The fabrication and characterization of a Schottky-emitter heterojunction-collector UV-enhanced bipolar phototransistor （SHBT） are presented. The luminescence peak of the ZnO film is observed at 371nm in the PL spec...The fabrication and characterization of a Schottky-emitter heterojunction-collector UV-enhanced bipolar phototransistor （SHBT） are presented. The luminescence peak of the ZnO film is observed at 371nm in the PL spectrum. The sensitivity of the ultraviolet response from 200 to 400nm is enhanced noticeably, and the spectrum response at wavelengths longer than 400nm is also retained, The experiments show that the Au/n-ZnO/p-Si SHBT UV enhanced phototransistor enhances the sensitivity of the ultraviolet response noticeably. The UV response sensitivity at 370nm of the phototransistor is 5-10 times that of a ZnO/Si heterojunction UV enhanced photodiode.展开更多
Ternary transition metal dichalcogenide alloys with spatially graded bandgaps are an emerging class of two-dimensional materials with unique features,which opens up new potential for device applications.Here,visible–...Ternary transition metal dichalcogenide alloys with spatially graded bandgaps are an emerging class of two-dimensional materials with unique features,which opens up new potential for device applications.Here,visible–near-infrared and self-powered phototransistors based on spatially bandgap-graded MoS2(1−x)Se2x alloys,synthesized by a simple and controllable chemical solution deposition method,are reported.The graded bandgaps,arising from the spatial grading of Se composition and thickness within a single domain,are tuned from 1.83 to 1.73 eV,leading to the formation of a homojunction with a builtin electric field.Consequently,a strong and sensitive gate-modulated photovoltaic effect is demonstrated,enabling the homojunction phototransistors at zero bias to deliver a photoresponsivity of 311 mA W−1,a specific detectivity up to^10^11 Jones,and an on/off ratio up to^10^4.Remarkably,when illuminated by the lights ranging from 405 to 808 nm,the biased devices yield a champion photoresponsivity of 191.5 A W−1,a specific detectivity up to^1012 Jones,a photoconductive gain of 10^6–10^7,and a photoresponsive time in the order of^50 ms.These results provide a simple and competitive solution to the bandgap engineering of two-dimensional materials for device applications without the need for p–n junctions.展开更多
Mix-dimensional van der Waals heterostructures(vdWHs)have inspired worldwide interests and efforts in the field of ad-vanced electronics and optoelectronics.The fundamental understanding of interfacial charge transfer...Mix-dimensional van der Waals heterostructures(vdWHs)have inspired worldwide interests and efforts in the field of ad-vanced electronics and optoelectronics.The fundamental understanding of interfacial charge transfer is of vital import-ance for guiding the design of functional optoelectronic applications.In this work,type-Ⅱ0D-2D CdSe/ZnS quantum dots/MoS_(2)vdWHs are designed to study the light-triggered interfacial charge behaviors and enhanced optoelectronic performances.From spectral measurements in both steady and transient states,the phenomena of suppressed photolu-minescence(PL)emissions,shifted Raman signals and changed PL lifetimes provide strong evidences of efficient charge transfer at the 0D-2D interface.A series of spectral evolutions of heterostructures with various QDs overlapping concentrations at different laser powers are analyzed in details,which clarifies the dynamic competition between exciton and trion during an efficient doping of 3.9×10^(13)cm^(−2).The enhanced photoresponses(1.57×10^(4)A·W^(-1))and detectivities(2.86×10^(11)Jones)in 0D/2D phototransistors further demonstrate that the light-induced charge transfer is still a feasible way to optimize the performance of optoelectronic devices.These results are expected to inspire the basic understand-ing of interfacial physics at 0D/2D interfaces,and shed the light on promoting the development of mixed-dimensional op-toelectronic devices in the near future.展开更多
During the past decades,transition metal dichalcogenides(TMDs) have received special focus for their unique properties in photoelectric detection.As one important member of TMDs,MoS2 has been made into photodetector p...During the past decades,transition metal dichalcogenides(TMDs) have received special focus for their unique properties in photoelectric detection.As one important member of TMDs,MoS2 has been made into photodetector purely or combined with other materials,such as graphene,ionic liquid,and ferroelectric materials.Here,we report a gate-free MoS2 phototransistor combined with organic ferroelectric material poly(vinylidene fluoride-trifluoroethylene)(P(VDF-TrFE)).In this device,the remnant polarization field in P(VDF-TrFE) is obtained from the piezoelectric force microscope(PFM) probe with a positive or negative bias,which can turn the dipoles from disorder to be the same direction.Then,the MoS2 channel can be maintained at an accumulated state with downward polarization field modulation and a depleted state with upward polarization field modulation.Moreover,the P(VDF-TrFE) segregates MoS2 from oxygen and water molecules around surroundings,which enables a cleaner surface state.As a photodetector,an ultra-low dark current of 10^–11 A,on/off ration of more than 10^4 and a fast photoresponse time of 120 μs are achieved.This work provides a new method to make high-performance phototransistors assisted by the ferroelectric domain which can operate without a gate electrode and demonstrates great potential for ultra-low power consumption applications.展开更多
In this paper, the positive influence of a uni-traveling-carrier （UTC） structure to ease the contract between the respon- sivity and working speed of the InP-based double hetero-junction phototransistor （DHPT） is ...In this paper, the positive influence of a uni-traveling-carrier （UTC） structure to ease the contract between the respon- sivity and working speed of the InP-based double hetero-junction phototransistor （DHPT） is illustrated in detail. Different results under electrical bias, optical bias or combined electrical and optical bias are analyzed for an excellent UTC-DHPT performance. The results show that when the UTC-DHPT operates at three-terminal （3T） working mode with combined electrical bias and optical bias in base, it keeps a high optical responsivity of 34.72 A/W and the highest optical transition frequency of 120 GHz. The current gain of the 3T UTC-DHPT under 1.55-μm light illuminations reaches 62 dB. This indicates that the combined base electrical bias and optical bias of 3T UTC-DHPT can make sure that the UTC-DHPT provides high optical current gain and high optical transition frequency simultaneously.展开更多
Van der Waals heterostructures based on the two-dimensional(2D)semiconductor materials have attracted increasing attention due to their attractive properties.In this work,we demonstrate a high-sensitive back-gated pho...Van der Waals heterostructures based on the two-dimensional(2D)semiconductor materials have attracted increasing attention due to their attractive properties.In this work,we demonstrate a high-sensitive back-gated phototransistor based on the vertical HfSe_(2)/MoS_(2)heterostructure with a broad-spectral response from near-ultraviolet to near-infrared and an efficient gate tunability for photoresponse.Under bias,the phototransistor exhibits high responsivity of up to 1.42×103A/W,and ultrahigh specific detectivity of up to 1.39×1015cm·Hz^(1/2)·W^(-1).Moreover,it can also operate under zero bias with remarkable responsivity of 10.2 A/W,relatively high specific detectivity of 1.43×1014cm·Hz^(1/2)·W^(-1),ultralow dark current of 1.22 f A,and high on/off ratio of above 105.These results should be attributed to the fact that the vertical HfSe_(2)/MoS_(2)heterostructure not only improves the broadband photoresponse of the phototransistor but also greatly enhances its sensitivity.Therefore,the heterostructure provides a promising candidate for next generation high performance phototransistors.展开更多
