized the effects of different terminal structures on the electrical properties of SiC devices at home and abroad.Presently,the continuous development and breakthrough of terminal technology have significantly improved the breakdown voltage and terminal efficiency of 4H-SiC PiN power diodes.
基金Academia Sinica and the Ministry of Posts and Telecommunications
文摘Photoresist grating was fabricated by holography, and it was used in the mask of ion etching. The groovy depth of the etched glass grating was 1.6μm. The glass waveguide was formed by K^+/Na^+ ion exchanging. The laser beam of 633nm was coupled in the waveguide by a prism at one end, then, it passed through the grating and came out of the waveguide at other end. In the experiment, the Bragg diffraction with several orders was observed. The first order Bragg diffraction had the highest efficiency of 90 percent.
文摘Nanopores and nanochannels produced by etching heavy ion tracks are widely used in contemporary science and technology[1]. Conical and doubly-conical nanopores (channels) have attracted special interest in the past decade due to their potential in modern and rapidly growing fields, including molecular sensors, logic gates, nanoactuators, and other nanofluidic devices[2;3].
文摘Semiconductor nuclear radiation detectors made from tertiary and quaternary compounds of cadmium telluride (CdTe) can operate at room temperature without cryogenic cooling. One of such materials that have become of great interest is cadmium zinc telluride selenide (CdZnTeSe). Compared to other CdTe-based materials, such as cadmium zinc telluride (CdZnTe), CdZnTeSe can be grown with much less Te inclusions and sub-grain boundary networks. Chemical etching is often used to smoothen wafer surfaces during detector fabrication. This paper presents the characterization of CdZnTeSe that is chemically etched using bromine methanol solution. Infrared imaging shows that the wafer has no sub-grain boundary networks that often limit detector performance. The current-voltage (I-V) characterization experiment gave a resistivity of 4.6 × 10<sup>10</sup> Ω-cm for the sample. The I-V curve was linear in the ±10 to ±50 volts range. An energy resolution of 7.2% was recorded at 100 V for the 59.6-keV gamma line of <sup>241</sup>Am.
文摘Deeply etched rib waveguides on silicon on insulator platform were not addressed well in research publications. We have analyzed single mode condition and polarization independence of a deeply etched rib waveguide （DE-RW） structure from biosensing perspective. With this rib structure, an asymmetrically etched integrated optic directional coupler has been numerically modeled to have the same coupling length for quasi- TE and TM modes. The coupling coefficients with the glucose solution as an upper cladding were calculated using a full vector mode solver, and the bulk refractive index sensitivity of the sensor was found as 28.305 × 10^-2/RIU for a fundamental quasi-TE mode.
基金This work was supported by the National Natural Science Founation of China the Science and Technology Fund of Shenzhen.
文摘By applying the specific properties and the fabricating technology of the deep etched elements presented by us, the even device of deep etched binary optics has been designed and fabricated which can be used in quasi-molecule laser exposure system. This even device is light in weight, easy to adjust and has a high utilization rate of energy and is able to project well-distributed light beams. So it is better than the conventional one which was an array made up of quartz sticks. The properties and designed parameters were studied and simulated. The fabricated even was precisely tested by high precision Alpha-Steper. The testing result of the surface relief structures of the even has been profoundly analyzed by introducing “boundary errors”. The theory agrees well with the results of the experiment. This is the first successful application of the deep etched theory and technology of binary optics to the exposure system of microfabrication.
文摘Using a center etched single mode optical fiber, a simple vibration senor is designed to monitor the vibrations of a simply supported beam. The sensor has high linear response to the axial displacement of about 0.8mm with a sensitivity of 32mV/10p, m strain. The sensor is tested for periodic and suddenly released forces, and the results are found to coincide with the theoretical values. This simple design, small in size and low cost sensor may find applications in industry and civil engineering to monitor the vibrations of the beam structures and bridges.
基金This work was supported by the National Nat- ural Science Foundation of China under Grant No. 90101024 and 60377022.
文摘A flat-topped etched diffraction grating (EDG) demultiplexer with a low polarization-dependent loss (PDL) is designed. A design and simulation method based on the method of moment (MoM) is proposed. A 65-channcl EDG demultiplexer with channel spacing of 100 GHz is considered as a design example. A tapered multi-mode interferometer (MMI) is used to flatten the passband of the EDG demultiplexer. The numerical results show that the exit width of the tapered waveguide impacts the loss of the TE case more than that of the TM case. Based on this fact, the exit width of the taper is optimized to obtain the lowest PDL. The tapering angle is also optimized where the minimal ripple is obtained. The designed EDG demultiplexer has an excellent flat-topped spectral response and a very low PDL.
基金Project supported by the Science and Technology Development Foundation of China Academy of Engineering Physics(No.2014A05011)the Special Foundation of President of China Academy of Engineering Physics(No.2014-1-100)
文摘This paper presents the design and fabrication of an etched implant junction termination extension（JTE）for high-voltage 4H-SiC PiN diodes. Unlike the conventional JTE structure, the proposed structure utilizes multiple etching steps to achieve the optimum JTE concentration range. The simulation results show that the etched implant JTE method can improve the blocking voltage of SiC PiN diodes and also provides broad process latitude for parameter variations, such as implantation dose and activation annealing condition. The fabricated SiC PiN diodes with the etched implant JTE exhibit a highest blocking voltage of 4.5 kV and the forward on-state voltage of 4.6 V at room temperature. These results are of interest for understanding the etched implant method in the fabrication of high-voltage power devices.
