Hydrogels exhibit potential applications in smart wearable devices because of their exceptional sensitivity to various external stimuli.However,their applications are limited by challenges in terms of issues in biocom...Hydrogels exhibit potential applications in smart wearable devices because of their exceptional sensitivity to various external stimuli.However,their applications are limited by challenges in terms of issues in biocompatibility,custom shape,and self-healing.Herein,a conductive,stretchable,adaptable,self-healing,and biocompatible liquid metal GaInSn/Ni-based composite hydrogel is developed by incorporating a magnetic liquid metal into the hydrogel framework through crosslinking polyvinyl alcohol(PVA)with sodium tetraborate.The excellent stretchability and fast self-healing capability of the PVA/liquid metal hydrogel are derived from its abundant hydrogen binding sites and liquid metal fusion.Significantly,owing to the magnetic constituent,the PVA/liquid metal hydrogel can be guided remotely using an external magnetic field to a specific position to repair the broken wires with no need for manual operation.The composite hydrogel also exhibits sensitive deformation responses and can be used as a strain sensor to monitor various body motions.Additionally,the multifunctional hydrogel displays absorption-dominated electromagnetic interference(EMI)shielding properties.The total shielding performance of the composite hydrogel increases to~62.5 dB from~31.8 dB of the pure PVA hydrogel at the thickness of 3.0 mm.The proposed bioinspired multifunctional magnetic hydrogel demonstrates substantial application potential in the field of intelligent wearable devices.展开更多
In this work,we reported a high-performance-based ultraviolet-visible(UV-VIS)photodetector based on a TiO_(2)@GaO_(x)N_(y)-Ag heterostructure.Ag particles were introduced into TiO_(2)@GaO_(x)N_(y)to enhance the visibl...In this work,we reported a high-performance-based ultraviolet-visible(UV-VIS)photodetector based on a TiO_(2)@GaO_(x)N_(y)-Ag heterostructure.Ag particles were introduced into TiO_(2)@GaO_(x)N_(y)to enhance the visible light detection perfor-mance of the heterojunction device.At 380 nm,the responsivity and detectivity of TiO_(2)@GaO_(x)N_(y)-Ag were 0.94 A/W and 4.79×109 Jones,respectively,and they increased to 2.86 A/W and 7.96×1010 Jones at 580 nm.The rise and fall times of the response were 0.19/0.23 and 0.50/0.57 s,respectively.Uniquely,at 580 nm,the responsivity of fabricated devices is one to four orders of magnitude higher than that of the photodetectors based on TiO_(2),Ga_(2)O_(3),and other heterojunctions.The excellent optoelectronic characteristics of the TiO_(2)@GaO_(x)N_(y)-Ag heterojunction device could be mainly attributed to the synergistic effect of the type-Ⅱband structure of the metal-semiconductor-metal heterojunction and the plasmon resonance effect of Ag,which not only effectively promotes the separation of photogenerated carriers but also reduces the recombination rate.It is fur-ther illuminated by finite difference time domain method(FDTD)simulation and photoelectric measurements.The TiO_(2)@GaO_(x)N_(y)-Ag arrays with high-efficiency detection are suitable candidates for applications in energy-saving communica-tion,imaging,and sensing networks.展开更多
Amorphous In–Ga–Zn–O(a-IGZO)thin-film transistor(TFT)memories with novel p-SnO/n-SnO_(2) heterojunction charge trapping stacks(CTSs)are investigated comparatively under a maximum fabrication temperature of 280℃.Co...Amorphous In–Ga–Zn–O(a-IGZO)thin-film transistor(TFT)memories with novel p-SnO/n-SnO_(2) heterojunction charge trapping stacks(CTSs)are investigated comparatively under a maximum fabrication temperature of 280℃.Compared to a single p-SnO or n-SnO_(2) charge trapping layer(CTL),the heterojunction CTSs can achieve electrically programmable and erasable characteristics as well as good data retention.Of the two CTSs,the tunneling layer/p-SnO/nSnO_(2)/blocking layer architecture demonstrates much higher program efficiency,more robust data retention,and comparably superior erase characteristics.The resulting memory window is as large as 6.66 V after programming at 13 V/1 ms and erasing at-8 V/1 ms,and the ten-year memory window is extrapolated to be 4.41 V.This is attributed to shallow traps in p-SnO and deep traps in n-SnO_(2),and the formation of a built-in electric field in the heterojunction.展开更多
In these days,the increasing massive data are being produced and demanded to be processed with the rapid growth of information technology.It is difficult to rely solely on the shrinking of semiconductor devices and sc...In these days,the increasing massive data are being produced and demanded to be processed with the rapid growth of information technology.It is difficult to rely solely on the shrinking of semiconductor devices and scale-up of the integrated circuits(ICs)again in the foreseeable future.Exploring new materials,new-principle semiconductor devices and new computing architectures is becoming an urgent topic in this field.Ambipolar two-dimensional(2D)semiconductors,possessing excellent electrostatic field controllability and flexibly modulated major charge carriers,offer a possibility to construct reconfigurable devices and enable the ICs with new functions,showing great potential in computing capacity,energy efficiency,time delay and cost.This review focuses on the recent significant advancements in reconfigurable electronic and optoelectronic devices of ambipolar 2D semiconductors,and demonstrates their potential approach towards ICs,like reconfigurable circuits and neuromorphic chips.It is expected to help readers understand the device design principle of ambipolar 2D semiconductors,and push forward exploring more new-principle devices and new-architecture computing circuits,and even their product applications.展开更多
With the rapid development of the Internet of Things,there is a great demand for portable gas sensors.Metal oxide semiconductors(MOS)are one of the most traditional and well-studied gas sensing materials and have been...With the rapid development of the Internet of Things,there is a great demand for portable gas sensors.Metal oxide semiconductors(MOS)are one of the most traditional and well-studied gas sensing materials and have been widely used to prepare various commercial gas sensors.However,it is limited by high operating temperature.The current research works are directed towards fabricating high-performance flexible room-temperature(FRT)gas sensors,which are effective in simplifying the structure of MOS-based sensors,reducing power consumption,and expanding the application of portable devices.This article presents the recent research progress of MOS-based FRT gas sensors in terms of sensing mechanism,performance,flexibility characteristics,and applications.This review comprehensively summarizes and discusses five types of MOS-based FRT gas sensors,including pristine MOS,noble metal nanoparticles modified MOS,organic polymers modified MOS,carbon-based materials(carbon nanotubes and graphene derivatives)modified MOS,and two-dimensional transition metal dichalcogenides materials modified MOS.The effect of light-illuminated to improve gas sensing performance is further discussed.Furthermore,the applications and future perspectives of FRT gas sensors are also discussed.展开更多
