β-Ga_(2)O_(3),as one of the important 4th generation semiconductors,is widely used in solar-blind ultraviolet(UV)detectors with a short detection range of 200-280 nm benefiting from its ultra-wide bandgap,strong radi...β-Ga_(2)O_(3),as one of the important 4th generation semiconductors,is widely used in solar-blind ultraviolet(UV)detectors with a short detection range of 200-280 nm benefiting from its ultra-wide bandgap,strong radiation resistance,and excellent chemical and thermal stabilities.Here,a self-powered photodetector(PD)based on an Ag/β-Ga_(2)O_(3) Schottky heterojunction was designed and fabricated.Through a subtle design of electrodes,the pyro-phototronic effect was discovered,which can be coupled to the common photovoltaic effect and further enhance the performance of the PD.Compared to traditional Ga_(2)O_(3)-based PD,the as-used PD exhibited a self-driving property and a broadband response beyond the bandgap lim-itations,ranging from 200 nm(deep UV)to 980 nm(infrared).Moreover,the photoresponse time was greatly shrunk owing to the coupling effect.Under laser irradiation,with a wavelength of 450 nm and a power density of 8 mW cm-2,the photocurrent could be improved by around 41 times compared with the sole photovoltaic effect.Besides,the performances of the Schottky PD were enhanced at both high and low temperatures.The device also possessed long-term working stability.This paper not only re-veals basic physics lying in the 4th generation semiconductor Ga_(2)O_(3) but also sheds light on the multi-encryption transmission of light information using this PD.展开更多
Carbon hollow microspheres as microwave absorption materials(MAMs)are of great significance in the research focuses owing to their lightweight,good impedance matching,and modifiable dielectric proper-ties.However,it i...Carbon hollow microspheres as microwave absorption materials(MAMs)are of great significance in the research focuses owing to their lightweight,good impedance matching,and modifiable dielectric proper-ties.However,it is still a huge challenge to distinguish the contribution of dielectric attenuation between carbon intrinsic feature and hollow structure due to the lack of appropriate model materials.Then,the inadequate analysis of effective dielectric attenuation resulted in the construction of carbon hollow mi-crospheres semiempirical and often lacked precise modification of microstructure.Herein,a series of car-bon hollow microspheres with controllable graphitization and thickness of shell derived from phenolic resin coated on polystyrene microspheres that fully decomposed were synthesized,which is free of the impact of template residue.The carbon fragments ground from hollow microspheres exhibit the same broadband response as hollow microspheres,with effective bandwidth(RL<-10 dB)of 7.6 GHz,while their electromagnetic wave loss mechanisms are distinct.The high dielectric loss of carbon fragments with the same intrinsic characteristics as carbon hollow microspheres is mainly caused by dipole po-larization relaxation and enhancement of electrical conductivity ascribed to overlapping between carbon sheets.For the hollow structure,in addition to dipole polarization relaxation attributed to carbon intrin-sic feature,the effective dielectric loss is also comprised of the interfacial polarization in advantage due to the effective heterogeneous interface between air and carbon shell.This work provides a simplified model to clarify the effect of carbon intrinsic feature and microstructure on the dielectric loss of carbon hollow microspheres.展开更多
In this paper, a novel magnetoelectric（ME） composite structure is proposed, and the ME response in the structure is measured at the bias magnetic field up to 2000 Oe（1 Oe = 79.5775 A·m^（-1）） and the excitat...In this paper, a novel magnetoelectric（ME） composite structure is proposed, and the ME response in the structure is measured at the bias magnetic field up to 2000 Oe（1 Oe = 79.5775 A·m^（-1）） and the excitation frequency of alternating magnetic field ranging from 1 kHz to 200 kHz. The ME voltage of each PZT layer is detected. According to the measurement results, the phase differences are observed among three channels and the multi-peak phenomenon appears in each channel. Meanwhile, the results show that the ME structure can stay a relatively high ME response within a wide bandwidth.Besides, the hysteretic loops of three PZT layers are observed. When the frequency of alternating current（AC） magnetic field changes, the maximum value of ME coefficient appears in different layers due to the multiple vibration modes of the structure. Moreover, a finite element analysis is performed to evaluate the resonant frequency of the structure, and the theoretical calculating results accord well with the experimental results. The experiment results suggest that the proposed structure may be a good candidate for designing broadband magnetic field sensors.展开更多