In the field of organic phototransistor, achieving both broad-spectral and high photosensitivity has always been a big challenge. The innovation of device structure has previously proven to be a possible solution to t...In the field of organic phototransistor, achieving both broad-spectral and high photosensitivity has always been a big challenge. The innovation of device structure has previously proven to be a possible solution to this problem. Here in this study, a novel organic phototransistor based on a high mobility n-type small molecule as the conducting layer and an isolated bulk heterojunction light-absorbing layer as the floating gate has been demonstrated in this study. With the special designed device structure, the phototransistor shows extremely high sensitivity to broad spectral and weak light irradiation, and the photoresponsivity and photocurrent/dark-current ratio of the device can reach up to 4840 mA/W and 1.8×10~5 respectively.For conclusion, this study suggests a potential way to obtain high-performance phototransistors at room temperature, which will further promote the commercial application of organic phototransistors.展开更多
The development of high-performance neuromorphic phototransistors is of paramount importance for image perception and depth memory learning.Here,based on metal-oxide heterojunction architecture,artificial synaptic pho...The development of high-performance neuromorphic phototransistors is of paramount importance for image perception and depth memory learning.Here,based on metal-oxide heterojunction architecture,artificial synaptic phototransistors with synaptic plasticity have been achieved,demonstrating an artificial synapse that integrates central and optic nerve functions.Thanks to the sensitive light-detection properties,the optical power consumption of such photonic artificial synapses can be as low as 22 picojoules,which is extremely competitive compared with other pure metal oxide photoelectric synapses ever reported.What is more,owing to its good short-term(STP)and tunable amplitude-frequency characteristics,the as-constructed device can function as a biomimetic high-pass filter for picture edge detection.Dual-mode synaptic modulation has been performed,combining photonic pulse with gate voltage stimulus.After photoelectric-synergistic modulation,the high synaptic weights enable the device to simulate complex neural learning rules for neuromorphic applications,including gesture recognition,image perception in the visual system,and classically conditioned reflexes.These results suggest that the current oxide-based heterojunction architecture displays potential application in future multifunction neuromorphic devices and systems.展开更多
We report intrinsic photoconductivity studies on one of the least examined layered compounds,ZrS2.Few-atomic layer ZrS2 field-effect transistors were fabricated on the Si/SiO2 substrate and photoconductivity measureme...We report intrinsic photoconductivity studies on one of the least examined layered compounds,ZrS2.Few-atomic layer ZrS2 field-effect transistors were fabricated on the Si/SiO2 substrate and photoconductivity measurements were performed using both two-and four-terminal configurations under the illumination of 532 nm laser source.We measured photocurrent as a function of the incident optical power at several source-drain(bias)voltages.We observe a significantly large photoconductivity when measured in the multiterminal(four-terminal)configuration compared to that in the two-terminal configuration.For an incident optical power of 90 nW,the estimated photosensitivity and the external quantum efficiency(EQE)measured in two-terminal configuration are 0.5 A/W and 120%,respectively,under a bias voltage of 650 mV.Under the same conditions,the four-terminal measurements result in much higher values for both the photoresponsivity(R)and EQE to 6 A/W and 1400%,respectively.This significant improvement in photoresponsivity and EQE in the four-terminal configuration may have been influenced by the reduction of contact resistance at the metal-semiconductor interface,which greatly impacts the carrier mobility of low conducting materials.This suggests that photoconductivity measurements performed through the two-terminal configuration in previous studies on ZrS2 and other 2D materials have severely underestimated the true intrinsic properties of transition metal dichalcogenides and their remarkable potential for optoelectronic applications.展开更多
Determining the number of photons in an incident light pulse at room temperature is the ultimate goal of photodetection.Herein,we report a plasmon-strain-coupled tens of photon level phototransistor by integrating mon...Determining the number of photons in an incident light pulse at room temperature is the ultimate goal of photodetection.Herein,we report a plasmon-strain-coupled tens of photon level phototransistor by integrating monolayer MoS_(2)on top of Au nanowire(NW).Within this structure,Au NW can greatly enhance incident light intensity around MoS_(2),and the large tensile strain can reduce the contact energy barrier between MoS_(2)and Au NW,so as to achieve efficient injection of plasmonic hot electrons into MoS_(2).Furthermore,ultrashort MoS_(2)channel significantly shortens the carrier transit time.As a result,the phototransistor with record optical gain(3.1×10^(11))can accurately determine Poissonian emission statistics of light source with tens of photon level resolution at room temperature.In addition,the phototransistor also demonstrates a broadband spectral sensitivity(0.37–1.55μm),as well as intrinsic photon-polarization selection.Furthermore,an ultra-sensitive optical immunoassay(USOIA)platform is proposed using the phototransistor as photodetector.Coupled with specific antibody-conjugated quantum dot nanospheres and magnetic beads,the platform is able to detect the model biomarker,C-reactive protein,as low as 1.684 amol/L in serum samples with a dynamic range spanning 12 orders of magnitude.With its significantly enhanced sensitivity and simplicity,ultra-high-gain MoS_(2)phototransistor can pave the way toward optically ultra-sensitive determination of various biomarkers for early disease diagnosis.展开更多
In this work,a short-wave infrared(SWIR)n-MoSe_(2)/p-GeSn/n-germanium-on-insulator(GOI)heterojunction phototransistor(HPT)with Sn composition-graded GeSn base is proposed for improvement of overall performance at low ...In this work,a short-wave infrared(SWIR)n-MoSe_(2)/p-GeSn/n-germanium-on-insulator(GOI)heterojunction phototransistor(HPT)with Sn composition-graded GeSn base is proposed for improvement of overall performance at low cost.The Sn composition-graded GeSn base layers are grown using magnetron sputtering epitaxy technique for improvement of crystal quality with a high Sn content of 15.2%in the top layer,rendering the extension of the cutoff wavelength beyond 2400 nm and significant suppression of dark current.The enormous electron/hole injection ratio,resulting from the large bandgap offset between the MoSe_(2)emitter and the GeSn base,enables the harvesting of a high photocurrent gain of HPT.By optimizing the device parameters,a considerable responsivity of 23.79 A/W and an excellent specific detectivity of 8.24×10^(10)Jones at the peak wavelength of 2030 nm were achieved for the HPT with the dark current density of 261 mA/cm^(2)under the emitter-collector bias voltage of 1.0 V at room temperature.The fast response speed is obtained for the HPT in terms of rising/falling times of 2.8μs/9.3μs at 1550 nm,surpassing those of most van der Waals(vdW)junction-based devices.Those results demonstrate that GeSn HPTs are suitable for SWIR optoelectronic imaging and microwave photonics applications.展开更多
