The performance of optical interconnection has improved dramatically in recent years.Silicon-based optoelectronic heterogeneous integration is the key enabler to achieve high performance optical interconnection,which ...The performance of optical interconnection has improved dramatically in recent years.Silicon-based optoelectronic heterogeneous integration is the key enabler to achieve high performance optical interconnection,which not only provides the optical gain which is absent from native Si substrates and enables complete photonic functionalities on chip,but also improves the system performance through advanced heterogeneous integrated packaging.This paper reviews recent progress of silicon-based optoelectronic heterogeneous integration in high performance optical interconnection.The research status,development trend and application of ultra-low loss optical waveguides,high-speed detectors,high-speed modulators,lasers and 2D,2.5D,3D and monolithic integration are focused on.展开更多
Silicon-based materials have demonstrated remarkable potential in high-energy-density batteries owing to their high theoretical capacity.However,the significant volume expansion of silicon seriously hinders its utiliz...Silicon-based materials have demonstrated remarkable potential in high-energy-density batteries owing to their high theoretical capacity.However,the significant volume expansion of silicon seriously hinders its utilization as a lithium-ion anode.Herein,a functionalized high-toughness polyimide(PDMI) is synthesized by copolymerizing the 4,4'-Oxydiphthalic anhydride(ODPA) with 4,4'-oxydianiline(ODA),2,3-diaminobenzoic acid(DABA),and 1,3-bis(3-aminopropyl)-tetramethyl disiloxane(DMS).The combination of rigid benzene rings and flexible oxygen groups(-O-) in the PDMI molecular chain via a rigidness/softness coupling mechanism contributes to high toughness.The plentiful polar carboxyl(-COOH) groups establish robust bonding strength.Rapid ionic transport is achieved by incorporating the flexible siloxane segment(Si-O-Si),which imparts high molecular chain motility and augments free volume holes to facilitate lithium-ion transport(9.8 × 10^(-10) cm^(2) s^(-1) vs.16 × 10^(-10) cm^(2) s~(-1)).As expected,the SiO_x@PDMI-1.5 electrode delivers brilliant long-term cycle performance with a remarkable capacity retention of 85% over 500 cycles at 1.3 A g^(-1).The well-designed functionalized polyimide also significantly enhances the electrochemical properties of Si nanoparticles electrode.Meanwhile,the assembled SiO_x@PDMI-1.5/NCM811 full cell delivers a high retention of 80% after 100 cycles.The perspective of the binder design strategy based on polyimide modification delivers a novel path toward high-capacity electrodes for high-energy-density batteries.展开更多
The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/M...The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.展开更多
The solvation structure of Li^(+) in chemical prelithiation reagent plays a key role in improving the low initial Coulombic efficiency(ICE) and poor cycle performance of silicon-based materials. Never theless, the che...The solvation structure of Li^(+) in chemical prelithiation reagent plays a key role in improving the low initial Coulombic efficiency(ICE) and poor cycle performance of silicon-based materials. Never theless, the chemical prelithiation agent is difficult to dope active Li^(+) in silicon-based anodes because of their low working voltage and sluggish Li^(+) diffusion rate. By selecting the lithium–arene complex reagent with 4-methylbiphenyl as an anion ligand and 2-methyltetrahydrofuran as a solvent, the as-prepared micro-sized Si O/C anode can achieve an ICE of nearly 100%. Interestingly, the best prelithium efficiency does not correspond to the lowest redox half-potential(E_(1/2)), and the prelithiation efficiency is determined by the specific influencing factors(E_(1/2), Li^(+) concentration, desolvation energy, and ion diffusion path). In addition, molecular dynamics simulations demonstrate that the ideal prelithiation efficiency can be achieved by choosing appropriate anion ligand and solvent to regulate the solvation structure of Li^(+). Furthermore, the positive effect of prelithiation on cycle performance has been verified by using an in-situ electrochemical dilatometry and solid electrolyte interphase film characterizations.展开更多