Bi-doped glass fibers with controllable optical response are essential for next-generation broadband amplifiers and tunable lasers.However,achieving broad wavelength tunability and stable near-infrared(NIR)emission re...Bi-doped glass fibers with controllable optical response are essential for next-generation broadband amplifiers and tunable lasers.However,achieving broad wavelength tunability and stable near-infrared(NIR)emission remains challenging due to limited structural modification of conventional silica glasses and variability of Bi active centers(BACs).Here,we propose a cation hybridization strategy to overcome these issues,demonstrating an enhanced ultra-broadband,multi-band NIR optical response in Bi-doped photonic glasses.Alkaline earth metal ions,such as Mg^(2+)and Ba^(2+),were employed as the hybrid cations to“repair”(Mg^(2+))and“tailor”(Ba^(2+))the flexible glass network of germanate glasses,enabling precise customization of the local environment to stabilize different BACs.Impressively,this enables a tunable optical response,ranging from one main peak emission at 1142 nm to a stable multi-band emission spanning 920,1142,1265,and 1516 nm,with an emission bandwidth of 526 nm,which is distinct from conventional rare-earth ions doped glasses.Furthermore,Bi-doped hybrid germanate glass fibers were fabricated and a positive on-off gain in multiple communication bands(O+E+S+C bands)was successfully achieved.The results offer new insights into the Bi NIR luminescence behavior and introduce a promising strategy for developing advanced photonic glass materials.展开更多
Application of novel radio technologies and equip-ment inevitably leads to electromagnetic pollution.One-dimensional polymer-based composite membrane structures have been shown to be an effective strategy to obtain hi...Application of novel radio technologies and equip-ment inevitably leads to electromagnetic pollution.One-dimensional polymer-based composite membrane structures have been shown to be an effective strategy to obtain high-performance microwave absorbers.Herein,we reported a one-dimensional N-doped carbon nanofibers material which encapsulated the hollow Co_(3)SnC_(0.7) nano-cubes in the fiber lumen by electrospinning.Space charge stacking formed between nanoparticles can be channeled by longitudinal fibrous structures.The dielectric constant of the fibers is highly related to the carbonization temperature,and the great impedance matching can be achieved by synergetic effect between Co_(3)SnC_(0.7) and carbon network.At 800℃,the necklace-like Co_(3)SnC_(0.7)/CNF with 5%low load achieves an excellent RL value of−51.2 dB at 2.3 mm and the effective absorption bandwidth of 7.44 GHz with matching thickness of 2.5 mm.The multiple electromagnetic wave(EMW)reflections and interfacial polarization between the fibers and the fibers internal contribute a major effect to attenuating the EMW.These strategies for regulating electromagnetic performance can be expanded to other electromagnetic functional materials which facilitate the development of emerging absorbers.展开更多
Gapless linear energy dispersion of graphene endows it with unique nonlinear optical properties, including broadband nonlinear absorption and giant nonlinear refractive index. Herein, we experimentally observed that f...Gapless linear energy dispersion of graphene endows it with unique nonlinear optical properties, including broadband nonlinear absorption and giant nonlinear refractive index. Herein, we experimentally observed that fewlayers graphene has obvious nonlinear absorption and large nonlinear refraction, as investigated by the Z-scan technique in the mid-infrared（mid-IR） regime. Our study may not only, for the first time to our knowledge, verify the giant nonlinear refractive index of graphene(～10-7cm2∕W) at the mid-IR, which is 7 orders of magnitude larger than other conventional bulk materials, but also provide some new insights for graphene-based mid-IR photonics,potentially leading to the emergence of several new conceptual mid-IR optoelectronics devices.展开更多