Wavelength selective imaging has a wide range of applications in image recognition and other application scenarios,which can effectively improve the recognition rate of objects.However,in the existing technical scenar...Wavelength selective imaging has a wide range of applications in image recognition and other application scenarios,which can effectively improve the recognition rate of objects.However,in the existing technical scenarios,it is usually necessary to use complex optical devices such as filters or gratings to achieve wavelength extraction.These methods inevitably bring about the problems of complex structure and low integration.Therefore,it is necessary to realize the wavelength extraction function at the device level.Here,we realize the wavelength extraction function and wide-spectrum imaging function in the visible to infrared band based on a visible light absorber/floating gate storage layer/near-infrared(NIR)photogating layer configuration.Under infrared irradiation,the device exhibits negative photoresponse through the absorption of infrared light by the Ge substrate and the photogating effect,and realizes visible positive light response through the absorption of visible light by MoS2.Utilizing the memory function of the device,by cleverly changing the gate voltage pulse,the photoresponse state of the output voltage is effectively adjusted to achieve three imaging states:visible light response only,response to both visible and infrared light,and infrared light response only.Active selective imaging of the word“XDU”was achieved at 532 and 1550 nm wavelength.By using the photoresponse data of the device,the passive imaging of the topography of Xi'an,Shaanxi Province was obtained,which effectively improves the recognition rate of mountains and rivers.The proposed reconfigurable visible–infrared wavelength-selective imaging photodetector can effectively extract image information and improve the image recognition rate while ensuring a simple structure.The single-chip-based spectral separation imaging solution lays a good foundation for the further development of visible–infrared vision applications.展开更多
The surging demand and adoption of infrared photodetectors(IRPDs)in sectors of imaging,mobile,healthcare,automobiles,and optical communication are hindered by the prohibitive costs of traditional IRPD materials such a...The surging demand and adoption of infrared photodetectors(IRPDs)in sectors of imaging,mobile,healthcare,automobiles,and optical communication are hindered by the prohibitive costs of traditional IRPD materials such as InGaAs and HgCdTe.Quantum dots(QDs),especially lead chalcogenide(PbS)QDs,represent the next-generation lowbandgap semiconductors for near-infrared(NIR)detection due to their high optical absorption coefficient,tunable bandgap,low fabrication costs,and device compatibility.Innovative techniques such as ligand exchange processes have been proposed to boost the performance of PbS QDs photodetectors,mostly using short ligands like 1,2-ethanedithiol(EDT)and tetrabutylammonium iodide(TBAI).Our study explores the use of long-chain dithiol ligands to enhance the responsivity of PbS QDs/InGaZnO phototransistors.Long-chain dithiol ligands are found to suppress horizontal electron transport/leakage and electron trapping,which is beneficial for responsivity.Utilizing a novel ligand-exchange technique with 1,10-decanedithiol(DDT),we develop high-performance hybrid phototransistors with detectivity exceeding 10^(14) Jones.Based on these phototransistors,we demonstrate image communication through a NIR optical communication system.The long-ligand PbS QDs/InGaZnO hybrid phototransistor demonstrates significant potential for NIR low-dose imaging and optical communication,particularly in scenarios requiring the detection of weak light signals at low frequencies.展开更多
Low-dimensional(LD)halide perovskites have attracted considerable attention due to their distinctive structures and exceptional optoelectronic properties,including high absorption coefficients,extended charge carrier ...Low-dimensional(LD)halide perovskites have attracted considerable attention due to their distinctive structures and exceptional optoelectronic properties,including high absorption coefficients,extended charge carrier diffusion lengths,suppressed non-radiative recombination rates,and intense photoluminescence.A key advantage of LD perovskites is the tunability of their optical and electronic properties through the precise optimization of their structural arrangements and dimensionality.This review systematically examines recent progress in the synthesis and optoelectronic characterizations of LD perovskites,focusing on their structural,optical,and photophysical properties that underpin their versatility in diverse applications.The review further summarizes advancements in LD perovskite-based devices,including resistive memory,artificial synapses,photodetectors,light-emitting diodes,and solar cells.Finally,the challenges associated with stability,scalability,and integration,as well as future prospects,are discussed,emphasizing the potential of LD perovskites to drive breakthroughs in device efficiency and industrial applicability.展开更多
Two-dimensional （2D） layered transition metal dichalcogenides （TMDs） have attracted enormous research interests and efforts towards the development of versatile electronic and optical devices, owing to their extra...Two-dimensional （2D） layered transition metal dichalcogenides （TMDs） have attracted enormous research interests and efforts towards the development of versatile electronic and optical devices, owing to their extraordinary and unique fundamental properties and remarkable prospects in nanoelectronic applications. Among the TMDs, tungsten diselenide （WSe2） exhibits tunable ambipolar transport characteristics and superior optical properties such as high quantum efficiency. Herein, we demonstrate significant enhancement in the device performance of WSe2 phototransistor by in situ surface functionalization with cesium carbonate （Cs2CO3）. WSe2 was found to be strongly doped with electrons after Cs2CO3 modification. The electron mobility of WSe2 increased by almost one order of magnitude after surface functionalization with 1.6-nm-thick Cs2CO3 decoration. Furthermore, the photocurrent of the WSe2-based phototransistor increased by nearly three orders of magnitude with the deposition of 1.6-nm-thick Cs2CO3. Characterizations by in situ photoelectron spectroscopy techniques confirmed the significant surface charge transfer occurring at the Cs2COB/WSe2 interface. Our findings coupled with the tunable nature of the surface transfer doping method establish WSe2 as a promising candidate for future 2D materials- based optoelectronic devices.展开更多
Molybdenum ditelluride （MoTe2） has been demonstrated great potential in electronic and optoelectronic applications. However, the reported effective hole mobility remains far below its theoretical value. Herein, taki...Molybdenum ditelluride （MoTe2） has been demonstrated great potential in electronic and optoelectronic applications. However, the reported effective hole mobility remains far below its theoretical value. Herein, taking advantage of high-κ screening effect, we have fabricated back-gated MoTe2 transistors on an Al2O3 high-κ dielectric and systematically investigated the electronic and optoelectronic proper- ties. A high current on/off ratio exceeding 106 is achieved in the Al2O3-based MoTe2 transistors, and the hole mobility is demonstrated to be 150 cm2 V^-1 s^-1, compared to 0.2-20 cm^2 V^-1 s^-1 ever obtained from back-gated MoTe2 transistors in the literatures. Moreover, a considerable hole concentration of 1.2 × 10^13 cm 2 is attained in our Al2O3-based MoTe2 transistors owing to the strong gate control capa- bility, leading to a high on-state hole current of 6.1 μA μm^-1. After optimization, our Al2O3-based MoTe2 phototransistor exhibits outstanding photodetective performance, with a high responsivity of 543 AW^-1 and a high photogain of 1,662 at 405 nm light illumination, which are boosted around 419 times compared to the referential SiO2-based control devices. The mechanisms of photoconductivity in the Al2O3-based MoTe2 phototransistors have been analyzed in detail, and the photogating effect is considered to play an important role. This work may provide useful insight to improve carrier mobility in two-dimensional layered semiconductors and open opportunities to facilitate the development of high-performance photodetectors in the future.展开更多