The recently reported quasi-nonvolatile memory based on semi-floating gate architecture has attracted extensive attention thanks to its potential to bridge the large gap between volatile and nonvolatile memory.However...The recently reported quasi-nonvolatile memory based on semi-floating gate architecture has attracted extensive attention thanks to its potential to bridge the large gap between volatile and nonvolatile memory.However,the further extension of the refresh time in quasi-nonvolatile memory is limited by the charge leakage through the p-n junction.Here,based on the density of states engineered van der Waals heterostructures,the leakage of electrons from the floating gate to the channel is greatly suppressed.As a result,the refresh time is effectively extended to more than 100 s,which is the longest among all previously reported quasi-nonvolatile memories.This work provides a new idea to enhance the refresh time of quasi-nonvolatile memory by the density of states engineering and demonstrates great application potential for high-speed and low-power memory technology.展开更多
Semiconductive two dimensional(2D)materials have attracted significant research attention due to their rich band structures and promising potential for next-generation electrical devices.In this work,we investigate th...Semiconductive two dimensional(2D)materials have attracted significant research attention due to their rich band structures and promising potential for next-generation electrical devices.In this work,we investigate the MoS2 field-effect transistors(FETs)with a dual-gated(DG)architecture,which consists of symmetrical thickness for back gate(BG)and top gate(TG)dielectric.The thickness-dependent charge transport in our DG-MoS2 device is revealed by a four-terminal electrical measurement which excludes the contact influence,and the TCAD simulation is also applied to explain the experimental data.Our results indicate that the impact of quantum confinement effect plays an important role in the charge transport in the MoS2 channel,as it confines charge carriers in the center of the channel,which reduces the scattering and boosts the mobility compared to the single gating case.Furthermore,temperature-dependent transfer curves reveal that multi-layer MoS2 DG-FET is in the phonon-limited transport regime,while single layer MoS2 shows typical Coulomb impurity limited regime.展开更多
The recently reported quasi-nonvolatile memory based on semi-floating gate architecture has attracted extensive attention thanks to its potential to bridge the large gap between volatile and nonvolatile memory.However...The recently reported quasi-nonvolatile memory based on semi-floating gate architecture has attracted extensive attention thanks to its potential to bridge the large gap between volatile and nonvolatile memory.However,the further extension of the refresh time in quasi-nonvolatile memory is limited by the charge leakage through the p-n junction.Here,based on the density of states engineered van der Waals heterostructures,the leakage of electrons from the floating gate to the channel is greatly suppressed.As a result,the refresh time is effectively extended to more than 100 s,which is the longest among all previously reported quasi-nonvolatile memories.This work provides a new idea to enhance the refresh time of quasi-nonvolatile memory by the density of states engineering and demonstrates great application potential for high-speed and low-power memory technology.展开更多
Two-dimensional(2D)semiconductors can be utilized to continually miniaturize nanoscale electronic de-vices.However,achieving a practical solution for satisfying electrical contact with 2D semiconductors remains challe...Two-dimensional(2D)semiconductors can be utilized to continually miniaturize nanoscale electronic de-vices.However,achieving a practical solution for satisfying electrical contact with 2D semiconductors remains challenging.In this study,we developed a novel contact structure with transferred multilayer(t-ML)MoS 2 by integrating both edge and top contact.After in-situ plasma treatment for the edge of the MoS 2 channel and successive metal deposition,we achieved 16 times lower contact resistivity(22.8 kΩμm)than that of the top contacted devices.The thickness-dependent electrical measurement indicates that edge contact is highly effective with thick MoS 2 due to the alleviated current-crowding effect re-sulting from the small contact area.The temperature-dependent transport measurement further confirms the effective minimization of the influence from the Schottky barrier and tunnelling barrier.Finally,the simplified resistor network model and energy-band diagram were proposed to understand the carrier transport mechanism.Our work provides a practical strategy for achieving excellent electrical contact between bulk metals and 2D semiconductors,paving the way for future large-scale 2D electronic devices.展开更多
The unipolar photocurrent in conventional photodiodes(PDs)based on photovoltaic effect limits the output modes and potential versatility of these devices in photodetection.Bipolar photodiodes with photocurrent switchi...The unipolar photocurrent in conventional photodiodes(PDs)based on photovoltaic effect limits the output modes and potential versatility of these devices in photodetection.Bipolar photodiodes with photocurrent switching are emerging as a promising solution for obtaining photoelectric devices with unique and attractive functions,such as optical logic operation.Here,we design an all-solid-state chip-scale ultraviolet(UV)PD based on a hybrid GaN heterojunction with engineered bipolar polarized electric field.By introducing the polarization-induced photocurrent switching effect,the photocurrent direction can be switched in response to the wavelength of incident light at 0 V bias.In particular,the photocurrent direction exhibits negative when the irradiation wavelength is less than 315 nm,but positive when the wavelength is longer than 315 nm.The device shows a responsivity of up to−6.7 mA/W at 300 nm and 5.3 mA/W at 340 nm,respectively.In particular,three special logic gates in response to different dual UV light inputs are demonstrated via a single bipolar PD,which may be beneficial for future multifunctional UV photonic integrated devices and systems.展开更多
The unique features of ambipolar two-dimensional materials open up a great opportunity to build gate-programmable devices for reconfigurable circuit applications,e.g.,PN junctions for rectifier circuits.However,curren...The unique features of ambipolar two-dimensional materials open up a great opportunity to build gate-programmable devices for reconfigurable circuit applications,e.g.,PN junctions for rectifier circuits.However,current-reported rectifier circuits usually consist of one gate-programmable PN junction as the rectifier and one resistor as the load,which are not conductive to voltage output and large-scale integration.Here we propose an approach of complementary gate-programmable PN junctions to assemble reconfigurable rectifier circuit,which include two symmetric back-to-back black phosphorus(BP)/hexagonal boron nitride(h-BN)/graphene heterostructured semi-gate field-effect transistors(FETs)and perform complementary NP and PN junction like complementary metal-oxide-semiconductor(CMOS)circuit.The investigation exhibits that the circuit can effectively reconfigure the circuit with/without rectifying ability,and can process alternating current(AC)signals with the frequency prior 1 KHz and reconfiguration speed up to 25μs.We also achieve the reconfigurable rectifier circuit memory via complementary semi-floating gate FETs configuration.The complementary configuration here should be of low output impedance and low static power consumption,being beneficial for effective voltage output and large-scale integration.展开更多
