Spectrally-selective photodetection plays a crucial role in various applications,including target imaging and environmental monitoring.Traditional deep-ultraviolet(DUV)narrowband photodetection systems consist of broa...Spectrally-selective photodetection plays a crucial role in various applications,including target imaging and environmental monitoring.Traditional deep-ultraviolet(DUV)narrowband photodetection systems consist of broadband photodetectors and filters,which complicates the architecture and constrains imaging quality.Here,we introduce an electronic-grade diamond single-crystal photodetector exhibiting an exceptionally narrow spectral response in the DUV range with a full width at half maximum of 8 nm.By examining diamond photodetectors with varying dislocation densities,we propose that mitigating the defect-induced trapping effect to achieve charge collection narrowing,assisted by free exciton radiative recombination,is an effective strategy for narrowband photodetection.The superior performance of this device is evidenced through the imaging of DUV light sources,showcasing its capability to differentiate between distinct light sources and monitor human-safe sterilization systems.Our findings underscore the promising potential applications of electronicgrade diamond in narrowband photodetection and offer a valuable technique for identifying electronic-grade diamond.展开更多
As the basis of modern electronics and optoelectronics,high-performance,multi-functional p-n junctions have manifested and occupied an important position.However,the performance of the silicon-based p-n junctions decl...As the basis of modern electronics and optoelectronics,high-performance,multi-functional p-n junctions have manifested and occupied an important position.However,the performance of the silicon-based p-n junctions declines gradually as the thickness approaches to few nanometers.The heterojunction constructed by two-dimensional(2D)materials can significantly improve the device performance compared with traditional technologies.Here,we report the In Se-Te type-II van der Waals heterostructures with rectification ratio up to 1.56×10^(7) at drain-source voltage of±2 V.The p-n junction exhibits a photovoltaic and photoelectric effect under different laser wavelengths and densities and has high photoresponsivity and detectivity under low irradiated light power.Moreover,the heterojunction has stable photo/dark current states and good photoelectric switching characteristics.Such high-performance heterostructured device based on 2D materials provides a new way for futural electronic and optoelectronic devices.展开更多
Infrared photodetectors have been used extensively in biomedicine, surveillance, communication and astronomy. However, state of the art technology based on III-V and II-VI compounds still lacks excellent performance f...Infrared photodetectors have been used extensively in biomedicine, surveillance, communication and astronomy. However, state of the art technology based on III-V and II-VI compounds still lacks excellent performance for high-temperature operation. Surface plasmon polaritons (SPPs) have demonstrated their capability in improving the light detection from visible to infrared wave range due to their light confinement in subwavelength scale. Advanced fabrication techniques such as electron-beam lithography (EBL) and focused ion-beam (FIB), and commercially available numerical design tool like Finite-Difference Time-Domain (FDTD) have enabled rapid development of surface plasmon (SP) enhanced photodetectors. In this review article, the basic mechanisms behind the SP-enhanced photodetection, the different type of plasmonic nanostructures utilized for enhancement, and the reported SP-enhanced infrared photodetectors will be discussed.展开更多
Theα-Ga2 O_(3)nanorod array is grown on FTO by hydrothermal and annealing processes.And a self-powered PEDOT:PSS/α-Ga_(2)O_(3)nanorod array/FTO(PGF)photodetector has been demonstrated by spin coating PEDOT:PSS on th...Theα-Ga2 O_(3)nanorod array is grown on FTO by hydrothermal and annealing processes.And a self-powered PEDOT:PSS/α-Ga_(2)O_(3)nanorod array/FTO(PGF)photodetector has been demonstrated by spin coating PEDOT:PSS on theα-Ga_(2)O_(3)nanorod array.Successfully,the PGF photodetector shows solar-blind UV/visible dual-band photodetection.Our device possesses comparable solar-blind UV responsivity(0.18 mA/W at 235 nm)and much faster response speed(0.102 s)than most of the reported self-poweredα-Ga_(2)O_(3)nanorod array solar-blind UV photodetectors.And it presents the featured and distinguished visible band photoresponse with a response speed of 0.136 s at 540 nm.The response time is also much faster than the other non-self-poweredβ-Ga_(2)O_(3)DUV/visible dual-band photodetectors due to the fast-speed separation of photogenerated carries by the built-in electric field in the depletion regions of PEDOT:PSS/α-Ga_(2)O_(3)heterojunction.The results herein may prove a promising way to realize fast-speed self-poweredα-Ga_(2)O_(3)photodetectors with solar-blind UV/visible dual-band photodetection by simple processes for the applications of multiple-target tracking,imaging,machine vision and communication.展开更多