The com bination of mixed-dimensional semiconducti ng materials can provide additional freedom to construct integrated n anoscale electronic and optoelectronic devices with diverse functionalities. In this work, we re...The com bination of mixed-dimensional semiconducti ng materials can provide additional freedom to construct integrated n anoscale electronic and optoelectronic devices with diverse functionalities. In this work, we report a high-performanee dual-channel phototransistor based on one-dimensional (1D)/two-dimensional (2D) trigonal selenium (t-Se)/ReS2 heterostructures grown by chemical vapor deposition. The injection and separati on efficie ncy of photoge nerated electro n-hole pairs can be greatly improved due to the high-quality in terfacial con tact betwee n t-Se nano belts and ReS2 films. Compared with bare ReS2 film devices, the dual-cha nnel phototra nsistor based on t-Se/ReS2 heterostructure exhibits considerable enhancement with the responsivity (R) and detectivity (D^*) up to 98 A·W^-1 and 6 x 10^10 Jones at 400 nm illumination with an in tensity of 1.7 mW·cm^-2, respectively. Besides, the respo nse time can also be reduced by three times of magnitude to less than 50 ms due to the type-11 band alignment at the in terface. This study opens up a promising ave nue for high-performa nee photodetectors by constructing mixed-dimensional heterostructures.展开更多
Two-dimensional(2D)layered materials have attracted extensive research interest in the field of high-performance photodetection due to their high carrier mobility,tunable bandgap,stability,other excellent properties.H...Two-dimensional(2D)layered materials have attracted extensive research interest in the field of high-performance photodetection due to their high carrier mobility,tunable bandgap,stability,other excellent properties.Herein,we propose a gate-tunable,high-performance,self-driving,wide detection range phototransistor based on a 2D PtSe_(2)on silicon-oninsulator(SOI).Benefiting from the strong built-in electric field of the PtSe_(2)/Si heterostructure,the phototransistor has a fast response time(rise/fall time)of 36.7/32.6μs.The PtSe_(2)/Si phototransistor exhibits excellent photodetection performance over a broad spectral range from ultraviolet to near-infrared,including a responsivity of 1.07 A/W and a specific detectivity of 6.60×10^(9)Jones under 808 nm illumination at zero gate voltage.The responsivity and specific detectivity of PtSe_(2)/Si phototransistor at 5 V gate voltage are increased to 13.85 A/W and 1.90×10^(10) Jones under 808 nm illumination.Furthermore,the fabricated PtSe_(2)/Si phototransistor array shows excellent uniformity,reproducibility,long-term stability in terms of photoresponse performance with negligible variation between pixel cells.The architecture of present PtSe_(2)/Si on SOI platform paves a new way of a general strategy to realize high-performance photodetectors by combining the advantages of both 2D materials and conventional semiconductors which is compatible with current Si-complementary metal oxide semiconductor(CMOS)process.展开更多
Organic phototransistors based on high-quality 2,8-dichloro-5,11-dihexyl-indolo[3,2-b]carbazo(CHICZ)single crystals show the highest photoresponsivity of 3×10^3 A W^-1, photosensitivity of 2×10^4 and the det...Organic phototransistors based on high-quality 2,8-dichloro-5,11-dihexyl-indolo[3,2-b]carbazo(CHICZ)single crystals show the highest photoresponsivity of 3×10^3 A W^-1, photosensitivity of 2×10^4 and the detectivity can achieve 8.4×10^14 Jones. We also discovered good linear dependence of log(photosensitivity) versus the wavelength when the devices were illuminated with a series of sameintensity but different-wavelength lights. The organic phototransistors based on CHICZ single crystal have potential applications in wavelength-detection.展开更多
Near-infrared organic phototransistors have wide application prospects in many fields.The active materials with the high mobility and near-infrared response are critical to building high-performance near-infrared orga...Near-infrared organic phototransistors have wide application prospects in many fields.The active materials with the high mobility and near-infrared response are critical to building high-performance near-infrared organic phototransistors,which are scarce at present.Herein,a new charge transfer cocrystal using 5,7-dihydroindolo[2,3-b]carbazole(5,7-ICZ)as the donor and 2,2’-(benzo[1,2-b:4,5-b’]dithiophene-4,8-diylidene)dimalononitrile(DTTCNQ)as the acceptor is properly designed and prepared in a stoichiometric ratio(D:A=1:1),which not only displays a high electron mobility of 0.15 cm^(2)V^(-1)s^(-1) and very low dark current,but also can serve as the active layer materials in the region of near-infrared detection due to the narrowed band gap and good charge transport properties.A high photosensitivity of 1.8×10^(4),the ultrahigh photoresponsivity of 2,923 A W-1and the high detectivity of 4.26×10^(11)Jones of the organic near-infrared phototransistors are obtained.展开更多
文摘The fabrication and characterization of a Schottky-emitter heterojunction-collector UV-enhanced bipolar phototransistor （SHBT） are presented. The luminescence peak of the ZnO film is observed at 371nm in the PL spectrum. The sensitivity of the ultraviolet response from 200 to 400nm is enhanced noticeably, and the spectrum response at wavelengths longer than 400nm is also retained, The experiments show that the Au/n-ZnO/p-Si SHBT UV enhanced phototransistor enhances the sensitivity of the ultraviolet response noticeably. The UV response sensitivity at 370nm of the phototransistor is 5-10 times that of a ZnO/Si heterojunction UV enhanced photodiode.
基金supported by Grants from the UK EPSRC Future Compound Semiconductor Manufacturing Hub(EP/P006973/1)the financial support from EPSRC(EP/L018330/1,EP/N032888/1)+3 种基金the U.S.Army Research Laboratory under Cooperative Agreement Number W911NF-16-2-0120the “973 Program—the National Basic Research Program of China” Special Funds for the Chief Young Scientis(2015CB358600)the Excellent Young Scholar Fund from National Natural Science Foundation of China(21422103)the China Scholarship Council(CSC)
文摘Ternary transition metal dichalcogenide alloys with spatially graded bandgaps are an emerging class of two-dimensional materials with unique features,which opens up new potential for device applications.Here,visible–near-infrared and self-powered phototransistors based on spatially bandgap-graded MoS2(1−x)Se2x alloys,synthesized by a simple and controllable chemical solution deposition method,are reported.The graded bandgaps,arising from the spatial grading of Se composition and thickness within a single domain,are tuned from 1.83 to 1.73 eV,leading to the formation of a homojunction with a builtin electric field.Consequently,a strong and sensitive gate-modulated photovoltaic effect is demonstrated,enabling the homojunction phototransistors at zero bias to deliver a photoresponsivity of 311 mA W−1,a specific detectivity up to^10^11 Jones,and an on/off ratio up to^10^4.Remarkably,when illuminated by the lights ranging from 405 to 808 nm,the biased devices yield a champion photoresponsivity of 191.5 A W−1,a specific detectivity up to^1012 Jones,a photoconductive gain of 10^6–10^7,and a photoresponsive time in the order of^50 ms.These results provide a simple and competitive solution to the bandgap engineering of two-dimensional materials for device applications without the need for p–n junctions.