Three new catalysts based on the silica gel supported polyether ionic liquids(ILs), i.e., [HO-PECH-MIM]ClSi, [H2N-PECH-MIM]Cl-Si, and [HOOC-PECH-MIM]Cl-Si, were prepared, and their chemical structures were characteriz...Three new catalysts based on the silica gel supported polyether ionic liquids(ILs), i.e., [HO-PECH-MIM]ClSi, [H2N-PECH-MIM]Cl-Si, and [HOOC-PECH-MIM]Cl-Si, were prepared, and their chemical structures were characterized by infrared(IR) spectroscopy and nuclear magnetic resonance(NMR) spectroscopy. Thermogravimetric analyzer(TG), X-ray diffractometer(XRD) and scanning electron microscope(SEM) were used to evaluate their thermal stability,crystalline structure and apparent morphology, respectively. Surface areas of the prepared catalysts were calculated by the Brunauer-Emmett-Teller(BET) method. The catalytic reaction for the synthesis of propylene carbonate(PC) using CO_2 and propylene oxide(PO) in the presence of the prepared catalysts was studied. The influences of times of recycling and catalyst structure on catalytic performance were also investigated. The experimental results showed that the silica gel supported polyether ILs catalysts successfully prepared under mild condition could possess the advantages of high activity, excellent thermal stability, good selectivity and easy recycling, while the phase transition of the liquid polyether ILs catalysts was also achieved. When the reaction temperature was 90 °C, the CO_2 pressure was 2.0 MPa and the dosage of the catalyst was 2.5%, [HOOC-PECH-MIM]Cl-Si was found to have the best catalytic performance in the catalytic process, with the conversion rate reaching 100% and the selectivity equating to 98.2%. The conversion rate and selectivity still could reach more than 90% even after the catalyst was reused for 15 times.展开更多
A three-terminal silicon-based light emitting device is proposed and fabricated in standard 0.35 μm complementary metal-oxide-semiconductor technology. This device is capable of versatile working modes： it can emit ...A three-terminal silicon-based light emitting device is proposed and fabricated in standard 0.35 μm complementary metal-oxide-semiconductor technology. This device is capable of versatile working modes： it can emit visible to near infra-red （NIR） light （the spectrum ranges from 500 nm to 1000 nm） in reverse bias avalanche breakdown mode with working voltage between 8.35 V-12 V and emit NIR light （the spectrum ranges from 900 nm to 1300 nm） in the forward injection mode with working voltage below 2 V. An apparent modulation effect on the light intensity from the polysilicon gate is observed in the forward injection mode. Furthermore, when the gate oxide is broken down, NIR light is emitted from the polysilicon/oxide/silicon structure. Optoelectronic characteristics of the device working in different modes are measured and compared. The mechanisms behind these different emissions are explored.展开更多
The micro-mechanism of the silicon-based waveguide surface smoothing is investigated systematically to explore the effects of silicon-hydrogen bonds on high-temperature hydrogen annealing waveguides. The effect of sil...The micro-mechanism of the silicon-based waveguide surface smoothing is investigated systematically to explore the effects of silicon-hydrogen bonds on high-temperature hydrogen annealing waveguides. The effect of silicon- hydrogen bonds on the surface migration movement of silicon atoms and the waveguide surface topography are revealed. The micro-migration from an upper state to a lower state of silicon atoms is driven by silicon- hydrogen bonding, which is the key to ameliorate the rough surface morphology of the silicon-based waveguide. The process of hydrogen annealing is experimentally validated based on the simulated parameters. The surface roughness declines from 1.523nm to 0.461 nm.展开更多
This paper presents a brief overview of several promising design technologies for high efficiency silicon-based radio frequency （RF） power amplifiers （PAs） as well as the use of these technologies in mobile broadb...This paper presents a brief overview of several promising design technologies for high efficiency silicon-based radio frequency （RF） power amplifiers （PAs） as well as the use of these technologies in mobile broadband wireless communications. Four important aspects of PA design are addressed in this paper. First, we look at class-E PA design equations and provide an example of a class-E PA that achieves efficiency of 65-70% at 2.4 GHz. Then, we discuss state-of-the-art envelope tracking （ET） design for monolithic wideband RF mobile transmitter applications. A brief overview of Doherty PA design for the next-generation wireless handset applications is then given. Towards the end of the paper, we discuss an inherently broadband and highly efficient class-J PA design targeting future multi-band multi-standard wireless communication protocols.展开更多