By introducing the two-mode entangled state representation 〈η｜ whose one mode is a fictitious one accompanying the system mode, this paper presents a new approach for deriving density operator for describing contin...By introducing the two-mode entangled state representation 〈η｜ whose one mode is a fictitious one accompanying the system mode, this paper presents a new approach for deriving density operator for describing continuum photodetection process.展开更多
Using a stimulated parametric down-conversion process combined with a conventional detector, we theoretically propose a scheme to realize the stimulated emission-based detector, and investigate the antinormalty ordere...Using a stimulated parametric down-conversion process combined with a conventional detector, we theoretically propose a scheme to realize the stimulated emission-based detector, and investigate the antinormalty ordered correlation function and Fano factor for the coherent field based on it. Such a detection has advantages over the normally ordered one especially when the intensity of the field is weak.展开更多
A novel lateral Si 0 7 Ge 0.3 /Si p i n photodetector which is suitable for high speed operation with low voltage and at 0 7～1 1μm wavelengths is demonstrated.The fabrication of the device is carried ...A novel lateral Si 0 7 Ge 0.3 /Si p i n photodetector which is suitable for high speed operation with low voltage and at 0 7～1 1μm wavelengths is demonstrated.The fabrication of the device is carried out on a SOI substrate by using a UHV/CVD SiGe/Si heteroepitaxy technology and a CMOS/SOI process.Biased at 3 0V,the photodetector attained a responsivity of 0 38A/W at its peak response wavelength 0 93μm and exhibited extremely low dark current of less than 1nA,small parasitic capacitance of less than 1 0pF,and short rise time of 2 5ns.The distinct characteristics and process compatibility make it applicable to integrate the photodetector with other silicon based devices to meet the needs of high speed near infrared signal detections.展开更多
It remains full of challenge for extending short-wave infrared(SWIR)spectral response and weak-light detection in the context of broad spectral responses for phototransistor.In this work,a novel poly(2,5-bis(4-hexyldo...It remains full of challenge for extending short-wave infrared(SWIR)spectral response and weak-light detection in the context of broad spectral responses for phototransistor.In this work,a novel poly(2,5-bis(4-hexyldodecyl)-2,5-dihydro-3,6-di-2-thienyl-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thiophene)(PDPPT3-HDO):COTIC-4F organic bulk-heterojunction is prepared as active layer for bulk heterojunction phototransistors.PDPPT3-HDO serves as a hole transport material,while COTIC-4F enhances the absorption of SWIR light to 1020 nm.As a result,smooth and connected PDPPT3-HDO film is fabricated by blade coating method and exhibits high hole mobility up to 2.34 cm^(2)·V^(-1)·s^(-1) with a current on/off ratio of 4.72×10^(5) in organic thin film transistors.PDPPT3-HDO:COTIC-4F heterojunction phototransistors exhibit high responsivity of 2680 A·W^(-1) to 900 nm and 815 A·W^(-1) to 1020 nm,with fast response time(rise time~20 ms and fall time~100 ms).The photosensitivity of the heterojunction phototransistor improves as the mass ratio of non-fullerene acceptors increases,resulting in an approximately two orders of magnitude enhancement compared to the bare polymer phototransistor.Importantly,the phototransistor exhibits decent responsivity even under ultra-weak light power of 43μW·cm^(-2) to 1020 nm.This work represents a highly effective and general strategy for fabricating efficient and sensitive SWIR light photodetectors.展开更多