基金This work is supported by National Natural Science Foundation of China(No.92163135,11904098,51972105,U19A2090 and 62090035)Hunan Provincial Natural Science Foundation of China(No.2019JJ30004)+1 种基金Hunan International Innovation Cooperation Platform(No.2018WK4004)Key Program of Science and Technology Department of Hunan Province(Nos.2019XK2001,2020XK2001).
文摘Mix-dimensional van der Waals heterostructures(vdWHs)have inspired worldwide interests and efforts in the field of ad-vanced electronics and optoelectronics.The fundamental understanding of interfacial charge transfer is of vital import-ance for guiding the design of functional optoelectronic applications.In this work,type-Ⅱ0D-2D CdSe/ZnS quantum dots/MoS_(2)vdWHs are designed to study the light-triggered interfacial charge behaviors and enhanced optoelectronic performances.From spectral measurements in both steady and transient states,the phenomena of suppressed photolu-minescence(PL)emissions,shifted Raman signals and changed PL lifetimes provide strong evidences of efficient charge transfer at the 0D-2D interface.A series of spectral evolutions of heterostructures with various QDs overlapping concentrations at different laser powers are analyzed in details,which clarifies the dynamic competition between exciton and trion during an efficient doping of 3.9×10^(13)cm^(−2).The enhanced photoresponses(1.57×10^(4)A·W^(-1))and detectivities(2.86×10^(11)Jones)in 0D/2D phototransistors further demonstrate that the light-induced charge transfer is still a feasible way to optimize the performance of optoelectronic devices.These results are expected to inspire the basic understand-ing of interfacial physics at 0D/2D interfaces,and shed the light on promoting the development of mixed-dimensional op-toelectronic devices in the near future.
基金supported by the Major State Basic Research Development Program (Grant Nos. 2016YFA0203900, 2016YFB0400801 and 2015CB921600)Key Research Project of Frontier Sciences of Chinese Academy of Sciences (Nos. QYZDB-SSW-JSC016, QYZDY-SSW-JSC042)+2 种基金Strategic Priority Research Program of Chinese Academy of Sciences (XDPB12, XDB 3000000)Natural Science Foundation of China (Grant Nos. 61521001, 61574151, 61574152, 61674158, 61722408, 61734003 and 61835012)Natural Science Foundation of Shanghai (Grant No. 16ZR1447600, 17JC1400302)
文摘During the past decades,transition metal dichalcogenides(TMDs) have received special focus for their unique properties in photoelectric detection.As one important member of TMDs,MoS2 has been made into photodetector purely or combined with other materials,such as graphene,ionic liquid,and ferroelectric materials.Here,we report a gate-free MoS2 phototransistor combined with organic ferroelectric material poly(vinylidene fluoride-trifluoroethylene)(P(VDF-TrFE)).In this device,the remnant polarization field in P(VDF-TrFE) is obtained from the piezoelectric force microscope(PFM) probe with a positive or negative bias,which can turn the dipoles from disorder to be the same direction.Then,the MoS2 channel can be maintained at an accumulated state with downward polarization field modulation and a depleted state with upward polarization field modulation.Moreover,the P(VDF-TrFE) segregates MoS2 from oxygen and water molecules around surroundings,which enables a cleaner surface state.As a photodetector,an ultra-low dark current of 10^–11 A,on/off ration of more than 10^4 and a fast photoresponse time of 120 μs are achieved.This work provides a new method to make high-performance phototransistors assisted by the ferroelectric domain which can operate without a gate electrode and demonstrates great potential for ultra-low power consumption applications.
基金Project supported by the National Natural Science Foundation of China(Grant No.61006044)the Natural Science Foundation of Beijing,China(Grant Nos.4122014 and 4142007)the Fund from the Beijing Municipal Education Committee,China(Grant No.KM200910005001)
文摘In this paper, the positive influence of a uni-traveling-carrier （UTC） structure to ease the contract between the respon- sivity and working speed of the InP-based double hetero-junction phototransistor （DHPT） is illustrated in detail. Different results under electrical bias, optical bias or combined electrical and optical bias are analyzed for an excellent UTC-DHPT performance. The results show that when the UTC-DHPT operates at three-terminal （3T） working mode with combined electrical bias and optical bias in base, it keeps a high optical responsivity of 34.72 A/W and the highest optical transition frequency of 120 GHz. The current gain of the 3T UTC-DHPT under 1.55-μm light illuminations reaches 62 dB. This indicates that the combined base electrical bias and optical bias of 3T UTC-DHPT can make sure that the UTC-DHPT provides high optical current gain and high optical transition frequency simultaneously.
基金Project supported by the National Natural Science Foundation of China(Grant No.51702245)the Fundamental Research Funds for the Central Universities(Grant No.WUT2021III065JC)
文摘Van der Waals heterostructures based on the two-dimensional(2D)semiconductor materials have attracted increasing attention due to their attractive properties.In this work,we demonstrate a high-sensitive back-gated phototransistor based on the vertical HfSe_(2)/MoS_(2)heterostructure with a broad-spectral response from near-ultraviolet to near-infrared and an efficient gate tunability for photoresponse.Under bias,the phototransistor exhibits high responsivity of up to 1.42×103A/W,and ultrahigh specific detectivity of up to 1.39×1015cm·Hz^(1/2)·W^(-1).Moreover,it can also operate under zero bias with remarkable responsivity of 10.2 A/W,relatively high specific detectivity of 1.43×1014cm·Hz^(1/2)·W^(-1),ultralow dark current of 1.22 f A,and high on/off ratio of above 105.These results should be attributed to the fact that the vertical HfSe_(2)/MoS_(2)heterostructure not only improves the broadband photoresponse of the phototransistor but also greatly enhances its sensitivity.Therefore,the heterostructure provides a promising candidate for next generation high performance phototransistors.
基金supported financially by the Ministry of Science and Technology of the People's Republic of China(No.2017YFA0206600)the National Natural Science Foundation of China(Nos.52050171,51822301,22175047,52103203,and 91963126)+4 种基金the CAS Instrument Development Project(No.YJKYYQ20170037)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB36020000)the CAS Pioneer Hundred Talents Programthe Natural Science Foundation of Shandong Province(No.ZR2020ME070)China Postdoctoral Science Foundation(No.2021M690802)。
文摘In the field of organic phototransistor, achieving both broad-spectral and high photosensitivity has always been a big challenge. The innovation of device structure has previously proven to be a possible solution to this problem. Here in this study, a novel organic phototransistor based on a high mobility n-type small molecule as the conducting layer and an isolated bulk heterojunction light-absorbing layer as the floating gate has been demonstrated in this study. With the special designed device structure, the phototransistor shows extremely high sensitivity to broad spectral and weak light irradiation, and the photoresponsivity and photocurrent/dark-current ratio of the device can reach up to 4840 mA/W and 1.8×10~5 respectively.For conclusion, this study suggests a potential way to obtain high-performance phototransistors at room temperature, which will further promote the commercial application of organic phototransistors.