Research of artificial synapses is increasing in popularity with the development of bioelectronics and the appearance of wearable devices.Because the high-temperature treatment process of inorganic materials is not co...Research of artificial synapses is increasing in popularity with the development of bioelectronics and the appearance of wearable devices.Because the high-temperature treatment process of inorganic materials is not compatible with flexible substrates,organic ferroelectric materials that are easier to process have emerged as alternatives.An organic synaptic device based on P(VDF-TrFE)was prepared in this study.The device showed reliable P/E endurance over 104 cycles and a data storage retention capability at 80℃ over 104 s.Simultaneously,it possessed excellent synaptic functions,including short-term/long-term synaptic plasticity and spike-timing-dependent plasticity.In addition,the ferroelectric performance of the device remained stable even under bending(7 mm bending radius)or after 500 bending cycles.This work shows that low-temperature processed organic ferroelectric materials can provide new ideas for the future development of wearable electronics and flexible artificial synapses.展开更多
Rheumatoid arthritis(RA)is a chronic inflammatory disease characterized by cartilage and bone damage with the presence of pannus formation which causes uncontrollable proliferation and invasion of fibroblast-like syno...Rheumatoid arthritis(RA)is a chronic inflammatory disease characterized by cartilage and bone damage with the presence of pannus formation which causes uncontrollable proliferation and invasion of fibroblast-like synoviocytes(FLS).Since rheumatoid arthritis is a chronic disorder,the patients normally need to undergo prolonged antirheumatic treatment with the use of disease-modifying antirheumatic drugs(DMARDs),steroids,and nonsteroidal anti-inflammatory drugs(NSAIDs).The efficacy of such long-term pharmaceutical intervention can be significantly affected by the development of drug resistance.The pathological relationship between rheumatoid arthritis and cancer hinted that some chemotherapeutic drugs,such as methotrexate(MTX),could be used for RA treatment.This idea was reinforced by the analysis of mutations in p53 tumor suppressor gene.Around 50%of p53 somatic mutations observed from various cancers are also identified in the synovium of RA patients1(Fig.1A).Of note,the hyperplastic synovium in RA with overexpressed p53 mutants contributed to the destruction of joints in patients with erosive RA.展开更多
Non-destructive stress characterization is essential for gate-all-around(GAA)nanosheet(NS)transistors technology,while it is a big challenge to be realized on nanometer-sized GAA devices by using traditional Micro-Ram...Non-destructive stress characterization is essential for gate-all-around(GAA)nanosheet(NS)transistors technology,while it is a big challenge to be realized on nanometer-sized GAA devices by using traditional Micro-Raman spectroscopy due to its light spot far exceeding the device.In this work,a non-destructive stress characterization methodology of confocal Raman spectroscopy was proposed and performed for GAANS device fabrication.Channel stress evolution along the fabrication process was successfully characterized by designing high-density NS array and analyzing the linear scanned spectra in different structures.The related mechanism of stress evolution was systematically studied by Sentaurus process simulation.Additionally,applying this methodology on detecting the bending of suspended NS after channel release process was demonstrated.Therefore,this work might provide a promising solution to realize in-line characterization of channel stress in GAA NS transistors and process monitor of NS channel integrity.展开更多
Synapses in biology provide a variety of functions for the neural system. Artificial synaptic electronics that mimic the biological neuron functions are basic building blocks and developing novel artificial synapses i...Synapses in biology provide a variety of functions for the neural system. Artificial synaptic electronics that mimic the biological neuron functions are basic building blocks and developing novel artificial synapses is essential for neuromorphic computation. Inspired by the unique features of biological synapses that the basic connection components of the nervous system and the parallelism, low power consumption, fault tolerance, self-learning and robustness of biological neural systems, artificial synaptic electronics and neuromorphic systems have the potential to overcome the traditional von Neumann bottleneck and create a new paradigm for dealing with complex problems such as pattern recognition, image classification, decision making and associative learning. Nowadays, two-dimensional(2 D) materials have drawn great attention in simulating synaptic dynamic plasticity and neuromorphic computing with their unique properties. Here we describe the basic concepts of bio-synaptic plasticity and learning, the 2 D materials library and its preparation. We review recent advances in synaptic electronics and artificial neuromorphic systems based on 2 D materials and provide our perspective in utilizing 2 D materials to implement synaptic electronics and neuromorphic systems in hardware.展开更多
Highly sensitive and selective hydrogen sulfide(H_(2)S)sensors based on hierarchical highly ordered SnO_(2) nanobowl branched ZnO nanowires(NWs)were synthesized via a sequential process combining hard template process...Highly sensitive and selective hydrogen sulfide(H_(2)S)sensors based on hierarchical highly ordered SnO_(2) nanobowl branched ZnO nanowires(NWs)were synthesized via a sequential process combining hard template processing,atomic-layer deposition,and hydrothermal processing.The hierarchical sensing materials were prepared in situ on microelectromechanical systems,which are expected to achieve high-performance gas sensors with superior sensitivity,long-term stability and repeatability,as well as low power consumption.Specifically,the hierarchical nanobowl SnO_(2)@ZnO NW sensor displayed a high sensitivity of 6.24,a fast response and recovery speed(i.e.,14 s and 39 s,respectively),and an excellent selectivity when detecting 1 ppm H_(2)S at 250°C,whose rate of resistance change(i.e.,5.24)is 2.6 times higher than that of the pristine SnO_(2) nanobowl sensor.The improved sensing performance could be attributed to the increased specific surface area,the formation of heterojunctions and homojunctions,as well as the additional reaction between ZnO and H_(2)S,which were confirmed by electrochemical characterization and band alignment analysis.Moreover,the well-structured hierarchical sensors maintained stable performance after a month,suggesting excellent stability and repeatability.In summary,such well-designed hierarchical highly ordered nanobowl SnO_(2)@ZnO NW gas sensors demonstrate favorable potential for enhanced sensitive and selective H_(2)S detection with long-term stability and repeatability.展开更多