Emerging two-dimensional ternary transition metal dichalcogenide alloys have attracted much attention for their unique optical and optoelectronic properties,making them ideal candidates for optoelectronic applications...Emerging two-dimensional ternary transition metal dichalcogenide alloys have attracted much attention for their unique optical and optoelectronic properties,making them ideal candidates for optoelectronic applications.However,a comprehensive understanding of their quantum confinement effects and photoelectronic response characteristics remains crucial for device optimization and performance enhancement.In this study,we employed various spectroscopic techniques to investigate the optical properties and electronic band structures of molybdenum sulfide selenide(MoSSe)films with different layer numbers(4–11 layers).Our results revealed the splitting of Raman modes and shifting of phonon vibrational frequencies with increasing thickness,suggesting that MoSSe has strong interactions within the lattice.The A1g and E2g 1 modes were mainly shifted by internal strain and dielectric screening effect versus thickness,respectively.The redshift phenomenon of A and B excitons with increasing thickness was attributed to the leading effect of quantum confinement on exciton properties and optical band gaps.We observed a strong decrease in the direct bandgap spectral weight in photoluminescence(PL)when the layer number increased from 4 to 5.In addition,we have fabricated MoSSe photodetectors that exhibit a broadband response in the visible wavelength band of 350–800 nm.Furthermore,the observed enhancement in photocurrent and responsivity with increasing film thickness underscored the potential of MoSSebased devices for practical optoelectronic applications.This research contributes to advancing our fundamental understanding of MoSSe materials and paves the way for the design and development of high-performance optoelectronic devices.展开更多
Two-dimensional(2D)semiconductors with intrinsic ferromagnetism are highly desirable for potential applications in nextgeneration spintronic and optoelectronic devices.However,controllable synthesis of intrinsic 2D ma...Two-dimensional(2D)semiconductors with intrinsic ferromagnetism are highly desirable for potential applications in nextgeneration spintronic and optoelectronic devices.However,controllable synthesis of intrinsic 2D magnetic semiconductor on a substrate is still a challenging task.Herein,large-area 2D non-layered rock salt(α-phase)MnSe nanosheets were grown on mica substrates,with the thickness changing from 54.2 to 0.9 nm(one unit cell),by chemical vapour deposition.The X-ray diffraction,Raman spectroscopy,transmission electron microscopy,and X-ray photoelectron spectroscopy measurements confirmed that the resulting 2Dα-MnSe nanosheets were obtained as high-quality single crystals.The magnetic hysteresis loops and synchrotron X-ray measurements directly indicated the anomalous magnetic properties inα-MnSe nanosheets.Comprehensive analysis of the reasons for magnetic property revealed that the low-temperature phase transition,small number of stacking differences in crystals,and surface weak oxidation in(111)-orientedα-MnSe were the main mechanisms.Furthermore,α-MnSe nanosheets exhibited broadband photoresponse from 457 to 671 nm with an outstanding detectivity and responsivity behaviours.This study presents the detailed growth process of ultrathin 2D magnetic semiconductorα-MnSe,and its outstanding magnetic properties and broadband photodetection,which provide an excellent platform for magneto-optical and magneto-optoelectronic research.展开更多
Broadband photodetection,spanning from ultraviolet(UV)to infrared(IR),is pivotal in diverse technological domains including astronomy,remote sensing,environmental monitoring,and medical diagnostics.However,current com...Broadband photodetection,spanning from ultraviolet(UV)to infrared(IR),is pivotal in diverse technological domains including astronomy,remote sensing,environmental monitoring,and medical diagnostics.However,current commercially available broadband photodetectors,predominately based on conventional narrow-bandgap semiconductors,exhibit limited sensitivity in the UV region.This limitation,stemming from the significant energy disparity between the semiconductor bandgap and UV photon,narrows their application scope.Herein,we report an innovative approach involving the in-situ van der Waals(vdW)integration of two-dimensional(2D)GeSe_(2)layers onto a Si substrate.This process yields a high-quality GeSe_(2)/Si vdW heterojunction device,which features a broad response range covering from UV to near-IR(NIR)with a greatly-enhanced sensitivity in the UV region.The device possesses high responsivities of 325 and 533.4 mA/W,large detectivities of 1.24×10^(13)and 2.57×10^(13)Jones,and fast response speeds of 20.6/82.1 and 17.7/81.0μs under 360 and 980 nm,respectively.Notably,the broadband image sensing and secure invisible optical communication capabilities of the GeSe_(2)/Si heterojunction device are demonstrated.Our work provides a viable approach for UV-enhanced broadband photodetection technology,opening up new possibilities and applications across various scientific and technological domains.展开更多