Room-temperature(RT)terahertz(THz)detection finds widespread applications in security inspection,communication,biomedical imaging,and scientific research.However,the state-of-the-art detection strategies are still lim...Room-temperature(RT)terahertz(THz)detection finds widespread applications in security inspection,communication,biomedical imaging,and scientific research.However,the state-of-the-art detection strategies are still limited by issues such as low sensitivity,narrow response range,slow response speed,complex fabrication techniques,and difficulties in scaling up to large arrays.Here,we present a high-sensitivity,broadband-response,and high-speed RT THz detection strategy by utilizing a deep subwavelength metal–semiconductor–metal(MSM)structure.The spontaneously formed 2-dimensional electron gas(2DEG)at the CdTe/PbTe interface provides a superior transport channel characterized by high carrier concentration,low scattering,and high mobility.The synergy of the electromagnetic induced well effect formed in the MSM structure,and the efficient and rapid transport capabilities of the 2DEG channel give rise to an impressive performance improvement.The proposed 2DEG photodetector exhibits a broad frequency range from 22 to 519 GHz,an ultralow noise equivalent power of 3.0×10^(−14)W Hz^(−1/2)at 166 GHz,and a short response time of 6.7μs.This work provides an effective route for the development of high-performance RT THz detection strategies,paving the way for enhanced THz technology applications.展开更多
PtTe_(2),as a two-dimensional(2D)material with unique physicochemical properties,has become a key research object that researchers focus on.In this paper,the PtTe_(2)thin film photodetectors are fabricated through the...PtTe_(2),as a two-dimensional(2D)material with unique physicochemical properties,has become a key research object that researchers focus on.In this paper,the PtTe_(2)thin film photodetectors are fabricated through the chemical vapor deposition technique.The surface morphology of the PtTe_(2)thin films is uniform,and the films can be densely packed,effectively reducing the electronic defects and carrier scattering,which can improve the photoelectric conversion process,the response speed,and the sensitivity.The PtTe_(2)device demonstrates a broadband spectral response spanning from ultraviolet(UV)to near-infrared(NIR)wavelengths.Under irradiation with lasers at 375,532,and 808 nm,the 6.9 nm thin film PtTe_(2)device exhibits a positive photoconductivity phenomenon.The photoresponsivity,specific detectivity,and the device's response time for a single cycle under the 375 nm laser irradiation were found to be 2.39 A/W,4.01×10^(10)Jones,and 0.21/0.20 s,respectively.Furthermore,a single-site scanning imaging system using a PtTe_(2)photodetector has been developed.High-resolution images of three characters,"U,""J,"and"S,"have been successfully achieved under 532 nm laser radiation.This work provides valuable experience for the application of the 2D material PtTe_(2)in the fields of optical detection,optical sensing,and optical communication.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.52192610 and 52192613)the National Key R&D Project from the Minister of Science and Technology(No.2021YFA1201601)the CAS-TWAS President’s Fellow-ship(A.B).
文摘β-Ga_(2)O_(3),as one of the important 4th generation semiconductors,is widely used in solar-blind ultraviolet(UV)detectors with a short detection range of 200-280 nm benefiting from its ultra-wide bandgap,strong radiation resistance,and excellent chemical and thermal stabilities.Here,a self-powered photodetector(PD)based on an Ag/β-Ga_(2)O_(3) Schottky heterojunction was designed and fabricated.Through a subtle design of electrodes,the pyro-phototronic effect was discovered,which can be coupled to the common photovoltaic effect and further enhance the performance of the PD.Compared to traditional Ga_(2)O_(3)-based PD,the as-used PD exhibited a self-driving property and a broadband response beyond the bandgap lim-itations,ranging from 200 nm(deep UV)to 980 nm(infrared).Moreover,the photoresponse time was greatly shrunk owing to the coupling effect.Under laser irradiation,with a wavelength of 450 nm and a power density of 8 mW cm-2,the photocurrent could be improved by around 41 times compared with the sole photovoltaic effect.Besides,the performances of the Schottky PD were enhanced at both high and low temperatures.The device also possessed long-term working stability.This paper not only re-veals basic physics lying in the 4th generation semiconductor Ga_(2)O_(3) but also sheds light on the multi-encryption transmission of light information using this PD.
基金National Natural Science Foundation of China(grant No.51802278)Natural Science Foundation of Hebei Province(grant Nos.B2021203012,E2022203082)Department of Education of Hebei Province(grant No.QN2021140).
