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
Van der Waals(vdW)layered two-dimensional(2D)materials,which may have high carrier mobility,valley polarization,excellent mechanical properties and air stability,have been widely investigated before.We explore the pos...Van der Waals(vdW)layered two-dimensional(2D)materials,which may have high carrier mobility,valley polarization,excellent mechanical properties and air stability,have been widely investigated before.We explore the possibility of producing a spin-polarized two-dimensional electron gas(2DEG)in the heterojunction composed of insulators MoSi_(2)N_(4)and VSi_(2)N_(4)by using first-principles calculations.Due to the charge transfer effect,the 2DEG at the interface of the MoSi_(2)N_(4)/VSi_(2)N_(4)heterojunction is found.Further,for different kinds of stacking of heterojunctions,lattice strain and electric fields can effectively tune the electronic structures and lead to metal-to-semiconductor transition.Under compressive strain or electric field parallel to c axis,the 2DEG disappears and band gap opening occurs.On the contrary,interlayer electron transfer enforces the system to become metallic under the condition of tensile strain or electric field anti-parallel to c axis.These changes are mainly attributed to electronic redistribution and orbitals’reconstruction.In addition,we reveal that MoSi_(2)N_(4)/VSi_(2)N_(4)lateral heterojunctions of armchair and zigzag edges exhibit different electronic properties,such as a large band gap semiconductor and a metallic state.Our findings provide insights into electronic band engineering of MoSi_(2)N_(4)/VSi_(2)N_(4)heterojunctions and pave the way for future spintronics applications.展开更多
Two-dimensional(2D)materials have attracted increasing attention for their outstanding structural and electrical properties.However,for mass-production of field effect transistors(FETs)and potential applications in in...Two-dimensional(2D)materials have attracted increasing attention for their outstanding structural and electrical properties.However,for mass-production of field effect transistors(FETs)and potential applications in integrated circuits,large-area and uniform 2D thin films with high mobility,large on-off ratio,and desired polarity are needed to synthesize firstly.Here,a transfer-free growth method for platinum diselenide(PtSe2)films has been developed.The PtSe2 films have been synthesized with various thicknesses in centimeter-sized scale.Typical FET made from a few layer PtSe2 show p-type unipolar,with a high field-effect hole mobility of 6.2 cm^(2) V^(−1) s^(−1) and an on-off ratio of 5×10^(3).The versatile semimetal-unipolar-ambipolar transition in synthesized PtSe2 films is also firstly observed as the thickness thinning.This work realizes the large-scale preparation of PtSe2 with prominent electrical properties and provides a new strategy for polarity's modulation.展开更多
The advent of low-dimensional materials with peculiar structure and superb band properties provides a new canonical form for the development of photodetectors.However,the limited exploitation of basic properties makes...The advent of low-dimensional materials with peculiar structure and superb band properties provides a new canonical form for the development of photodetectors.However,the limited exploitation of basic properties makes it difficult for devices to stand out.Here,we demonstrate a hybrid heterostructure with ultrathin vanadium dioxide film and molybdenum ditelluride nanoflake.Vanadium dioxide is a classical semiconductor with a narrow bandgap,a high temperature coefficient of resistance,and phase transformation.Molybdenum ditelluride,a typical two-dimensional material,is often used to construct optoelectronic devices.The heterostructure can realize three different functional modes:(i)the p-n junction exhibits ultrasensitive detection(450 nm-2μm)with a dark current down to 0.2 pA and a response time of 17μs,(ii)the Schottky junction works stably under extreme conditions such as a high temperature of 400 K,and(iii)the bolometer shows ultrabroad spectrum detection exceeding 10μm.The flexible switching between the three modes makes the heterostructure a potential candidate for next-generation photodetectors from visible to longwave infrared radiation(LWIR).This type of photodetector combines versatile detection modes,shedding light on the hybrid application of novel and traditional materials,and is a prototype of advanced optoelectronic devices.展开更多
Manganese oxides with a perovskite-type Re_(1-x)D_xMnO_3(Re:heavy rare-earth elements,D:divalent alkali metal)structure have attracted interest because of the complex interaction between their electrons,lattices,and s...Manganese oxides with a perovskite-type Re_(1-x)D_xMnO_3(Re:heavy rare-earth elements,D:divalent alkali metal)structure have attracted interest because of the complex interaction between their electrons,lattices,and spins[1-5].Generally,manganese oxides with the structure Re_(1-x)D_xMnO_3 have special properties.For example,the half-metallic manganites,such as La_(2/3)Sr_(1/3)MnO_3 and La_(2/3)Ca_(1/3)MnO_3,wherein the conduction electrons are completely spin polarized。展开更多