The integration between infrared detection and modern microelectronics offers unique opportunities for compact and high-resolution infrared imaging.However,silicon,the cornerstone of modern microelectronics,can only d...The integration between infrared detection and modern microelectronics offers unique opportunities for compact and high-resolution infrared imaging.However,silicon,the cornerstone of modern microelectronics,can only detect light within a limited wavelength range(<1100 nm)due to its bandgap of 1.12 eV,which restricts its utility in the infrared detection realm.Herein,a photo-driven fin field-effect transistor is presented,which breaks the spectral response constraint of conventional silicon detectors while achieving sensitive infrared detection.This device comprises a fin-shaped silicon channel for charge transport and a lead sulfide film for infrared light harvesting.The lead sulfide film wraps the silicon channel to form a“three-dimensional”infrared-sensitive gate,enabling the photovoltage generated at the lead sulfide-silicon junction to effectively modulate the channel conductance.At room temperature,this device realizes a broadband photodetection from visible(635 nm)to short-wave infrared regions(2700 nm),surpassing the working range of the regular indium gallium arsenide and germanium detectors.Furthermore,it exhibits low equivalent noise powers of 3.2×10^(-12) W·Hz^(-1/2) and 2.3×10^(-11) W·Hz^(-1/2) under 1550 nm and 2700 nm illumination,respectively.These results highlight the significant potential of photo-driven fin field-effect transistors in advancing uncooled silicon-based infrared detection.展开更多
Two-dimensional(2D) atomic crystals,such as graphene,black phosphorus(BP) and transition metal dichalcogenides(TMDCs) are attractive for use in optoelectronic devices,due to their unique crystal structures and optical...Two-dimensional(2D) atomic crystals,such as graphene,black phosphorus(BP) and transition metal dichalcogenides(TMDCs) are attractive for use in optoelectronic devices,due to their unique crystal structures and optical absorption properties.In this study,we fabricated BP/ReS2 van der Waals(vdWs) heterojunction devices.The devices realized broadband photoresponse from visible to near infrared(NIR)(400–1800 nm) with stable and repeatable photoswitch characteristics,and the photoresponsivity reached 1.8 mA/W at 1550 nm.In addition,the polarization sensitive detection in the visible to NIR spectrum(532–1750 nm) was demonstrated,and the photodetector showed a highly polarization sensitive photocurrent with an anisotropy ratio as high as 6.44 at 1064 nm.Our study shows that van der Waals heterojunction is an effective way to realize the broadband polarization sensitive photodetection,which is of great significance to the realization and application of multi-functional devices based on 2D vdWs heterostructures.展开更多
Very small metallic nanostructures,i.e.,plasmonic nanoparticles(NPs),can demonstrate the localized surface plasmon resonance(LSPR)e ect,a characteristic of the strong light absorption,scattering and localized electrom...Very small metallic nanostructures,i.e.,plasmonic nanoparticles(NPs),can demonstrate the localized surface plasmon resonance(LSPR)e ect,a characteristic of the strong light absorption,scattering and localized electromagnetic field via the collective oscillation of surface electrons upon on the excitation by the incident photons.The LSPR of plasmonic NPs can significantly improve the photoresponse of the photodetectors.In this work,significantly enhanced photoresponse of UV photodetectors is demonstrated by the incorporation of various plasmonic NPs in the detector architecture.Various size and elemental composition of monometallic Ag and Au NPs,as well as bimetallic alloy Ag Au NPs,are fabricated on Ga N(0001)by the solid-state dewetting approach.The photoresponse of various NPs are tailored based on the geometric and elemental evolution of NPs,resulting in the highly enhanced photoresponsivity of 112 A W-1,detectivity of 2.4×1012 Jones and external quantum e ciency of 3.6×104%with the high Ag percentage of Ag Au alloy NPs at a low bias of 0.1 V.The Ag Au alloy NP detector also demonstrates a fast photoresponse with the relatively short rise and fall time of less than 160 and 630 ms,respectively.The improved photoresponse with the Ag Au alloy NPs is correlated with the simultaneous e ect of strong plasmon absorption and scattering,increased injection of hot electrons into the Ga N conduction band and reduced barrier height at the alloy NPs/Ga N interface.展开更多
基金supports from Natural Science Foundation of Guangdong Province for Distinguished Young Scholars(Grant No.2021B1515020105).