Two-dimensional(2D)transition metal dichalcogenides(TMDs)such as molybdenum disulfide(M0S2)have been intensively investigated because of their exclusive physical properties for advaneed electronics and optoelectronics...Two-dimensional(2D)transition metal dichalcogenides(TMDs)such as molybdenum disulfide(M0S2)have been intensively investigated because of their exclusive physical properties for advaneed electronics and optoelectronics.In the present work,we study the M0S2 transistor based on a novel tri-gate device architecture,with dual-gate(Dual-G)in the channel and the buried side-gate(Side-G)for the source/drain regi ons.All gates can be in depe ndently con trolled without in terfere nee.For a MoS2 sheet with a thick ness of 3.6 nm,the Schottky barrier(SB)and non-overlapped channel region can be effectively tuned by electrostatically doping the source/drain regions with Side-G.Thus,the extri nsic resista nee can be effectively lowered,and a boost of the ON-state cur re nt can be achieved.Mean while,the cha nn el c ontrol remai ns efficient under the Dual-G mode,with an ON-OFF current ratio of 3 x 107 and subthreshold swing of 83 mV/decade.The corresponding band diagram is also discussed to illustrate the device operati on mechanism.This no vel device structure ope ns up a new way toward fabricati on of high-performance devices based on 2D-TMDs.展开更多
Optoelectronic devices for light or spectral signal detection are desired for use in a wide range of applications,including sensing,imaging,optical communications,and in situ characterization.However,existing photodet...Optoelectronic devices for light or spectral signal detection are desired for use in a wide range of applications,including sensing,imaging,optical communications,and in situ characterization.However,existing photodetectors indicate only light intensities,whereas multiphotosensor spectrometers require at least a chip-level assembly and can generate redundant signals for applications that do not need detailed spectral information.Inspired by human visual and psychological light perceptions,the compression of spectral information into representative intensities and colours may simplify spectrum processing at the device level.Here,we propose a concept of spectrum projection using a bandgap-gradient semiconductor cell for intensity and colour perception.Bandgap-gradient perovskites,prepared by a halide-exchanging method via dipping in a solution,are developed as the photoactive layer of the cell.The fabricated cell produces two output signals:one shows linear responses to both photon energy and flux,while the other depends on only photon flux.Thus,by combining the two signals,the single device can project the monochromatic and broadband spectra into the total photon fluxes and average photon energies(i.e.,intensities and hues),which are in good agreement with those obtained from a commercial photodetector and spectrometer.Under changing illumination in real time,the prepared device can instantaneously provide intensity and hue results.In addition,the flexibility and chemical/bio-sensing of the device via colour comparison are demonstrated.Therefore,this work shows a human visual-like method of spectrum projection and colour perception based on a single device,providing a paradigm for high-efficiency spectrum-processing applications.展开更多
Atomic layer deposition(ALD)can be used for wafer-scale synthesis of 2D materials.In this paper,a novel,reliable,secure,low-cost,and high-efficiency process for the fabrication of MoS2 is introduced and investigated.T...Atomic layer deposition(ALD)can be used for wafer-scale synthesis of 2D materials.In this paper,a novel,reliable,secure,low-cost,and high-efficiency process for the fabrication of MoS2 is introduced and investigated.The resulting 2D materials show high carrier-mobility as well as excellent electrical uniformity.Using molybdenum pentachloride(MoCl5)and hexamethyldisilathiane(HMDST)as ALD precursors,thickness-controlled MoS2 films are uniformly deposited on a 50 mm sapphire and a 100 mm silica substrate.This is done with a high growth-rate(up to 0.90Å/cycle).Large-scale top-gated FET arrays are fabricated using the films,with a room-temperature mobility of 0.56 cm2/(V·s)and a high on/off current ratio of 106.Excellent electrical uniformity is observed in the whole sapphire wafer.Additionally,logical circuits,including inverters,NAND,AND,NOR,and OR gates,are realized successfully with a high-k HfO2 dielectric layer.Our inverters exhibit a fast response frequency of 50 Hz and a DC-voltage gain of 4 at VDD=4 V.These results indicate that the new method has the potential to synthesize high quality MoS2 films on a large-scale,with hypo-toxicity and enhanced efficiency,which can facilitate a broader range of applications in the future.展开更多
基金the financial supports from the National Natural Science Foundation of China(52231007,51725101,11727807,22088101,52271167)the Shanghai Excellent Academic/Technological Leaders Program(19XD1400400)+4 种基金the Ministry of Science and Technology of China(973 Project Nos.2018YFA0209100 and 2021YFA1200600)the Fundamental Research Funds for the Central Universities(2022JCCXHH09)the Foundation for University Youth Key Teachers of Henan Province(2020GGJS170)the Support Program for Scientific and Technological Innovation Talents of Higher Education in Henan Province(21HASTIT004)Key Research Project of Zhejiang Lab(No.2021PE0AC02)。
文摘Hydrogels exhibit potential applications in smart wearable devices because of their exceptional sensitivity to various external stimuli.However,their applications are limited by challenges in terms of issues in biocompatibility,custom shape,and self-healing.Herein,a conductive,stretchable,adaptable,self-healing,and biocompatible liquid metal GaInSn/Ni-based composite hydrogel is developed by incorporating a magnetic liquid metal into the hydrogel framework through crosslinking polyvinyl alcohol(PVA)with sodium tetraborate.The excellent stretchability and fast self-healing capability of the PVA/liquid metal hydrogel are derived from its abundant hydrogen binding sites and liquid metal fusion.Significantly,owing to the magnetic constituent,the PVA/liquid metal hydrogel can be guided remotely using an external magnetic field to a specific position to repair the broken wires with no need for manual operation.The composite hydrogel also exhibits sensitive deformation responses and can be used as a strain sensor to monitor various body motions.Additionally,the multifunctional hydrogel displays absorption-dominated electromagnetic interference(EMI)shielding properties.The total shielding performance of the composite hydrogel increases to~62.5 dB from~31.8 dB of the pure PVA hydrogel at the thickness of 3.0 mm.The proposed bioinspired multifunctional magnetic hydrogel demonstrates substantial application potential in the field of intelligent wearable devices.