The Br?nsted-acidic polyether ionic liquids(ILs)with different polymerization degrees(n value)were prepared via the reaction of tetramethylguanidine and epoxy ethane,followed by successive reactions with 1,3-propane s...The Br?nsted-acidic polyether ionic liquids(ILs)with different polymerization degrees(n value)were prepared via the reaction of tetramethylguanidine and epoxy ethane,followed by successive reactions with 1,3-propane sultone and trifluoromethanesulfonic acid(TfOH).The prepared ILs were characterized by infrared spectroscopy and 1H nuclear magnetic resonance spectroscopy,and their thermal stability was determined by thermal gravimetry.The synthesized polyether ILs coupled with TfOH were used to catalyze the alkylation reaction of isobutane and isobutene for the preparation of alkylate gasoline.The polyether ILs could improve the substrate dissolution and promote the separation of the catalyst from the products.The ideal IL(n=94)was determined.The optimized alkylation reaction conditions covered:a VTfOH/VIL ratio of 0.35,a reaction temperature of 40℃,a reaction time of 50 min,and a stirring speed of 800 r/min.The conversion of isobutene was 92.4%and the selectivity for the C8-product was 81.6%.Under optimal conditions,the catalyst life was determined and TfOH showed improved cyclic performance in the polyether ILs.After 8 operating cycles,the catalytic activity of the catalyst showed negligible decline.展开更多
The extinction ratio and insertion loss of spatial light modulator are subject to the material problem, thus limiting its applications. One reflection-type silicon-based spatial light modulator with high reflective ma...The extinction ratio and insertion loss of spatial light modulator are subject to the material problem, thus limiting its applications. One reflection-type silicon-based spatial light modulator with high reflective materials outside the Fabry-Perot cavity is demonstrated in this paper. The reflectivity values of the outside-cavity materials with different film layer numbers are simulated. The reflectivity values of 6-pair Ta2O5/SiO2 films at 1550 nm are experimentally verified to be as high as 99.9%. The surfaces of 6-pair Ta2O5/SiO2 films are smooth: their root-mean-square roughness values are as small as 0.53 nm. The insertion loss of the device at 1550 nm is only 1.2 dB. The high extinction ratio of the device at 1550 nm and 11 V is achieved to be 29.7 dB. The spatial light modulator has a high extinction ratio and low insertion loss for applications.展开更多
A near-infrared germanium(Ge)Schottky photodetector(PD)with an ultrathin silicon(Si)barrier enhancement layer between the indium-doped tin oxide(ITO)electrode and Ge epilayer on Si or silicon-on-insulator(SOI)is propo...A near-infrared germanium(Ge)Schottky photodetector(PD)with an ultrathin silicon(Si)barrier enhancement layer between the indium-doped tin oxide(ITO)electrode and Ge epilayer on Si or silicon-on-insulator(SOI)is proposed and fabricated.The well-behaved ITO/Si cap/Ge Schottky junctions without intentional doping process for the Ge epilayer are formed on the Si and SOI substrates.The Si-and SOI-based ITO/Si cap/Ge Schottky PDs exhibit low dark current densities of 33 mA/cm2 and 44 mA/cm2,respectively.Benefited from the high transmissivity of ITO electrode and the reflectivity of SOI substrate,an optical responsivity of 0.19 A/W at 1550 nm wavelength is obtained for the SOI-based ITO/Si cap/Ge Schottky PD.These complementary metal–oxide–semiconductor(CMOS)compatible Si(or SOI)-based ITO/Si cap/Ge Schottky PDs are quite useful for detecting near-infrared wavelengths with high efficiency.展开更多
In view of the existing design challenges for Terahertz(THz)power amplifiers(PAs),the common design methods and the efforts of the State Key Laboratory of Millimeter Wave,Southeast University,China in the development ...In view of the existing design challenges for Terahertz(THz)power amplifiers(PAs),the common design methods and the efforts of the State Key Laboratory of Millimeter Wave,Southeast University,China in the development of silicon-based THz PAs,mainly including silicon-based PAs with operating frequencies covering 100–300 GHz,are summarized in this paper.Particularly,we design an LC-balun-based two-stage differential cascode PA with a center frequency of 150 GHz and an output power of 14 dBm.Based on a Marchand balun,we report a 220 GHz three-stage differential cascode PA with a saturated output power of 9.5 dBm.To further increase the output power of THz PA,based on a four-way differential power combining technique,we report a 211–263 GHz dual-LC-tank-based broadband PA with a recorded 14.7 dBm Psat and 16.4 dB peak gain.All the above circuits are designed in a standard 130 nm silicon germanium(SiGe)BiCMOS process.展开更多