基金supported by the National Natural Science Foun-dation of China(Nos.11774001,52202156,52103297)the Anhui Project(No.Z010118169)+2 种基金the Scientific research project of colleges and universities in Anhui Province(No.2022AH050113)the Uni-versity Synergy Innovation Program of Anhui Province(No.GXXT-2022-012)the Postdoctoral daily public start-up funds of An-hui University(No.S202418001/069).
文摘The development of high-performance neuromorphic phototransistors is of paramount importance for image perception and depth memory learning.Here,based on metal-oxide heterojunction architecture,artificial synaptic phototransistors with synaptic plasticity have been achieved,demonstrating an artificial synapse that integrates central and optic nerve functions.Thanks to the sensitive light-detection properties,the optical power consumption of such photonic artificial synapses can be as low as 22 picojoules,which is extremely competitive compared with other pure metal oxide photoelectric synapses ever reported.What is more,owing to its good short-term(STP)and tunable amplitude-frequency characteristics,the as-constructed device can function as a biomimetic high-pass filter for picture edge detection.Dual-mode synaptic modulation has been performed,combining photonic pulse with gate voltage stimulus.After photoelectric-synergistic modulation,the high synaptic weights enable the device to simulate complex neural learning rules for neuromorphic applications,including gesture recognition,image perception in the visual system,and classically conditioned reflexes.These results suggest that the current oxide-based heterojunction architecture displays potential application in future multifunction neuromorphic devices and systems.
基金N.R.P.acknowledged NSF-PREM through NSFDMR-1826886,HBCU-UP Excellence in research NSFDMR-1900692A portion of this work was performed at the National High Magnetic Field Laboratory,which is supported by the National Science Foundation Cooperative Agreement No.DMR-1644779+1 种基金the State of Florida.This work was performed,in part,at the Center for Nanoscale Materials,a U.S.Department of Energy Office of Science User Facilitysupported by the U.S.Department of Energy,Office of Science,under Contract No.DE-AC02-06CH11357.
文摘We report intrinsic photoconductivity studies on one of the least examined layered compounds,ZrS2.Few-atomic layer ZrS2 field-effect transistors were fabricated on the Si/SiO2 substrate and photoconductivity measurements were performed using both two-and four-terminal configurations under the illumination of 532 nm laser source.We measured photocurrent as a function of the incident optical power at several source-drain(bias)voltages.We observe a significantly large photoconductivity when measured in the multiterminal(four-terminal)configuration compared to that in the two-terminal configuration.For an incident optical power of 90 nW,the estimated photosensitivity and the external quantum efficiency(EQE)measured in two-terminal configuration are 0.5 A/W and 120%,respectively,under a bias voltage of 650 mV.Under the same conditions,the four-terminal measurements result in much higher values for both the photoresponsivity(R)and EQE to 6 A/W and 1400%,respectively.This significant improvement in photoresponsivity and EQE in the four-terminal configuration may have been influenced by the reduction of contact resistance at the metal-semiconductor interface,which greatly impacts the carrier mobility of low conducting materials.This suggests that photoconductivity measurements performed through the two-terminal configuration in previous studies on ZrS2 and other 2D materials have severely underestimated the true intrinsic properties of transition metal dichalcogenides and their remarkable potential for optoelectronic applications.
基金supported by the National Key Research and Development Program of the Ministry of Science and Technology(2023YFA0915602)the Creative Research Groups Program of the National Natural Science Foundation of China(62321003)+8 种基金the National Natural Science Foundation of China(62134001,U24A20302,62134001,12174094,62274060,62311540157,32271519,and 62274059)the Natural Science Foundation of Hunan Province(2021RC5004)the Science and Technology Innovation Program of Hunan Province(2023RC3112)the Key Research and Development Plan of Hunan Province(2025WK2013)the Guangdong Basic and Applied Basic Research Foundation(2022B1515020029,2022ZDZX2074,and 2024A1515012157)the Shenzhen Science andTechnology Research Funding(JSGG20201103153801005,JCYJ20220818101413029,and ZDSYS20220527171406014)the Shenzhen Medical Research Fund(B2302028)the Key Laboratory of Biomedical Imaging Science and System,Chinese Academy of Sciences,the Key Laboratory of Nanodevices of Jiangsu Province(ZF2302)the Changsha Municipal Natural Science Foundation(kq2402050).
文摘Determining the number of photons in an incident light pulse at room temperature is the ultimate goal of photodetection.Herein,we report a plasmon-strain-coupled tens of photon level phototransistor by integrating monolayer MoS_(2)on top of Au nanowire(NW).Within this structure,Au NW can greatly enhance incident light intensity around MoS_(2),and the large tensile strain can reduce the contact energy barrier between MoS_(2)and Au NW,so as to achieve efficient injection of plasmonic hot electrons into MoS_(2).Furthermore,ultrashort MoS_(2)channel significantly shortens the carrier transit time.As a result,the phototransistor with record optical gain(3.1×10^(11))can accurately determine Poissonian emission statistics of light source with tens of photon level resolution at room temperature.In addition,the phototransistor also demonstrates a broadband spectral sensitivity(0.37–1.55μm),as well as intrinsic photon-polarization selection.Furthermore,an ultra-sensitive optical immunoassay(USOIA)platform is proposed using the phototransistor as photodetector.Coupled with specific antibody-conjugated quantum dot nanospheres and magnetic beads,the platform is able to detect the model biomarker,C-reactive protein,as low as 1.684 amol/L in serum samples with a dynamic range spanning 12 orders of magnitude.With its significantly enhanced sensitivity and simplicity,ultra-high-gain MoS_(2)phototransistor can pave the way toward optically ultra-sensitive determination of various biomarkers for early disease diagnosis.
基金supported in part by the National Natural Science Foundation of China(Nos.62074134 and 62104205)in part by the National Key Research and Development Program of China(No.2018YFB2200103).
文摘In this work,a short-wave infrared(SWIR)n-MoSe_(2)/p-GeSn/n-germanium-on-insulator(GOI)heterojunction phototransistor(HPT)with Sn composition-graded GeSn base is proposed for improvement of overall performance at low cost.The Sn composition-graded GeSn base layers are grown using magnetron sputtering epitaxy technique for improvement of crystal quality with a high Sn content of 15.2%in the top layer,rendering the extension of the cutoff wavelength beyond 2400 nm and significant suppression of dark current.The enormous electron/hole injection ratio,resulting from the large bandgap offset between the MoSe_(2)emitter and the GeSn base,enables the harvesting of a high photocurrent gain of HPT.By optimizing the device parameters,a considerable responsivity of 23.79 A/W and an excellent specific detectivity of 8.24×10^(10)Jones at the peak wavelength of 2030 nm were achieved for the HPT with the dark current density of 261 mA/cm^(2)under the emitter-collector bias voltage of 1.0 V at room temperature.The fast response speed is obtained for the HPT in terms of rising/falling times of 2.8μs/9.3μs at 1550 nm,surpassing those of most van der Waals(vdW)junction-based devices.Those results demonstrate that GeSn HPTs are suitable for SWIR optoelectronic imaging and microwave photonics applications.