基金supported by National Natural Science Foundation of China(Nos.62027818,61874034,and 51861135105)Natural Science Foundation of Shanghai(No.18ZR1405000)Shanghai Science and Technology Innovation Program(No.19520711500).
文摘In this work,we reported a high-performance-based ultraviolet-visible(UV-VIS)photodetector based on a TiO_(2)@GaO_(x)N_(y)-Ag heterostructure.Ag particles were introduced into TiO_(2)@GaO_(x)N_(y)to enhance the visible light detection perfor-mance of the heterojunction device.At 380 nm,the responsivity and detectivity of TiO_(2)@GaO_(x)N_(y)-Ag were 0.94 A/W and 4.79×109 Jones,respectively,and they increased to 2.86 A/W and 7.96×1010 Jones at 580 nm.The rise and fall times of the response were 0.19/0.23 and 0.50/0.57 s,respectively.Uniquely,at 580 nm,the responsivity of fabricated devices is one to four orders of magnitude higher than that of the photodetectors based on TiO_(2),Ga_(2)O_(3),and other heterojunctions.The excellent optoelectronic characteristics of the TiO_(2)@GaO_(x)N_(y)-Ag heterojunction device could be mainly attributed to the synergistic effect of the type-Ⅱband structure of the metal-semiconductor-metal heterojunction and the plasmon resonance effect of Ag,which not only effectively promotes the separation of photogenerated carriers but also reduces the recombination rate.It is fur-ther illuminated by finite difference time domain method(FDTD)simulation and photoelectric measurements.The TiO_(2)@GaO_(x)N_(y)-Ag arrays with high-efficiency detection are suitable candidates for applications in energy-saving communica-tion,imaging,and sensing networks.
基金Project supported by the National Natural Science Foundation of China (Grant No.61874029)。
文摘Amorphous In–Ga–Zn–O(a-IGZO)thin-film transistor(TFT)memories with novel p-SnO/n-SnO_(2) heterojunction charge trapping stacks(CTSs)are investigated comparatively under a maximum fabrication temperature of 280℃.Compared to a single p-SnO or n-SnO_(2) charge trapping layer(CTL),the heterojunction CTSs can achieve electrically programmable and erasable characteristics as well as good data retention.Of the two CTSs,the tunneling layer/p-SnO/nSnO_(2)/blocking layer architecture demonstrates much higher program efficiency,more robust data retention,and comparably superior erase characteristics.The resulting memory window is as large as 6.66 V after programming at 13 V/1 ms and erasing at-8 V/1 ms,and the ten-year memory window is extrapolated to be 4.41 V.This is attributed to shallow traps in p-SnO and deep traps in n-SnO_(2),and the formation of a built-in electric field in the heterojunction.
基金Project supported by the National Natural Science Foundation of China (Grant No.62274037)the National Key Research and Development Program of China (Grant No.2018YFA0703703)+1 种基金the Ministry of Science and Technology of China (Grant No.2018YFE0118300)the State Key Laboratory of ASIC&System (Grant No.2021MS003)。
文摘In these days,the increasing massive data are being produced and demanded to be processed with the rapid growth of information technology.It is difficult to rely solely on the shrinking of semiconductor devices and scale-up of the integrated circuits(ICs)again in the foreseeable future.Exploring new materials,new-principle semiconductor devices and new computing architectures is becoming an urgent topic in this field.Ambipolar two-dimensional(2D)semiconductors,possessing excellent electrostatic field controllability and flexibly modulated major charge carriers,offer a possibility to construct reconfigurable devices and enable the ICs with new functions,showing great potential in computing capacity,energy efficiency,time delay and cost.This review focuses on the recent significant advancements in reconfigurable electronic and optoelectronic devices of ambipolar 2D semiconductors,and demonstrates their potential approach towards ICs,like reconfigurable circuits and neuromorphic chips.It is expected to help readers understand the device design principle of ambipolar 2D semiconductors,and push forward exploring more new-principle devices and new-architecture computing circuits,and even their product applications.
基金This work is supported by This work was supported by the National Key R&D Program of China(Nos.2020YFB2008604 and 2021YFB3202500)the National Natural Science Foundation of China(Nos.61874034 and 51861135105)+1 种基金the International Science and Technology Cooperation Program of Shanghai Science and Technology Innovation Action Plan(No.21520713300)Fudan University-CIOMP Joint Fund(E02632Y7H0).