Radio frequency(RF)reflectometry is an effective and sensitive technique for detecting charge signal in semiconductor quantum dots,and its measurement bandwidth can reach the MHz level.However,in accumulation mode dev...Radio frequency(RF)reflectometry is an effective and sensitive technique for detecting charge signal in semiconductor quantum dots,and its measurement bandwidth can reach the MHz level.However,in accumulation mode devices,the presence of parasitic capacitance makes RF reflectometry more difficult.The universal approach is relocating the ion implantation region approximately 10μm from the center of the single-electron transistor(SET)and optimizing the design of the accumulation gates.But,this method puts forward more stringent requirements for micro-nano fabrication processing.Here,we propose a split-gate structure that enables RF reflectometry when the ion-implanted region and the ohmic contact are farther from the SET center.In Si-MOS devices,we employ a split-gate structure to achieve RF detection,with the ion-implanted region located 150μm away from the center of the SET.Within an integration time of 140 nanoseconds,we achieved a readout fidelity exceeding 99.8%and a detection bandwidth of over 2 MHz.This is an alternative solution for micro-nano fabrication processing that cannot achieve ion implantation areas closer to the center of the chip,and is applicable to various silicon-based semiconductor systems.展开更多
基金Project supported in part by the National Key Research and Development Program of China(Grant No.2021YFB2206504)the National Natural Science Foundation of China(Grant No.62235017)the China Postdoctoral Science Foundation(Grant No.2021M703125).
文摘The performance of optical interconnection has improved dramatically in recent years.Silicon-based optoelectronic heterogeneous integration is the key enabler to achieve high performance optical interconnection,which not only provides the optical gain which is absent from native Si substrates and enables complete photonic functionalities on chip,but also improves the system performance through advanced heterogeneous integrated packaging.This paper reviews recent progress of silicon-based optoelectronic heterogeneous integration in high performance optical interconnection.The research status,development trend and application of ultra-low loss optical waveguides,high-speed detectors,high-speed modulators,lasers and 2D,2.5D,3D and monolithic integration are focused on.
基金supported by the National Natural Science Foundation of China (51673017)the National Natural Science Foundation of China (21404005)+1 种基金the Fundamental Research Funds for the Central Universities (XK1802-2)the Natural Science Foundation of Jiangsu Province (BK20150273)。
文摘Silicon-based materials have demonstrated remarkable potential in high-energy-density batteries owing to their high theoretical capacity.However,the significant volume expansion of silicon seriously hinders its utilization as a lithium-ion anode.Herein,a functionalized high-toughness polyimide(PDMI) is synthesized by copolymerizing the 4,4'-Oxydiphthalic anhydride(ODPA) with 4,4'-oxydianiline(ODA),2,3-diaminobenzoic acid(DABA),and 1,3-bis(3-aminopropyl)-tetramethyl disiloxane(DMS).The combination of rigid benzene rings and flexible oxygen groups(-O-) in the PDMI molecular chain via a rigidness/softness coupling mechanism contributes to high toughness.The plentiful polar carboxyl(-COOH) groups establish robust bonding strength.Rapid ionic transport is achieved by incorporating the flexible siloxane segment(Si-O-Si),which imparts high molecular chain motility and augments free volume holes to facilitate lithium-ion transport(9.8 × 10^(-10) cm^(2) s^(-1) vs.16 × 10^(-10) cm^(2) s~(-1)).As expected,the SiO_x@PDMI-1.5 electrode delivers brilliant long-term cycle performance with a remarkable capacity retention of 85% over 500 cycles at 1.3 A g^(-1).The well-designed functionalized polyimide also significantly enhances the electrochemical properties of Si nanoparticles electrode.Meanwhile,the assembled SiO_x@PDMI-1.5/NCM811 full cell delivers a high retention of 80% after 100 cycles.The perspective of the binder design strategy based on polyimide modification delivers a novel path toward high-capacity electrodes for high-energy-density batteries.