文摘Spectrally-selective photodetection plays a crucial role in various applications,including target imaging and environmental monitoring.Traditional deep-ultraviolet(DUV)narrowband photodetection systems consist of broadband photodetectors and filters,which complicates the architecture and constrains imaging quality.Here,we introduce an electronic-grade diamond single-crystal photodetector exhibiting an exceptionally narrow spectral response in the DUV range with a full width at half maximum of 8 nm.By examining diamond photodetectors with varying dislocation densities,we propose that mitigating the defect-induced trapping effect to achieve charge collection narrowing,assisted by free exciton radiative recombination,is an effective strategy for narrowband photodetection.The superior performance of this device is evidenced through the imaging of DUV light sources,showcasing its capability to differentiate between distinct light sources and monitor human-safe sterilization systems.Our findings underscore the promising potential applications of electronicgrade diamond in narrowband photodetection and offer a valuable technique for identifying electronic-grade diamond.
基金Project supported by the Ministry of Science and Technology of China(Grant No.2018YFA0305800)the National Natural Science Foundation of China(Grant No.61888102)the Chinese Academy of Sciences(Grant Nos.ZDBSSSW-WHC001,XDB33030100,XDB30000000,and YSBR-003)。
文摘As the basis of modern electronics and optoelectronics,high-performance,multi-functional p-n junctions have manifested and occupied an important position.However,the performance of the silicon-based p-n junctions declines gradually as the thickness approaches to few nanometers.The heterojunction constructed by two-dimensional(2D)materials can significantly improve the device performance compared with traditional technologies.Here,we report the In Se-Te type-II van der Waals heterostructures with rectification ratio up to 1.56×10^(7) at drain-source voltage of±2 V.The p-n junction exhibits a photovoltaic and photoelectric effect under different laser wavelengths and densities and has high photoresponsivity and detectivity under low irradiated light power.Moreover,the heterojunction has stable photo/dark current states and good photoelectric switching characteristics.Such high-performance heterostructured device based on 2D materials provides a new way for futural electronic and optoelectronic devices.
文摘Infrared photodetectors have been used extensively in biomedicine, surveillance, communication and astronomy. However, state of the art technology based on III-V and II-VI compounds still lacks excellent performance for high-temperature operation. Surface plasmon polaritons (SPPs) have demonstrated their capability in improving the light detection from visible to infrared wave range due to their light confinement in subwavelength scale. Advanced fabrication techniques such as electron-beam lithography (EBL) and focused ion-beam (FIB), and commercially available numerical design tool like Finite-Difference Time-Domain (FDTD) have enabled rapid development of surface plasmon (SP) enhanced photodetectors. In this review article, the basic mechanisms behind the SP-enhanced photodetection, the different type of plasmonic nanostructures utilized for enhancement, and the reported SP-enhanced infrared photodetectors will be discussed.
基金Project supported by the National Natural Science Foundation of China(Grant No.61705155)。
文摘Theα-Ga2 O_(3)nanorod array is grown on FTO by hydrothermal and annealing processes.And a self-powered PEDOT:PSS/α-Ga_(2)O_(3)nanorod array/FTO(PGF)photodetector has been demonstrated by spin coating PEDOT:PSS on theα-Ga_(2)O_(3)nanorod array.Successfully,the PGF photodetector shows solar-blind UV/visible dual-band photodetection.Our device possesses comparable solar-blind UV responsivity(0.18 mA/W at 235 nm)and much faster response speed(0.102 s)than most of the reported self-poweredα-Ga_(2)O_(3)nanorod array solar-blind UV photodetectors.And it presents the featured and distinguished visible band photoresponse with a response speed of 0.136 s at 540 nm.The response time is also much faster than the other non-self-poweredβ-Ga_(2)O_(3)DUV/visible dual-band photodetectors due to the fast-speed separation of photogenerated carries by the built-in electric field in the depletion regions of PEDOT:PSS/α-Ga_(2)O_(3)heterojunction.The results herein may prove a promising way to realize fast-speed self-poweredα-Ga_(2)O_(3)photodetectors with solar-blind UV/visible dual-band photodetection by simple processes for the applications of multiple-target tracking,imaging,machine vision and communication.