文摘Carbon hollow microspheres as microwave absorption materials(MAMs)are of great significance in the research focuses owing to their lightweight,good impedance matching,and modifiable dielectric proper-ties.However,it is still a huge challenge to distinguish the contribution of dielectric attenuation between carbon intrinsic feature and hollow structure due to the lack of appropriate model materials.Then,the inadequate analysis of effective dielectric attenuation resulted in the construction of carbon hollow mi-crospheres semiempirical and often lacked precise modification of microstructure.Herein,a series of car-bon hollow microspheres with controllable graphitization and thickness of shell derived from phenolic resin coated on polystyrene microspheres that fully decomposed were synthesized,which is free of the impact of template residue.The carbon fragments ground from hollow microspheres exhibit the same broadband response as hollow microspheres,with effective bandwidth(RL<-10 dB)of 7.6 GHz,while their electromagnetic wave loss mechanisms are distinct.The high dielectric loss of carbon fragments with the same intrinsic characteristics as carbon hollow microspheres is mainly caused by dipole po-larization relaxation and enhancement of electrical conductivity ascribed to overlapping between carbon sheets.For the hollow structure,in addition to dipole polarization relaxation attributed to carbon intrin-sic feature,the effective dielectric loss is also comprised of the interfacial polarization in advantage due to the effective heterogeneous interface between air and carbon shell.This work provides a simplified model to clarify the effect of carbon intrinsic feature and microstructure on the dielectric loss of carbon hollow microspheres.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11702120,11372120,11421062,and 11572143)the Fundamental Research Funds for the Central Universities,China(Grant No.lzujbky-2016-106)
文摘In this paper, a novel magnetoelectric（ME） composite structure is proposed, and the ME response in the structure is measured at the bias magnetic field up to 2000 Oe（1 Oe = 79.5775 A·m^（-1）） and the excitation frequency of alternating magnetic field ranging from 1 kHz to 200 kHz. The ME voltage of each PZT layer is detected. According to the measurement results, the phase differences are observed among three channels and the multi-peak phenomenon appears in each channel. Meanwhile, the results show that the ME structure can stay a relatively high ME response within a wide bandwidth.Besides, the hysteretic loops of three PZT layers are observed. When the frequency of alternating current（AC） magnetic field changes, the maximum value of ME coefficient appears in different layers due to the multiple vibration modes of the structure. Moreover, a finite element analysis is performed to evaluate the resonant frequency of the structure, and the theoretical calculating results accord well with the experimental results. The experiment results suggest that the proposed structure may be a good candidate for designing broadband magnetic field sensors.
基金supported by the National Natural Science Foundation of China(62405092,62122027,62075063,62205109)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(GZC20230852)the Guangdong Basic and Applied Basic Research Foundation(2025A1515010444).
文摘Bi-doped glass fibers with controllable optical response are essential for next-generation broadband amplifiers and tunable lasers.However,achieving broad wavelength tunability and stable near-infrared(NIR)emission remains challenging due to limited structural modification of conventional silica glasses and variability of Bi active centers(BACs).Here,we propose a cation hybridization strategy to overcome these issues,demonstrating an enhanced ultra-broadband,multi-band NIR optical response in Bi-doped photonic glasses.Alkaline earth metal ions,such as Mg^(2+)and Ba^(2+),were employed as the hybrid cations to“repair”(Mg^(2+))and“tailor”(Ba^(2+))the flexible glass network of germanate glasses,enabling precise customization of the local environment to stabilize different BACs.Impressively,this enables a tunable optical response,ranging from one main peak emission at 1142 nm to a stable multi-band emission spanning 920,1142,1265,and 1516 nm,with an emission bandwidth of 526 nm,which is distinct from conventional rare-earth ions doped glasses.Furthermore,Bi-doped hybrid germanate glass fibers were fabricated and a positive on-off gain in multiple communication bands(O+E+S+C bands)was successfully achieved.The results offer new insights into the Bi NIR luminescence behavior and introduce a promising strategy for developing advanced photonic glass materials.
基金financially supported by the Natural Science Foundation of Shandong Province (No. ZR2019YQ24)Taishan Scholars and Young Experts Program of Shandong Province (No.tsqn202103057)+1 种基金the Qingchuang Talents Induction Program of Shandong Higher Education Institution (Research and Innovation Team of Structural-Functional Polymer Composites)Special Financial of Shandong Province (Structural Design of High-efficiency Electromagnetic Wave-absorbing Composite Materials and Construction of Shandong Provincial Talent Teams)
文摘Application of novel radio technologies and equip-ment inevitably leads to electromagnetic pollution.One-dimensional polymer-based composite membrane structures have been shown to be an effective strategy to obtain high-performance microwave absorbers.Herein,we reported a one-dimensional N-doped carbon nanofibers material which encapsulated the hollow Co_(3)SnC_(0.7) nano-cubes in the fiber lumen by electrospinning.Space charge stacking formed between nanoparticles can be channeled by longitudinal fibrous structures.The dielectric constant of the fibers is highly related to the carbonization temperature,and the great impedance matching can be achieved by synergetic effect between Co_(3)SnC_(0.7) and carbon network.At 800℃,the necklace-like Co_(3)SnC_(0.7)/CNF with 5%low load achieves an excellent RL value of−51.2 dB at 2.3 mm and the effective absorption bandwidth of 7.44 GHz with matching thickness of 2.5 mm.The multiple electromagnetic wave(EMW)reflections and interfacial polarization between the fibers and the fibers internal contribute a major effect to attenuating the EMW.These strategies for regulating electromagnetic performance can be expanded to other electromagnetic functional materials which facilitate the development of emerging absorbers.