文摘The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.
基金supported by the National Natural Science Foundation of China (21875107, U1802256, and 22209204)Leading Edge Technology of Jiangsu Province (BK20220009), the Natural Science Foundation of Jiangsu Province (BK20221140)+2 种基金the China Postdoctoral Science Foundation (2022M713364)Jiangsu Specially Appointed Professors ProgramPriority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)。
文摘The solvation structure of Li^(+) in chemical prelithiation reagent plays a key role in improving the low initial Coulombic efficiency(ICE) and poor cycle performance of silicon-based materials. Never theless, the chemical prelithiation agent is difficult to dope active Li^(+) in silicon-based anodes because of their low working voltage and sluggish Li^(+) diffusion rate. By selecting the lithium–arene complex reagent with 4-methylbiphenyl as an anion ligand and 2-methyltetrahydrofuran as a solvent, the as-prepared micro-sized Si O/C anode can achieve an ICE of nearly 100%. Interestingly, the best prelithium efficiency does not correspond to the lowest redox half-potential(E_(1/2)), and the prelithiation efficiency is determined by the specific influencing factors(E_(1/2), Li^(+) concentration, desolvation energy, and ion diffusion path). In addition, molecular dynamics simulations demonstrate that the ideal prelithiation efficiency can be achieved by choosing appropriate anion ligand and solvent to regulate the solvation structure of Li^(+). Furthermore, the positive effect of prelithiation on cycle performance has been verified by using an in-situ electrochemical dilatometry and solid electrolyte interphase film characterizations.
基金supported by the National Natural Science Foundation of China (NSFC 21706163)the Liaoning Province Department of Education Foundation (LQGD2017020)
文摘Three new catalysts based on the silica gel supported polyether ionic liquids(ILs), i.e., [HO-PECH-MIM]ClSi, [H2N-PECH-MIM]Cl-Si, and [HOOC-PECH-MIM]Cl-Si, were prepared, and their chemical structures were characterized by infrared(IR) spectroscopy and nuclear magnetic resonance(NMR) spectroscopy. Thermogravimetric analyzer(TG), X-ray diffractometer(XRD) and scanning electron microscope(SEM) were used to evaluate their thermal stability,crystalline structure and apparent morphology, respectively. Surface areas of the prepared catalysts were calculated by the Brunauer-Emmett-Teller(BET) method. The catalytic reaction for the synthesis of propylene carbonate(PC) using CO_2 and propylene oxide(PO) in the presence of the prepared catalysts was studied. The influences of times of recycling and catalyst structure on catalytic performance were also investigated. The experimental results showed that the silica gel supported polyether ILs catalysts successfully prepared under mild condition could possess the advantages of high activity, excellent thermal stability, good selectivity and easy recycling, while the phase transition of the liquid polyether ILs catalysts was also achieved. When the reaction temperature was 90 °C, the CO_2 pressure was 2.0 MPa and the dosage of the catalyst was 2.5%, [HOOC-PECH-MIM]Cl-Si was found to have the best catalytic performance in the catalytic process, with the conversion rate reaching 100% and the selectivity equating to 98.2%. The conversion rate and selectivity still could reach more than 90% even after the catalyst was reused for 15 times.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.60536030,61036002,60776024,60877035 and 61036009)National High Technology Research and Development Program of China(Grant Nos.2007AA04Z329 and 2007AA04Z254)
文摘A three-terminal silicon-based light emitting device is proposed and fabricated in standard 0.35 μm complementary metal-oxide-semiconductor technology. This device is capable of versatile working modes： it can emit visible to near infra-red （NIR） light （the spectrum ranges from 500 nm to 1000 nm） in reverse bias avalanche breakdown mode with working voltage between 8.35 V-12 V and emit NIR light （the spectrum ranges from 900 nm to 1300 nm） in the forward injection mode with working voltage below 2 V. An apparent modulation effect on the light intensity from the polysilicon gate is observed in the forward injection mode. Furthermore, when the gate oxide is broken down, NIR light is emitted from the polysilicon/oxide/silicon structure. Optoelectronic characteristics of the device working in different modes are measured and compared. The mechanisms behind these different emissions are explored.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51505324,91123036,61471255 and 61474079the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No 20131402110013the Foundation for Young Scholars of Shanxi Province under Grant No 2014021023-3