基金supported by President Foundation of Chinese Academy of Sciencesthe National Natural Science Foundation of China (Grant Nos 10775097 and 10874174)
文摘By introducing the two-mode entangled state representation 〈η｜ whose one mode is a fictitious one accompanying the system mode, this paper presents a new approach for deriving density operator for describing continuum photodetection process.
基金Project supported in part by the National Natural Science Foundation of China (Grant Nos. 10774096 and 60708010)the National Basic Research Program of China (Grant No. 2006CB921101)the Research Fund for the Returned Overseas Chinese Scholars of Shanxi Province,China (Grant No. 200713)
文摘Using a stimulated parametric down-conversion process combined with a conventional detector, we theoretically propose a scheme to realize the stimulated emission-based detector, and investigate the antinormalty ordered correlation function and Fano factor for the coherent field based on it. Such a detection has advantages over the normally ordered one especially when the intensity of the field is weak.
文摘A novel lateral Si 0 7 Ge 0.3 /Si p i n photodetector which is suitable for high speed operation with low voltage and at 0 7～1 1μm wavelengths is demonstrated.The fabrication of the device is carried out on a SOI substrate by using a UHV/CVD SiGe/Si heteroepitaxy technology and a CMOS/SOI process.Biased at 3 0V,the photodetector attained a responsivity of 0 38A/W at its peak response wavelength 0 93μm and exhibited extremely low dark current of less than 1nA,small parasitic capacitance of less than 1 0pF,and short rise time of 2 5ns.The distinct characteristics and process compatibility make it applicable to integrate the photodetector with other silicon based devices to meet the needs of high speed near infrared signal detections.
基金supported by the Ministry of Science and Technology of China(Nos.2017YFA0204503 and 2018YFA0703200)the National Natural Science Foundation of China(Nos.52121002,51733004,51725304,21875158,and U21A6002)+1 种基金Tianjin Natural Science Foundation(No.20JCJQJC00300)the Discretionary Fund of Tianjin University(No.2104).
文摘It remains full of challenge for extending short-wave infrared(SWIR)spectral response and weak-light detection in the context of broad spectral responses for phototransistor.In this work,a novel poly(2,5-bis(4-hexyldodecyl)-2,5-dihydro-3,6-di-2-thienyl-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thiophene)(PDPPT3-HDO):COTIC-4F organic bulk-heterojunction is prepared as active layer for bulk heterojunction phototransistors.PDPPT3-HDO serves as a hole transport material,while COTIC-4F enhances the absorption of SWIR light to 1020 nm.As a result,smooth and connected PDPPT3-HDO film is fabricated by blade coating method and exhibits high hole mobility up to 2.34 cm^(2)·V^(-1)·s^(-1) with a current on/off ratio of 4.72×10^(5) in organic thin film transistors.PDPPT3-HDO:COTIC-4F heterojunction phototransistors exhibit high responsivity of 2680 A·W^(-1) to 900 nm and 815 A·W^(-1) to 1020 nm,with fast response time(rise time~20 ms and fall time~100 ms).The photosensitivity of the heterojunction phototransistor improves as the mass ratio of non-fullerene acceptors increases,resulting in an approximately two orders of magnitude enhancement compared to the bare polymer phototransistor.Importantly,the phototransistor exhibits decent responsivity even under ultra-weak light power of 43μW·cm^(-2) to 1020 nm.This work represents a highly effective and general strategy for fabricating efficient and sensitive SWIR light photodetectors.
基金financially supported by the National Natural Science Foundation of China(U2230108,62275053)the National Key R&D Program of China(2021YFB2012601).