基金National Natural Science Foundation of China,Grant/Award Numbers:62374129,62134005,62204188National Key Research and Development Program of China,Grant/Award Number:2023YFB2805000。
文摘Wavelength selective imaging has a wide range of applications in image recognition and other application scenarios,which can effectively improve the recognition rate of objects.However,in the existing technical scenarios,it is usually necessary to use complex optical devices such as filters or gratings to achieve wavelength extraction.These methods inevitably bring about the problems of complex structure and low integration.Therefore,it is necessary to realize the wavelength extraction function at the device level.Here,we realize the wavelength extraction function and wide-spectrum imaging function in the visible to infrared band based on a visible light absorber/floating gate storage layer/near-infrared(NIR)photogating layer configuration.Under infrared irradiation,the device exhibits negative photoresponse through the absorption of infrared light by the Ge substrate and the photogating effect,and realizes visible positive light response through the absorption of visible light by MoS2.Utilizing the memory function of the device,by cleverly changing the gate voltage pulse,the photoresponse state of the output voltage is effectively adjusted to achieve three imaging states:visible light response only,response to both visible and infrared light,and infrared light response only.Active selective imaging of the word“XDU”was achieved at 532 and 1550 nm wavelength.By using the photoresponse data of the device,the passive imaging of the topography of Xi'an,Shaanxi Province was obtained,which effectively improves the recognition rate of mountains and rivers.The proposed reconfigurable visible–infrared wavelength-selective imaging photodetector can effectively extract image information and improve the image recognition rate while ensuring a simple structure.The single-chip-based spectral separation imaging solution lays a good foundation for the further development of visible–infrared vision applications.
基金the EPSRC SWIMS(EP/V039717/1)Royal Society(RGS\R1\221009 and IEC\NSFC\211201)+4 种基金Leverhulme Trust(RPG-6062022-263)Sêr Cymru programme-Enhancing Competitiveness Equipment Awards 2022-23(MA/VG/2715/22-PN66)the financial support from National Natural Science Foundation of China(NSFC)Grant No.62105214the financial support from National Natural Science Foundation of China(NSFC)No.61974006Shenzhen Science and Technology Innovation Committee(KJZD20230923113759002 and GJHZ20240218113959009).
文摘The surging demand and adoption of infrared photodetectors(IRPDs)in sectors of imaging,mobile,healthcare,automobiles,and optical communication are hindered by the prohibitive costs of traditional IRPD materials such as InGaAs and HgCdTe.Quantum dots(QDs),especially lead chalcogenide(PbS)QDs,represent the next-generation lowbandgap semiconductors for near-infrared(NIR)detection due to their high optical absorption coefficient,tunable bandgap,low fabrication costs,and device compatibility.Innovative techniques such as ligand exchange processes have been proposed to boost the performance of PbS QDs photodetectors,mostly using short ligands like 1,2-ethanedithiol(EDT)and tetrabutylammonium iodide(TBAI).Our study explores the use of long-chain dithiol ligands to enhance the responsivity of PbS QDs/InGaZnO phototransistors.Long-chain dithiol ligands are found to suppress horizontal electron transport/leakage and electron trapping,which is beneficial for responsivity.Utilizing a novel ligand-exchange technique with 1,10-decanedithiol(DDT),we develop high-performance hybrid phototransistors with detectivity exceeding 10^(14) Jones.Based on these phototransistors,we demonstrate image communication through a NIR optical communication system.The long-ligand PbS QDs/InGaZnO hybrid phototransistor demonstrates significant potential for NIR low-dose imaging and optical communication,particularly in scenarios requiring the detection of weak light signals at low frequencies.
基金funding from FCT(Fundagao para a Ciencia e Tecnologia,I.P.)under the projects LA/P/0037/2020,UIDP/50025/2020 and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures,Nanomodelling and Nanofabrication-i3Nby the projects FlexSolar(PTDC/CTM-REF/1008/2020),and SpaceFlex(2022.01610.PTDC,DOI:10.54499/2022.01610.PTDC)+1 种基金supported by the project M-ECO2-Industrial Cluster for advanced biofuel production,Ref.C644930471-00000041,R2U Technologies and Befunding from the European Union via the project X-STREAM(Horizon EU,ERC CoG,No 101124803)the support of a fellowship from the"la Caixa"Foundation(ID 100010434)。
文摘Low-dimensional(LD)halide perovskites have attracted considerable attention due to their distinctive structures and exceptional optoelectronic properties,including high absorption coefficients,extended charge carrier diffusion lengths,suppressed non-radiative recombination rates,and intense photoluminescence.A key advantage of LD perovskites is the tunability of their optical and electronic properties through the precise optimization of their structural arrangements and dimensionality.This review systematically examines recent progress in the synthesis and optoelectronic characterizations of LD perovskites,focusing on their structural,optical,and photophysical properties that underpin their versatility in diverse applications.The review further summarizes advancements in LD perovskite-based devices,including resistive memory,artificial synapses,photodetectors,light-emitting diodes,and solar cells.Finally,the challenges associated with stability,scalability,and integration,as well as future prospects,are discussed,emphasizing the potential of LD perovskites to drive breakthroughs in device efficiency and industrial applicability.
基金Acknowledgements W. C. acknowledges the financial support from Singapore MOE Grant R143-000-652-112, National Natural Science Foundation of China （No. 21573156） and the technical support from Centre for Advanced 2D Materials and Graphene Research Centre for the device fabrication. G. E. acknowledges Singapore National Research Foundation, Prime Minister＇s Office, Singapore, for funding the research under its Medium-sized Centre program as well as NRF Research Fellowship （No. NRF-NRFF2011-02）. G. E. also acknowledges financial support from Singapore MOE （No. MOE2015-T2-2-123）.
文摘Two-dimensional （2D） layered transition metal dichalcogenides （TMDs） have attracted enormous research interests and efforts towards the development of versatile electronic and optical devices, owing to their extraordinary and unique fundamental properties and remarkable prospects in nanoelectronic applications. Among the TMDs, tungsten diselenide （WSe2） exhibits tunable ambipolar transport characteristics and superior optical properties such as high quantum efficiency. Herein, we demonstrate significant enhancement in the device performance of WSe2 phototransistor by in situ surface functionalization with cesium carbonate （Cs2CO3）. WSe2 was found to be strongly doped with electrons after Cs2CO3 modification. The electron mobility of WSe2 increased by almost one order of magnitude after surface functionalization with 1.6-nm-thick Cs2CO3 decoration. Furthermore, the photocurrent of the WSe2-based phototransistor increased by nearly three orders of magnitude with the deposition of 1.6-nm-thick Cs2CO3. Characterizations by in situ photoelectron spectroscopy techniques confirmed the significant surface charge transfer occurring at the Cs2COB/WSe2 interface. Our findings coupled with the tunable nature of the surface transfer doping method establish WSe2 as a promising candidate for future 2D materials- based optoelectronic devices.