文摘With the rapid development of the Internet of Things,there is a great demand for portable gas sensors.Metal oxide semiconductors(MOS)are one of the most traditional and well-studied gas sensing materials and have been widely used to prepare various commercial gas sensors.However,it is limited by high operating temperature.The current research works are directed towards fabricating high-performance flexible room-temperature(FRT)gas sensors,which are effective in simplifying the structure of MOS-based sensors,reducing power consumption,and expanding the application of portable devices.This article presents the recent research progress of MOS-based FRT gas sensors in terms of sensing mechanism,performance,flexibility characteristics,and applications.This review comprehensively summarizes and discusses five types of MOS-based FRT gas sensors,including pristine MOS,noble metal nanoparticles modified MOS,organic polymers modified MOS,carbon-based materials(carbon nanotubes and graphene derivatives)modified MOS,and two-dimensional transition metal dichalcogenides materials modified MOS.The effect of light-illuminated to improve gas sensing performance is further discussed.Furthermore,the applications and future perspectives of FRT gas sensors are also discussed.
基金This work was supported by the National Natural Science Foundation of China(61925402,61851402 and 61734003)Science and Technology Commission of Shanghai Municipality(19JC1416600)+2 种基金National Key Research and Development Program(2017YFB0405600)Shanghai Education Development Foundation and Shanghai Municipal Education Commission Shuguang Program(18SG01)China Postdoctoral Science Foundation(2019M661358,2019TQ0065).
文摘The recently reported quasi-nonvolatile memory based on semi-floating gate architecture has attracted extensive attention thanks to its potential to bridge the large gap between volatile and nonvolatile memory.However,the further extension of the refresh time in quasi-nonvolatile memory is limited by the charge leakage through the p-n junction.Here,based on the density of states engineered van der Waals heterostructures,the leakage of electrons from the floating gate to the channel is greatly suppressed.As a result,the refresh time is effectively extended to more than 100 s,which is the longest among all previously reported quasi-nonvolatile memories.This work provides a new idea to enhance the refresh time of quasi-nonvolatile memory by the density of states engineering and demonstrates great application potential for high-speed and low-power memory technology.
基金supported by the National Key Research and Development Program of China(2016YFA0203900,2018YFA0306101)the National Natural Science Foundation of China(Grant No.91964202)Shanghai Municipal Science and Technology Commission(18JC1410300)。
文摘Semiconductive two dimensional(2D)materials have attracted significant research attention due to their rich band structures and promising potential for next-generation electrical devices.In this work,we investigate the MoS2 field-effect transistors(FETs)with a dual-gated(DG)architecture,which consists of symmetrical thickness for back gate(BG)and top gate(TG)dielectric.The thickness-dependent charge transport in our DG-MoS2 device is revealed by a four-terminal electrical measurement which excludes the contact influence,and the TCAD simulation is also applied to explain the experimental data.Our results indicate that the impact of quantum confinement effect plays an important role in the charge transport in the MoS2 channel,as it confines charge carriers in the center of the channel,which reduces the scattering and boosts the mobility compared to the single gating case.Furthermore,temperature-dependent transfer curves reveal that multi-layer MoS2 DG-FET is in the phonon-limited transport regime,while single layer MoS2 shows typical Coulomb impurity limited regime.
文摘The recently reported quasi-nonvolatile memory based on semi-floating gate architecture has attracted extensive attention thanks to its potential to bridge the large gap between volatile and nonvolatile memory.However,the further extension of the refresh time in quasi-nonvolatile memory is limited by the charge leakage through the p-n junction.Here,based on the density of states engineered van der Waals heterostructures,the leakage of electrons from the floating gate to the channel is greatly suppressed.As a result,the refresh time is effectively extended to more than 100 s,which is the longest among all previously reported quasi-nonvolatile memories.This work provides a new idea to enhance the refresh time of quasi-nonvolatile memory by the density of states engineering and demonstrates great application potential for high-speed and low-power memory technology.
基金support of the National Key Re-search and Development Program(No.2016YFA0203900)the Natural Science Foundation of China(No.51802041)+1 种基金S.Dai ac-knowledges the support of the Shanghai Rising-star Program(No.20QA1402400)the Program for Professor of Special Appoint-ment(Eastern Scholar)at Shanghai Institutions of Higher Learning.
文摘Two-dimensional(2D)semiconductors can be utilized to continually miniaturize nanoscale electronic de-vices.However,achieving a practical solution for satisfying electrical contact with 2D semiconductors remains challenging.In this study,we developed a novel contact structure with transferred multilayer(t-ML)MoS 2 by integrating both edge and top contact.After in-situ plasma treatment for the edge of the MoS 2 channel and successive metal deposition,we achieved 16 times lower contact resistivity(22.8 kΩμm)than that of the top contacted devices.The thickness-dependent electrical measurement indicates that edge contact is highly effective with thick MoS 2 due to the alleviated current-crowding effect re-sulting from the small contact area.The temperature-dependent transport measurement further confirms the effective minimization of the influence from the Schottky barrier and tunnelling barrier.Finally,the simplified resistor network model and energy-band diagram were proposed to understand the carrier transport mechanism.Our work provides a practical strategy for achieving excellent electrical contact between bulk metals and 2D semiconductors,paving the way for future large-scale 2D electronic devices.
基金supported by the National Natural Science Foundation of China(Nos.62027818,51861135105,61874034,and 11974320)the National Key Research and Development Program of China(No.2021YFB3202500)International Science and Technology Cooperation Program of Shanghai Science and Technology Innovation Action Plan(No.21520713300).
文摘The unipolar photocurrent in conventional photodiodes(PDs)based on photovoltaic effect limits the output modes and potential versatility of these devices in photodetection.Bipolar photodiodes with photocurrent switching are emerging as a promising solution for obtaining photoelectric devices with unique and attractive functions,such as optical logic operation.Here,we design an all-solid-state chip-scale ultraviolet(UV)PD based on a hybrid GaN heterojunction with engineered bipolar polarized electric field.By introducing the polarization-induced photocurrent switching effect,the photocurrent direction can be switched in response to the wavelength of incident light at 0 V bias.In particular,the photocurrent direction exhibits negative when the irradiation wavelength is less than 315 nm,but positive when the wavelength is longer than 315 nm.The device shows a responsivity of up to−6.7 mA/W at 300 nm and 5.3 mA/W at 340 nm,respectively.In particular,three special logic gates in response to different dual UV light inputs are demonstrated via a single bipolar PD,which may be beneficial for future multifunctional UV photonic integrated devices and systems.