文摘Emerging two-dimensional ternary transition metal dichalcogenide alloys have attracted much attention for their unique optical and optoelectronic properties,making them ideal candidates for optoelectronic applications.However,a comprehensive understanding of their quantum confinement effects and photoelectronic response characteristics remains crucial for device optimization and performance enhancement.In this study,we employed various spectroscopic techniques to investigate the optical properties and electronic band structures of molybdenum sulfide selenide(MoSSe)films with different layer numbers(4–11 layers).Our results revealed the splitting of Raman modes and shifting of phonon vibrational frequencies with increasing thickness,suggesting that MoSSe has strong interactions within the lattice.The A1g and E2g 1 modes were mainly shifted by internal strain and dielectric screening effect versus thickness,respectively.The redshift phenomenon of A and B excitons with increasing thickness was attributed to the leading effect of quantum confinement on exciton properties and optical band gaps.We observed a strong decrease in the direct bandgap spectral weight in photoluminescence(PL)when the layer number increased from 4 to 5.In addition,we have fabricated MoSSe photodetectors that exhibit a broadband response in the visible wavelength band of 350–800 nm.Furthermore,the observed enhancement in photocurrent and responsivity with increasing film thickness underscored the potential of MoSSebased devices for practical optoelectronic applications.This research contributes to advancing our fundamental understanding of MoSSe materials and paves the way for the design and development of high-performance optoelectronic devices.
基金supported by the National Natural Science Foundation of China(Nos.12174237,52002232,and 12304148)Fundamental Research Program of Shanxi Province(202303021221152).
文摘Two-dimensional(2D)semiconductors with intrinsic ferromagnetism are highly desirable for potential applications in nextgeneration spintronic and optoelectronic devices.However,controllable synthesis of intrinsic 2D magnetic semiconductor on a substrate is still a challenging task.Herein,large-area 2D non-layered rock salt(α-phase)MnSe nanosheets were grown on mica substrates,with the thickness changing from 54.2 to 0.9 nm(one unit cell),by chemical vapour deposition.The X-ray diffraction,Raman spectroscopy,transmission electron microscopy,and X-ray photoelectron spectroscopy measurements confirmed that the resulting 2Dα-MnSe nanosheets were obtained as high-quality single crystals.The magnetic hysteresis loops and synchrotron X-ray measurements directly indicated the anomalous magnetic properties inα-MnSe nanosheets.Comprehensive analysis of the reasons for magnetic property revealed that the low-temperature phase transition,small number of stacking differences in crystals,and surface weak oxidation in(111)-orientedα-MnSe were the main mechanisms.Furthermore,α-MnSe nanosheets exhibited broadband photoresponse from 457 to 671 nm with an outstanding detectivity and responsivity behaviours.This study presents the detailed growth process of ultrathin 2D magnetic semiconductorα-MnSe,and its outstanding magnetic properties and broadband photodetection,which provide an excellent platform for magneto-optical and magneto-optoelectronic research.
基金financially supported by the National Natural Science Foundation of China(Nos.62374149,U2004165,and U22A20138)Key Research Project for Higher Education Institutions in Henan Province(No.24B140010).
文摘Broadband photodetection,spanning from ultraviolet(UV)to infrared(IR),is pivotal in diverse technological domains including astronomy,remote sensing,environmental monitoring,and medical diagnostics.However,current commercially available broadband photodetectors,predominately based on conventional narrow-bandgap semiconductors,exhibit limited sensitivity in the UV region.This limitation,stemming from the significant energy disparity between the semiconductor bandgap and UV photon,narrows their application scope.Herein,we report an innovative approach involving the in-situ van der Waals(vdW)integration of two-dimensional(2D)GeSe_(2)layers onto a Si substrate.This process yields a high-quality GeSe_(2)/Si vdW heterojunction device,which features a broad response range covering from UV to near-IR(NIR)with a greatly-enhanced sensitivity in the UV region.The device possesses high responsivities of 325 and 533.4 mA/W,large detectivities of 1.24×10^(13)and 2.57×10^(13)Jones,and fast response speeds of 20.6/82.1 and 17.7/81.0μs under 360 and 980 nm,respectively.Notably,the broadband image sensing and secure invisible optical communication capabilities of the GeSe_(2)/Si heterojunction device are demonstrated.Our work provides a viable approach for UV-enhanced broadband photodetection technology,opening up new possibilities and applications across various scientific and technological domains.
基金supported by the National Key R&D Program of China(2017YFE0131900)the Natural Science Foundation of Chongqing,China(CSTB2023NSCQ-LZX0087)the National Natural Science Foundation of China(62204242,62005182).
