In many industries,there is a growing demand for semiconductor pressure sensors capable of operating in harsh environments with extremely high and low temperatures and high vibrations.Utilizing the piezoresistive effe...In many industries,there is a growing demand for semiconductor pressure sensors capable of operating in harsh environments with extremely high and low temperatures and high vibrations.Utilizing the piezoresistive effect of heavily doped N-type 4H-SiC,we proposed a family design of eight pressure sensor chip structures featuring different diaphragm shapes of circles and squares,along with different piezoresistor configurations.The 4H-SiC piezoresistive pressure sensor was developed using micro-electromechanical systems(MEMS)technology and encapsulated in a leadless package structure via low-stress connection achieved by glass frit sintering.The 4H-SiC pressure sensor demonstrates impressive performance,exhibiting an accuracy of 0.18%FSO and a temperature tolerance range from−50 to 600°C,with a temperature coefficient of zero output as low as 0.08%/°C at 600°C.Furthermore,the developed sensor shows remarkable stability under conditions of high-temperature vibration coupling.The advancement of this family of 4H-SiC pressure sensors provides a promising solution for pressure measurement in harsh industrial environments.展开更多
Microwave antennas are essential elements for various applications,such as telecommunication,radar,sensing,and wireless power transport.These antennas are conventionally manufactured on rigid substrates using opaque m...Microwave antennas are essential elements for various applications,such as telecommunication,radar,sensing,and wireless power transport.These antennas are conventionally manufactured on rigid substrates using opaque materials,such as metal strips,metallic tapes,or epoxy pastes;thus,prohibiting their use in flexible and wearable devices,and simultaneously limiting their integration into existing optoelectronic systems.Here,we demonstrate that mechanically flexible and optically transparent microwave antennas with high operational efficiencies can be readily fabricated using composite nanolayers deposited on common plastic substrates.The composite nanolayer structure consists of an ultra-thin copper-doped silver film sandwiched between two dielectric films of tantalum pentoxide and aluminum oxide.The material and thickness of each constituent layer are judiciously selected such that the whole structure exhibits an experimentally measured averaged visible transmittance as high as 98.94%compared to a bare plastic substrate,and simultaneously,a sheet resistance as low as 12.5Ω/sq.Four representative types of microwave antennas are implemented:an omnidirectional dipole antenna,unidirectional Yagi-Uda antenna,low-profile patch antenna,and Fabry-Pérot cavity antenna.These devices exhibit great mechanical flexibility with bending angle over 70°,high gain of up to 13.6 dBi,and large radiation efficiency of up to 84.5%.The proposed nano-engineered composites can be easily prepared over large areas on various types of substrates and simultaneously overcome the limitations of poor mechanical flexibility,low electrical conductivity,and reduced optical transparency usually faced by other constituent materials for flexible transparent microwave antennas.The demonstrated flexible microwave antennas have various applications ranging from fifth-generation and vehicular communication systems to bio-signal monitors and wearable electronics.展开更多
In this paper,we introduce an ultra-sensitive optical sensing platform based on the parity-time-reciprocal scaling(PT^-symmetric non-Hermitian metasurfaces,which leverage exotic singularities,such as the exceptional p...In this paper,we introduce an ultra-sensitive optical sensing platform based on the parity-time-reciprocal scaling(PT^-symmetric non-Hermitian metasurfaces,which leverage exotic singularities,such as the exceptional point(EP)and the coherent perfect absorber-laser(CPAL)point,to significantly enhance the sensitivity and detectability of photonic sensors.We theoretically studied scattering properties and physical limitations of the PTX-symmetric metasurface sensing systems with an asymmetric,unbalanced gain-loss profile.The PTLY-symmetric metasurfaces can exhibit similar scattering properties as their Pr-symmetric counterparts at singular points,while achieving a higher sensitivity and a larger modulation depth,possible with the reciprocal-scaling factor(i.e.,X transformation).Specifically,with the optimal reciprocalscaling factor or near-zero phase offset,the proposed PTX-symmetric metasurface sensors operating around the EP or CPAL point may achieve an over 100 dB modulation depth,thus paving a promising route toward the detection of small-scale perturbations caused by,for example,molecular,gaseous,and biochemical surface adsorbates.展开更多