基金Authors acknowledge the financial supports from the Ministry of Science and Technology of China(No.2018YFE0118300)the National Key Research and Development Program of China(No.2018YFA0703703)+1 种基金the State Key Laboratory of ASIC&System(No.2021MS003)the Science and Technology Commission of Shanghai Municipality(No.20501130100).
文摘The unique features of ambipolar two-dimensional materials open up a great opportunity to build gate-programmable devices for reconfigurable circuit applications,e.g.,PN junctions for rectifier circuits.However,current-reported rectifier circuits usually consist of one gate-programmable PN junction as the rectifier and one resistor as the load,which are not conductive to voltage output and large-scale integration.Here we propose an approach of complementary gate-programmable PN junctions to assemble reconfigurable rectifier circuit,which include two symmetric back-to-back black phosphorus(BP)/hexagonal boron nitride(h-BN)/graphene heterostructured semi-gate field-effect transistors(FETs)and perform complementary NP and PN junction like complementary metal-oxide-semiconductor(CMOS)circuit.The investigation exhibits that the circuit can effectively reconfigure the circuit with/without rectifying ability,and can process alternating current(AC)signals with the frequency prior 1 KHz and reconfiguration speed up to 25μs.We also achieve the reconfigurable rectifier circuit memory via complementary semi-floating gate FETs configuration.The complementary configuration here should be of low output impedance and low static power consumption,being beneficial for effective voltage output and large-scale integration.
基金the National Key Research and Development Program of China(2021YFA1202600)National Natural Science Foundation of China(92064009,61904033,and 62004044)+2 种基金Shanghai Rising-Star Program(19QA1400600)the Program of Shanghai Subject Chief Scientist(18XD1402800)the young scientist project of MOE innovation platform.
文摘Research of artificial synapses is increasing in popularity with the development of bioelectronics and the appearance of wearable devices.Because the high-temperature treatment process of inorganic materials is not compatible with flexible substrates,organic ferroelectric materials that are easier to process have emerged as alternatives.An organic synaptic device based on P(VDF-TrFE)was prepared in this study.The device showed reliable P/E endurance over 104 cycles and a data storage retention capability at 80℃ over 104 s.Simultaneously,it possessed excellent synaptic functions,including short-term/long-term synaptic plasticity and spike-timing-dependent plasticity.In addition,the ferroelectric performance of the device remained stable even under bending(7 mm bending radius)or after 500 bending cycles.This work shows that low-temperature processed organic ferroelectric materials can provide new ideas for the future development of wearable electronics and flexible artificial synapses.
基金supported by an FDCT grant from the Macao Science and Technology Development Fund(Project code:0003/2019/AKP)the Joint Fund of Wuyi University-Macao(No.2019WGALH01).
文摘Rheumatoid arthritis(RA)is a chronic inflammatory disease characterized by cartilage and bone damage with the presence of pannus formation which causes uncontrollable proliferation and invasion of fibroblast-like synoviocytes(FLS).Since rheumatoid arthritis is a chronic disorder,the patients normally need to undergo prolonged antirheumatic treatment with the use of disease-modifying antirheumatic drugs(DMARDs),steroids,and nonsteroidal anti-inflammatory drugs(NSAIDs).The efficacy of such long-term pharmaceutical intervention can be significantly affected by the development of drug resistance.The pathological relationship between rheumatoid arthritis and cancer hinted that some chemotherapeutic drugs,such as methotrexate(MTX),could be used for RA treatment.This idea was reinforced by the analysis of mutations in p53 tumor suppressor gene.Around 50%of p53 somatic mutations observed from various cancers are also identified in the synovium of RA patients1(Fig.1A).Of note,the hyperplastic synovium in RA with overexpressed p53 mutants contributed to the destruction of joints in patients with erosive RA.
基金supported by the platform for the development of next generation integration circuit technology.
文摘Non-destructive stress characterization is essential for gate-all-around(GAA)nanosheet(NS)transistors technology,while it is a big challenge to be realized on nanometer-sized GAA devices by using traditional Micro-Raman spectroscopy due to its light spot far exceeding the device.In this work,a non-destructive stress characterization methodology of confocal Raman spectroscopy was proposed and performed for GAANS device fabrication.Channel stress evolution along the fabrication process was successfully characterized by designing high-density NS array and analyzing the linear scanned spectra in different structures.The related mechanism of stress evolution was systematically studied by Sentaurus process simulation.Additionally,applying this methodology on detecting the bending of suspended NS after channel release process was demonstrated.Therefore,this work might provide a promising solution to realize in-line characterization of channel stress in GAA NS transistors and process monitor of NS channel integrity.
基金supported by the National Natural Science Foundation of China(61622401,61851402 and 61734003)the National Key Research and Development Program of China(2017YFB0405600)+2 种基金Shanghai Education Development FoundationShanghai Municipal Education Commission Shuguang Program(18SG01)support from Shanghai Municipal Science and Technology Commission(18JC1410300)
文摘Synapses in biology provide a variety of functions for the neural system. Artificial synaptic electronics that mimic the biological neuron functions are basic building blocks and developing novel artificial synapses is essential for neuromorphic computation. Inspired by the unique features of biological synapses that the basic connection components of the nervous system and the parallelism, low power consumption, fault tolerance, self-learning and robustness of biological neural systems, artificial synaptic electronics and neuromorphic systems have the potential to overcome the traditional von Neumann bottleneck and create a new paradigm for dealing with complex problems such as pattern recognition, image classification, decision making and associative learning. Nowadays, two-dimensional(2 D) materials have drawn great attention in simulating synaptic dynamic plasticity and neuromorphic computing with their unique properties. Here we describe the basic concepts of bio-synaptic plasticity and learning, the 2 D materials library and its preparation. We review recent advances in synaptic electronics and artificial neuromorphic systems based on 2 D materials and provide our perspective in utilizing 2 D materials to implement synaptic electronics and neuromorphic systems in hardware.