文摘The integration between infrared detection and modern microelectronics offers unique opportunities for compact and high-resolution infrared imaging.However,silicon,the cornerstone of modern microelectronics,can only detect light within a limited wavelength range(<1100 nm)due to its bandgap of 1.12 eV,which restricts its utility in the infrared detection realm.Herein,a photo-driven fin field-effect transistor is presented,which breaks the spectral response constraint of conventional silicon detectors while achieving sensitive infrared detection.This device comprises a fin-shaped silicon channel for charge transport and a lead sulfide film for infrared light harvesting.The lead sulfide film wraps the silicon channel to form a“three-dimensional”infrared-sensitive gate,enabling the photovoltage generated at the lead sulfide-silicon junction to effectively modulate the channel conductance.At room temperature,this device realizes a broadband photodetection from visible(635 nm)to short-wave infrared regions(2700 nm),surpassing the working range of the regular indium gallium arsenide and germanium detectors.Furthermore,it exhibits low equivalent noise powers of 3.2×10^(-12) W·Hz^(-1/2) and 2.3×10^(-11) W·Hz^(-1/2) under 1550 nm and 2700 nm illumination,respectively.These results highlight the significant potential of photo-driven fin field-effect transistors in advancing uncooled silicon-based infrared detection.
基金supported by the National Key R&D Program of China (Grant No. 2017YFA0303400 and No.2017YFB 0405700)supported by the NSFC Grant Nos. 61774144 and 11474272sponsored by Chinese Academy of Sciences, grant No. QYZDY-SSW-JSC020, XDPB12, and XDB28000000
文摘Two-dimensional(2D) atomic crystals,such as graphene,black phosphorus(BP) and transition metal dichalcogenides(TMDCs) are attractive for use in optoelectronic devices,due to their unique crystal structures and optical absorption properties.In this study,we fabricated BP/ReS2 van der Waals(vdWs) heterojunction devices.The devices realized broadband photoresponse from visible to near infrared(NIR)(400–1800 nm) with stable and repeatable photoswitch characteristics,and the photoresponsivity reached 1.8 mA/W at 1550 nm.In addition,the polarization sensitive detection in the visible to NIR spectrum(532–1750 nm) was demonstrated,and the photodetector showed a highly polarization sensitive photocurrent with an anisotropy ratio as high as 6.44 at 1064 nm.Our study shows that van der Waals heterojunction is an effective way to realize the broadband polarization sensitive photodetection,which is of great significance to the realization and application of multi-functional devices based on 2D vdWs heterostructures.
基金Financial support from the National Research Foundation of Korea(NRF)Grant funded by the Korean Government(MSIP)(Nos.NRF-2019R1A2C4069438 and NRF-2018R1A6A1A03025242)in part by the research grant of Kwangwoon University in 2020.
文摘Very small metallic nanostructures,i.e.,plasmonic nanoparticles(NPs),can demonstrate the localized surface plasmon resonance(LSPR)e ect,a characteristic of the strong light absorption,scattering and localized electromagnetic field via the collective oscillation of surface electrons upon on the excitation by the incident photons.The LSPR of plasmonic NPs can significantly improve the photoresponse of the photodetectors.In this work,significantly enhanced photoresponse of UV photodetectors is demonstrated by the incorporation of various plasmonic NPs in the detector architecture.Various size and elemental composition of monometallic Ag and Au NPs,as well as bimetallic alloy Ag Au NPs,are fabricated on Ga N(0001)by the solid-state dewetting approach.The photoresponse of various NPs are tailored based on the geometric and elemental evolution of NPs,resulting in the highly enhanced photoresponsivity of 112 A W-1,detectivity of 2.4×1012 Jones and external quantum e ciency of 3.6×104%with the high Ag percentage of Ag Au alloy NPs at a low bias of 0.1 V.The Ag Au alloy NP detector also demonstrates a fast photoresponse with the relatively short rise and fall time of less than 160 and 630 ms,respectively.The improved photoresponse with the Ag Au alloy NPs is correlated with the simultaneous e ect of strong plasmon absorption and scattering,increased injection of hot electrons into the Ga N conduction band and reduced barrier height at the alloy NPs/Ga N interface.