文摘The micro-mechanism of the silicon-based waveguide surface smoothing is investigated systematically to explore the effects of silicon-hydrogen bonds on high-temperature hydrogen annealing waveguides. The effect of silicon- hydrogen bonds on the surface migration movement of silicon atoms and the waveguide surface topography are revealed. The micro-migration from an upper state to a lower state of silicon atoms is driven by silicon- hydrogen bonding, which is the key to ameliorate the rough surface morphology of the silicon-based waveguide. The process of hydrogen annealing is experimentally validated based on the simulated parameters. The surface roughness declines from 1.523nm to 0.461 nm.
文摘This paper presents a brief overview of several promising design technologies for high efficiency silicon-based radio frequency （RF） power amplifiers （PAs） as well as the use of these technologies in mobile broadband wireless communications. Four important aspects of PA design are addressed in this paper. First, we look at class-E PA design equations and provide an example of a class-E PA that achieves efficiency of 65-70% at 2.4 GHz. Then, we discuss state-of-the-art envelope tracking （ET） design for monolithic wideband RF mobile transmitter applications. A brief overview of Doherty PA design for the next-generation wireless handset applications is then given. Towards the end of the paper, we discuss an inherently broadband and highly efficient class-J PA design targeting future multi-band multi-standard wireless communication protocols.
基金supported by the National Natural Science Foundation of China (21476120)the Shandong Province Prioritized Development Plan (2017GGX40107)the Taishan Scholar Project of Shandong Province in China (ts201511033)
文摘The Br?nsted-acidic polyether ionic liquids(ILs)with different polymerization degrees(n value)were prepared via the reaction of tetramethylguanidine and epoxy ethane,followed by successive reactions with 1,3-propane sultone and trifluoromethanesulfonic acid(TfOH).The prepared ILs were characterized by infrared spectroscopy and 1H nuclear magnetic resonance spectroscopy,and their thermal stability was determined by thermal gravimetry.The synthesized polyether ILs coupled with TfOH were used to catalyze the alkylation reaction of isobutane and isobutene for the preparation of alkylate gasoline.The polyether ILs could improve the substrate dissolution and promote the separation of the catalyst from the products.The ideal IL(n=94)was determined.The optimized alkylation reaction conditions covered:a VTfOH/VIL ratio of 0.35,a reaction temperature of 40℃,a reaction time of 50 min,and a stirring speed of 800 r/min.The conversion of isobutene was 92.4%and the selectivity for the C8-product was 81.6%.Under optimal conditions,the catalyst life was determined and TfOH showed improved cyclic performance in the polyether ILs.After 8 operating cycles,the catalytic activity of the catalyst showed negligible decline.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61575076 and 61804148)the National Key Research and Development Plan of China(Grant No.2016YFB0402502)
文摘The extinction ratio and insertion loss of spatial light modulator are subject to the material problem, thus limiting its applications. One reflection-type silicon-based spatial light modulator with high reflective materials outside the Fabry-Perot cavity is demonstrated in this paper. The reflectivity values of the outside-cavity materials with different film layer numbers are simulated. The reflectivity values of 6-pair Ta2O5/SiO2 films at 1550 nm are experimentally verified to be as high as 99.9%. The surfaces of 6-pair Ta2O5/SiO2 films are smooth: their root-mean-square roughness values are as small as 0.53 nm. The insertion loss of the device at 1550 nm is only 1.2 dB. The high extinction ratio of the device at 1550 nm and 11 V is achieved to be 29.7 dB. The spatial light modulator has a high extinction ratio and low insertion loss for applications.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFB2200103)the National Natural Science Foundation of China(Grant No.61474094)Principal Fund of Minnan Normal University(Grant No.KJ2020006).