基金This work was supported by the National Natural Science Foundation of China(No.U1632121,51861135105,and 61874034)Basic Research Project of Shanghai Science and Technology Innovation Action(No.17JC1400300)+1 种基金Natural Science Foundation of Shanghai(No.18ZR1405000)China Postdoctoral Science Foundation(No.TQ20190067).
文摘Highly sensitive and selective hydrogen sulfide(H_(2)S)sensors based on hierarchical highly ordered SnO_(2) nanobowl branched ZnO nanowires(NWs)were synthesized via a sequential process combining hard template processing,atomic-layer deposition,and hydrothermal processing.The hierarchical sensing materials were prepared in situ on microelectromechanical systems,which are expected to achieve high-performance gas sensors with superior sensitivity,long-term stability and repeatability,as well as low power consumption.Specifically,the hierarchical nanobowl SnO_(2)@ZnO NW sensor displayed a high sensitivity of 6.24,a fast response and recovery speed(i.e.,14 s and 39 s,respectively),and an excellent selectivity when detecting 1 ppm H_(2)S at 250°C,whose rate of resistance change(i.e.,5.24)is 2.6 times higher than that of the pristine SnO_(2) nanobowl sensor.The improved sensing performance could be attributed to the increased specific surface area,the formation of heterojunctions and homojunctions,as well as the additional reaction between ZnO and H_(2)S,which were confirmed by electrochemical characterization and band alignment analysis.Moreover,the well-structured hierarchical sensors maintained stable performance after a month,suggesting excellent stability and repeatability.In summary,such well-designed hierarchical highly ordered nanobowl SnO_(2)@ZnO NW gas sensors demonstrate favorable potential for enhanced sensitive and selective H_(2)S detection with long-term stability and repeatability.
基金This work was supported by the National Key Research and Development Program of China(Nos.2016YFA0203900 and 2018YFA0306101)Shanghai Municipal Science and Technology Commission(No.18JC1410300)Natural Science Foundation of China(No.61874154).
文摘Two-dimensional(2D)transition metal dichalcogenides(TMDs)such as molybdenum disulfide(M0S2)have been intensively investigated because of their exclusive physical properties for advaneed electronics and optoelectronics.In the present work,we study the M0S2 transistor based on a novel tri-gate device architecture,with dual-gate(Dual-G)in the channel and the buried side-gate(Side-G)for the source/drain regi ons.All gates can be in depe ndently con trolled without in terfere nee.For a MoS2 sheet with a thick ness of 3.6 nm,the Schottky barrier(SB)and non-overlapped channel region can be effectively tuned by electrostatically doping the source/drain regions with Side-G.Thus,the extri nsic resista nee can be effectively lowered,and a boost of the ON-state cur re nt can be achieved.Mean while,the cha nn el c ontrol remai ns efficient under the Dual-G mode,with an ON-OFF current ratio of 3 x 107 and subthreshold swing of 83 mV/decade.The corresponding band diagram is also discussed to illustrate the device operati on mechanism.This no vel device structure ope ns up a new way toward fabricati on of high-performance devices based on 2D-TMDs.
基金supported by the National Natural Science Foundation of China(61874029)the National Key Technologies R&D Programme of China(2015ZX02102-003).
文摘Optoelectronic devices for light or spectral signal detection are desired for use in a wide range of applications,including sensing,imaging,optical communications,and in situ characterization.However,existing photodetectors indicate only light intensities,whereas multiphotosensor spectrometers require at least a chip-level assembly and can generate redundant signals for applications that do not need detailed spectral information.Inspired by human visual and psychological light perceptions,the compression of spectral information into representative intensities and colours may simplify spectrum processing at the device level.Here,we propose a concept of spectrum projection using a bandgap-gradient semiconductor cell for intensity and colour perception.Bandgap-gradient perovskites,prepared by a halide-exchanging method via dipping in a solution,are developed as the photoactive layer of the cell.The fabricated cell produces two output signals:one shows linear responses to both photon energy and flux,while the other depends on only photon flux.Thus,by combining the two signals,the single device can project the monochromatic and broadband spectra into the total photon fluxes and average photon energies(i.e.,intensities and hues),which are in good agreement with those obtained from a commercial photodetector and spectrometer.Under changing illumination in real time,the prepared device can instantaneously provide intensity and hue results.In addition,the flexibility and chemical/bio-sensing of the device via colour comparison are demonstrated.Therefore,this work shows a human visual-like method of spectrum projection and colour perception based on a single device,providing a paradigm for high-efficiency spectrum-processing applications.
基金This work was supported by the National Natural Foundation of China(NSFC)(Nos.61704030 and 61522404)Shanghai Rising-Star Program(No.19QA1400600)+1 种基金the Program of Shanghai Subject Chief Scientist(No.18XD1402800)the Support Plans for the Youth Top-Notch Talents of China.
文摘Atomic layer deposition(ALD)can be used for wafer-scale synthesis of 2D materials.In this paper,a novel,reliable,secure,low-cost,and high-efficiency process for the fabrication of MoS2 is introduced and investigated.The resulting 2D materials show high carrier-mobility as well as excellent electrical uniformity.Using molybdenum pentachloride(MoCl5)and hexamethyldisilathiane(HMDST)as ALD precursors,thickness-controlled MoS2 films are uniformly deposited on a 50 mm sapphire and a 100 mm silica substrate.This is done with a high growth-rate(up to 0.90Å/cycle).Large-scale top-gated FET arrays are fabricated using the films,with a room-temperature mobility of 0.56 cm2/(V·s)and a high on/off current ratio of 106.Excellent electrical uniformity is observed in the whole sapphire wafer.Additionally,logical circuits,including inverters,NAND,AND,NOR,and OR gates,are realized successfully with a high-k HfO2 dielectric layer.Our inverters exhibit a fast response frequency of 50 Hz and a DC-voltage gain of 4 at VDD=4 V.These results indicate that the new method has the potential to synthesize high quality MoS2 films on a large-scale,with hypo-toxicity and enhanced efficiency,which can facilitate a broader range of applications in the future.