基金supported by the National Natural Science Foundation of China(62401451,62131017)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(GZB20230584)the China Postdoctoral Science Foundation(2024M762579)。
文摘In many industries,there is a growing demand for semiconductor pressure sensors capable of operating in harsh environments with extremely high and low temperatures and high vibrations.Utilizing the piezoresistive effect of heavily doped N-type 4H-SiC,we proposed a family design of eight pressure sensor chip structures featuring different diaphragm shapes of circles and squares,along with different piezoresistor configurations.The 4H-SiC piezoresistive pressure sensor was developed using micro-electromechanical systems(MEMS)technology and encapsulated in a leadless package structure via low-stress connection achieved by glass frit sintering.The 4H-SiC pressure sensor demonstrates impressive performance,exhibiting an accuracy of 0.18%FSO and a temperature tolerance range from−50 to 600°C,with a temperature coefficient of zero output as low as 0.08%/°C at 600°C.Furthermore,the developed sensor shows remarkable stability under conditions of high-temperature vibration coupling.The advancement of this family of 4H-SiC pressure sensors provides a promising solution for pressure measurement in harsh industrial environments.
文摘Microwave antennas are essential elements for various applications,such as telecommunication,radar,sensing,and wireless power transport.These antennas are conventionally manufactured on rigid substrates using opaque materials,such as metal strips,metallic tapes,or epoxy pastes;thus,prohibiting their use in flexible and wearable devices,and simultaneously limiting their integration into existing optoelectronic systems.Here,we demonstrate that mechanically flexible and optically transparent microwave antennas with high operational efficiencies can be readily fabricated using composite nanolayers deposited on common plastic substrates.The composite nanolayer structure consists of an ultra-thin copper-doped silver film sandwiched between two dielectric films of tantalum pentoxide and aluminum oxide.The material and thickness of each constituent layer are judiciously selected such that the whole structure exhibits an experimentally measured averaged visible transmittance as high as 98.94%compared to a bare plastic substrate,and simultaneously,a sheet resistance as low as 12.5Ω/sq.Four representative types of microwave antennas are implemented:an omnidirectional dipole antenna,unidirectional Yagi-Uda antenna,low-profile patch antenna,and Fabry-Pérot cavity antenna.These devices exhibit great mechanical flexibility with bending angle over 70°,high gain of up to 13.6 dBi,and large radiation efficiency of up to 84.5%.The proposed nano-engineered composites can be easily prepared over large areas on various types of substrates and simultaneously overcome the limitations of poor mechanical flexibility,low electrical conductivity,and reduced optical transparency usually faced by other constituent materials for flexible transparent microwave antennas.The demonstrated flexible microwave antennas have various applications ranging from fifth-generation and vehicular communication systems to bio-signal monitors and wearable electronics.
文摘In this paper,we introduce an ultra-sensitive optical sensing platform based on the parity-time-reciprocal scaling(PT^-symmetric non-Hermitian metasurfaces,which leverage exotic singularities,such as the exceptional point(EP)and the coherent perfect absorber-laser(CPAL)point,to significantly enhance the sensitivity and detectability of photonic sensors.We theoretically studied scattering properties and physical limitations of the PTX-symmetric metasurface sensing systems with an asymmetric,unbalanced gain-loss profile.The PTLY-symmetric metasurfaces can exhibit similar scattering properties as their Pr-symmetric counterparts at singular points,while achieving a higher sensitivity and a larger modulation depth,possible with the reciprocal-scaling factor(i.e.,X transformation).Specifically,with the optimal reciprocalscaling factor or near-zero phase offset,the proposed PTX-symmetric metasurface sensors operating around the EP or CPAL point may achieve an over 100 dB modulation depth,thus paving a promising route toward the detection of small-scale perturbations caused by,for example,molecular,gaseous,and biochemical surface adsorbates.