基金supported by the National 973 Program of China (Grant No. 2012CB315701)the National Natural Science Foundation of China (Grant Nos. 61205125, 61222505, and 61475102)
文摘Gapless linear energy dispersion of graphene endows it with unique nonlinear optical properties, including broadband nonlinear absorption and giant nonlinear refractive index. Herein, we experimentally observed that fewlayers graphene has obvious nonlinear absorption and large nonlinear refraction, as investigated by the Z-scan technique in the mid-infrared（mid-IR） regime. Our study may not only, for the first time to our knowledge, verify the giant nonlinear refractive index of graphene(～10-7cm2∕W) at the mid-IR, which is 7 orders of magnitude larger than other conventional bulk materials, but also provide some new insights for graphene-based mid-IR photonics,potentially leading to the emergence of several new conceptual mid-IR optoelectronics devices.
基金supported by the National Natural Science Foundation of China(11933006,61805060,U2141240,and 62175045)National Key Research and Development Project of China(2023YFB2806700)+5 种基金Zhejiang Provincial Natural Science Foundation of China(LGF21F050001)Hangzhou Science and Technology Bureau of Zhejiang Province(TD2020002)Hangzhou Key Research and Development Program(2024SZD1A39)Research Funds of Hangzhou Institute for Advanced Study(B02006C019019 and 2022ZZ01007)Zhejiang Provincial Natural Science Foundation of China(no.LD25F040001)Hangzhou Joint Fund of the Zhejiang Provincial Natural Science Foundation of China(no.LHZQN25F050001).
文摘Room-temperature(RT)terahertz(THz)detection finds widespread applications in security inspection,communication,biomedical imaging,and scientific research.However,the state-of-the-art detection strategies are still limited by issues such as low sensitivity,narrow response range,slow response speed,complex fabrication techniques,and difficulties in scaling up to large arrays.Here,we present a high-sensitivity,broadband-response,and high-speed RT THz detection strategy by utilizing a deep subwavelength metal–semiconductor–metal(MSM)structure.The spontaneously formed 2-dimensional electron gas(2DEG)at the CdTe/PbTe interface provides a superior transport channel characterized by high carrier concentration,low scattering,and high mobility.The synergy of the electromagnetic induced well effect formed in the MSM structure,and the efficient and rapid transport capabilities of the 2DEG channel give rise to an impressive performance improvement.The proposed 2DEG photodetector exhibits a broad frequency range from 22 to 519 GHz,an ultralow noise equivalent power of 3.0×10^(−14)W Hz^(−1/2)at 166 GHz,and a short response time of 6.7μs.This work provides an effective route for the development of high-performance RT THz detection strategies,paving the way for enhanced THz technology applications.
基金supported by the National Natural Science Foundation of China(No.12104508)the Natural Science Foundation of Jiangsu Province(Nos.BK20180862 and BK20190839)+1 种基金the China Postdoctoral Science Foundation(No.2019M651725)the Anhui Key Laboratory of Photonic Devices and Materials Science(No.AHKL2024KF01)。
文摘PtTe_(2),as a two-dimensional(2D)material with unique physicochemical properties,has become a key research object that researchers focus on.In this paper,the PtTe_(2)thin film photodetectors are fabricated through the chemical vapor deposition technique.The surface morphology of the PtTe_(2)thin films is uniform,and the films can be densely packed,effectively reducing the electronic defects and carrier scattering,which can improve the photoelectric conversion process,the response speed,and the sensitivity.The PtTe_(2)device demonstrates a broadband spectral response spanning from ultraviolet(UV)to near-infrared(NIR)wavelengths.Under irradiation with lasers at 375,532,and 808 nm,the 6.9 nm thin film PtTe_(2)device exhibits a positive photoconductivity phenomenon.The photoresponsivity,specific detectivity,and the device's response time for a single cycle under the 375 nm laser irradiation were found to be 2.39 A/W,4.01×10^(10)Jones,and 0.21/0.20 s,respectively.Furthermore,a single-site scanning imaging system using a PtTe_(2)photodetector has been developed.High-resolution images of three characters,"U,""J,"and"S,"have been successfully achieved under 532 nm laser radiation.This work provides valuable experience for the application of the 2D material PtTe_(2)in the fields of optical detection,optical sensing,and optical communication.