文摘A near-infrared germanium(Ge)Schottky photodetector(PD)with an ultrathin silicon(Si)barrier enhancement layer between the indium-doped tin oxide(ITO)electrode and Ge epilayer on Si or silicon-on-insulator(SOI)is proposed and fabricated.The well-behaved ITO/Si cap/Ge Schottky junctions without intentional doping process for the Ge epilayer are formed on the Si and SOI substrates.The Si-and SOI-based ITO/Si cap/Ge Schottky PDs exhibit low dark current densities of 33 mA/cm2 and 44 mA/cm2,respectively.Benefited from the high transmissivity of ITO electrode and the reflectivity of SOI substrate,an optical responsivity of 0.19 A/W at 1550 nm wavelength is obtained for the SOI-based ITO/Si cap/Ge Schottky PD.These complementary metal–oxide–semiconductor(CMOS)compatible Si(or SOI)-based ITO/Si cap/Ge Schottky PDs are quite useful for detecting near-infrared wavelengths with high efficiency.
基金supported in part by the National Natural Science Foundation of China under Grant Nos.62101117 and 62188102in part by ZTE Industry-University-Institute Cooperation Fundsin part by the Project funded by China Postdoctoral Science Foundation under Grant Nos.2021M700763 and 2022T150113.
文摘In view of the existing design challenges for Terahertz(THz)power amplifiers(PAs),the common design methods and the efforts of the State Key Laboratory of Millimeter Wave,Southeast University,China in the development of silicon-based THz PAs,mainly including silicon-based PAs with operating frequencies covering 100–300 GHz,are summarized in this paper.Particularly,we design an LC-balun-based two-stage differential cascode PA with a center frequency of 150 GHz and an output power of 14 dBm.Based on a Marchand balun,we report a 220 GHz three-stage differential cascode PA with a saturated output power of 9.5 dBm.To further increase the output power of THz PA,based on a four-way differential power combining technique,we report a 211–263 GHz dual-LC-tank-based broadband PA with a recorded 14.7 dBm Psat and 16.4 dB peak gain.All the above circuits are designed in a standard 130 nm silicon germanium(SiGe)BiCMOS process.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.92165207,12474490,12034018,and 92265113)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302300)the USTC Tang Scholarship.
文摘Radio frequency(RF)reflectometry is an effective and sensitive technique for detecting charge signal in semiconductor quantum dots,and its measurement bandwidth can reach the MHz level.However,in accumulation mode devices,the presence of parasitic capacitance makes RF reflectometry more difficult.The universal approach is relocating the ion implantation region approximately 10μm from the center of the single-electron transistor(SET)and optimizing the design of the accumulation gates.But,this method puts forward more stringent requirements for micro-nano fabrication processing.Here,we propose a split-gate structure that enables RF reflectometry when the ion-implanted region and the ohmic contact are farther from the SET center.In Si-MOS devices,we employ a split-gate structure to achieve RF detection,with the ion-implanted region located 150μm away from the center of the SET.Within an integration time of 140 nanoseconds,we achieved a readout fidelity exceeding 99.8%and a detection bandwidth of over 2 MHz.This is an alternative solution for micro-nano fabrication processing that cannot achieve ion implantation areas closer to the center of the chip,and is applicable to various silicon-based semiconductor systems.