基金supported by the National Key Research and Development Program of China(2016YFA0302300,016YFA0200400)the National Science and Technology Major Project of China(2016ZX02301001)+1 种基金the National Natural Science Foundation of China(61306105)the Tsinghua University Initiative Scientific Research Program
文摘Molybdenum ditelluride （MoTe2） has been demonstrated great potential in electronic and optoelectronic applications. However, the reported effective hole mobility remains far below its theoretical value. Herein, taking advantage of high-κ screening effect, we have fabricated back-gated MoTe2 transistors on an Al2O3 high-κ dielectric and systematically investigated the electronic and optoelectronic proper- ties. A high current on/off ratio exceeding 106 is achieved in the Al2O3-based MoTe2 transistors, and the hole mobility is demonstrated to be 150 cm2 V^-1 s^-1, compared to 0.2-20 cm^2 V^-1 s^-1 ever obtained from back-gated MoTe2 transistors in the literatures. Moreover, a considerable hole concentration of 1.2 × 10^13 cm 2 is attained in our Al2O3-based MoTe2 transistors owing to the strong gate control capa- bility, leading to a high on-state hole current of 6.1 μA μm^-1. After optimization, our Al2O3-based MoTe2 phototransistor exhibits outstanding photodetective performance, with a high responsivity of 543 AW^-1 and a high photogain of 1,662 at 405 nm light illumination, which are boosted around 419 times compared to the referential SiO2-based control devices. The mechanisms of photoconductivity in the Al2O3-based MoTe2 phototransistors have been analyzed in detail, and the photogating effect is considered to play an important role. This work may provide useful insight to improve carrier mobility in two-dimensional layered semiconductors and open opportunities to facilitate the development of high-performance photodetectors in the future.
基金National Natural Science Foundation of China (Nos. 51572057 and 51772064)AFOSR/NSF EFRI 2DARE program, ARO and SRC.
文摘The com bination of mixed-dimensional semiconducti ng materials can provide additional freedom to construct integrated n anoscale electronic and optoelectronic devices with diverse functionalities. In this work, we report a high-performanee dual-channel phototransistor based on one-dimensional (1D)/two-dimensional (2D) trigonal selenium (t-Se)/ReS2 heterostructures grown by chemical vapor deposition. The injection and separati on efficie ncy of photoge nerated electro n-hole pairs can be greatly improved due to the high-quality in terfacial con tact betwee n t-Se nano belts and ReS2 films. Compared with bare ReS2 film devices, the dual-cha nnel phototra nsistor based on t-Se/ReS2 heterostructure exhibits considerable enhancement with the responsivity (R) and detectivity (D^*) up to 98 A·W^-1 and 6 x 10^10 Jones at 400 nm illumination with an in tensity of 1.7 mW·cm^-2, respectively. Besides, the respo nse time can also be reduced by three times of magnitude to less than 50 ms due to the type-11 band alignment at the in terface. This study opens up a promising ave nue for high-performa nee photodetectors by constructing mixed-dimensional heterostructures.
基金the National Natural Science Foundation of China(Nos.62090030/62090031,51872257,51672244,and 62274145)the National Key R&D Program of China(No.2021YFA1200502)+1 种基金the Natural Science Foundation of Zhejiang Province(No.LZ20F040001)the Zhejiang Province Key R&D Pprogram(No.2020C01120).
文摘Two-dimensional(2D)layered materials have attracted extensive research interest in the field of high-performance photodetection due to their high carrier mobility,tunable bandgap,stability,other excellent properties.Herein,we propose a gate-tunable,high-performance,self-driving,wide detection range phototransistor based on a 2D PtSe_(2)on silicon-oninsulator(SOI).Benefiting from the strong built-in electric field of the PtSe_(2)/Si heterostructure,the phototransistor has a fast response time(rise/fall time)of 36.7/32.6μs.The PtSe_(2)/Si phototransistor exhibits excellent photodetection performance over a broad spectral range from ultraviolet to near-infrared,including a responsivity of 1.07 A/W and a specific detectivity of 6.60×10^(9)Jones under 808 nm illumination at zero gate voltage.The responsivity and specific detectivity of PtSe_(2)/Si phototransistor at 5 V gate voltage are increased to 13.85 A/W and 1.90×10^(10) Jones under 808 nm illumination.Furthermore,the fabricated PtSe_(2)/Si phototransistor array shows excellent uniformity,reproducibility,long-term stability in terms of photoresponse performance with negligible variation between pixel cells.The architecture of present PtSe_(2)/Si on SOI platform paves a new way of a general strategy to realize high-performance photodetectors by combining the advantages of both 2D materials and conventional semiconductors which is compatible with current Si-complementary metal oxide semiconductor(CMOS)process.
基金financial support from the Ministry of Science and Technology of China (2017YFA0204503 and 2016YFB0401100)the National Natural Science Foundation of China (51725304, 51633006, 51703159 and 51733004)the Strategic Priority Research Program (XDB12030300) of the Chinese Academy of Sciences
文摘Organic phototransistors based on high-quality 2,8-dichloro-5,11-dihexyl-indolo[3,2-b]carbazo(CHICZ)single crystals show the highest photoresponsivity of 3×10^3 A W^-1, photosensitivity of 2×10^4 and the detectivity can achieve 8.4×10^14 Jones. We also discovered good linear dependence of log(photosensitivity) versus the wavelength when the devices were illuminated with a series of sameintensity but different-wavelength lights. The organic phototransistors based on CHICZ single crystal have potential applications in wavelength-detection.
基金supported by the Ministry of Science and Technology of China(2018YFA0703200 and 2017YFA0204503)the National Natural Science Foundation of China(52121002,51733004,U21A6002,51725304 and 21875158)+1 种基金Tianjin Natural Science Foundation(20JCJQJC00300)China Postdoctoral Science Foundation(2021M692381)。
文摘Near-infrared organic phototransistors have wide application prospects in many fields.The active materials with the high mobility and near-infrared response are critical to building high-performance near-infrared organic phototransistors,which are scarce at present.Herein,a new charge transfer cocrystal using 5,7-dihydroindolo[2,3-b]carbazole(5,7-ICZ)as the donor and 2,2’-(benzo[1,2-b:4,5-b’]dithiophene-4,8-diylidene)dimalononitrile(DTTCNQ)as the acceptor is properly designed and prepared in a stoichiometric ratio(D:A=1:1),which not only displays a high electron mobility of 0.15 cm^(2)V^(-1)s^(-1) and very low dark current,but also can serve as the active layer materials in the region of near-infrared detection due to the narrowed band gap and good charge transport properties.A high photosensitivity of 1.8×10^(4),the ultrahigh photoresponsivity of 2,923 A W-1and the high detectivity of 4.26×10^(11)Jones of the organic near-infrared phototransistors are obtained.