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supported by the National Natural Science Foundation of China(Grant Nos.12074241,52130204,and 11929401)the Science and Technology Commission of Shanghai Municipality(Grant Nos.22XD1400900,20501130600,21JC1402600,and 22YF1413300)+5 种基金High Performance Computing Center,Shanghai UniversityKey Research Project of Zhejiang Lab(Grant No.2021PE0AC02)the supports from the open projects of Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials(Anhui University of Technology),Ministry of Education(Grant No.GFST2022KF08)State Key Laboratory of Surface Physics(Fudan University)(Grant No.KF202210)State Key Laboratory of Infrared Physics,Shanghai Institute of Technical Physics,Chinese Academy of Sciences(Grant No.SITP-NLIST-YB-2022-08)the support of China Scholarship Council。
文摘Van der Waals(vdW)layered two-dimensional(2D)materials,which may have high carrier mobility,valley polarization,excellent mechanical properties and air stability,have been widely investigated before.We explore the possibility of producing a spin-polarized two-dimensional electron gas(2DEG)in the heterojunction composed of insulators MoSi_(2)N_(4)and VSi_(2)N_(4)by using first-principles calculations.Due to the charge transfer effect,the 2DEG at the interface of the MoSi_(2)N_(4)/VSi_(2)N_(4)heterojunction is found.Further,for different kinds of stacking of heterojunctions,lattice strain and electric fields can effectively tune the electronic structures and lead to metal-to-semiconductor transition.Under compressive strain or electric field parallel to c axis,the 2DEG disappears and band gap opening occurs.On the contrary,interlayer electron transfer enforces the system to become metallic under the condition of tensile strain or electric field anti-parallel to c axis.These changes are mainly attributed to electronic redistribution and orbitals’reconstruction.In addition,we reveal that MoSi_(2)N_(4)/VSi_(2)N_(4)lateral heterojunctions of armchair and zigzag edges exhibit different electronic properties,such as a large band gap semiconductor and a metallic state.Our findings provide insights into electronic band engineering of MoSi_(2)N_(4)/VSi_(2)N_(4)heterojunctions and pave the way for future spintronics applications.
基金support from the National Natural Science Foundation of China(61835012,61722408,21771040,61574151,61574152)the Key Research Project of Frontier Sciences of Chinese Academy of Sciences(QYZDB-SSW-JSC016,QYZDB-SSW-JSC042)+1 种基金the National Key Research and Development Program of China(2017YFA0207303,2016YFA0203900)the 1000 Plan Program for Young Talents.
文摘Two-dimensional(2D)materials have attracted increasing attention for their outstanding structural and electrical properties.However,for mass-production of field effect transistors(FETs)and potential applications in integrated circuits,large-area and uniform 2D thin films with high mobility,large on-off ratio,and desired polarity are needed to synthesize firstly.Here,a transfer-free growth method for platinum diselenide(PtSe2)films has been developed.The PtSe2 films have been synthesized with various thicknesses in centimeter-sized scale.Typical FET made from a few layer PtSe2 show p-type unipolar,with a high field-effect hole mobility of 6.2 cm^(2) V^(−1) s^(−1) and an on-off ratio of 5×10^(3).The versatile semimetal-unipolar-ambipolar transition in synthesized PtSe2 films is also firstly observed as the thickness thinning.This work realizes the large-scale preparation of PtSe2 with prominent electrical properties and provides a new strategy for polarity's modulation.
基金supported by the Natural Science Foundation of China(Grant Nos.61835012,61722408,61725505,61521005,and 61905267)the Key Research Project of Frontier Sciences of the Chinese Academy of Sciences(Grant Nos.QYZDB-SSW-JSC016 and QYZDY-SSW-JSC042)+4 种基金the Key Research Program of Frontier Science,CAS(Grant No.ZDBS-LY-JSC045)the Major State Basic Research Development Program(Grant No.2016YFA0203900)the National Postdoctoral Program for Innovative Talents(BX20180329)the Natural Science Foundation of Shanghai(Grant Nos.16ZR1447600 and 17JC1400302)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB44000000).
文摘The advent of low-dimensional materials with peculiar structure and superb band properties provides a new canonical form for the development of photodetectors.However,the limited exploitation of basic properties makes it difficult for devices to stand out.Here,we demonstrate a hybrid heterostructure with ultrathin vanadium dioxide film and molybdenum ditelluride nanoflake.Vanadium dioxide is a classical semiconductor with a narrow bandgap,a high temperature coefficient of resistance,and phase transformation.Molybdenum ditelluride,a typical two-dimensional material,is often used to construct optoelectronic devices.The heterostructure can realize three different functional modes:(i)the p-n junction exhibits ultrasensitive detection(450 nm-2μm)with a dark current down to 0.2 pA and a response time of 17μs,(ii)the Schottky junction works stably under extreme conditions such as a high temperature of 400 K,and(iii)the bolometer shows ultrabroad spectrum detection exceeding 10μm.The flexible switching between the three modes makes the heterostructure a potential candidate for next-generation photodetectors from visible to longwave infrared radiation(LWIR).This type of photodetector combines versatile detection modes,shedding light on the hybrid application of novel and traditional materials,and is a prototype of advanced optoelectronic devices.
基金supported by the Major State Basic Research Development Program(Grant No.2013CB922302)the National Natural Science Foundation of China(Grant No.11374320)
文摘Manganese oxides with a perovskite-type Re_(1-x)D_xMnO_3(Re:heavy rare-earth elements,D:divalent alkali metal)structure have attracted interest because of the complex interaction between their electrons,lattices,and spins[1-5].Generally,manganese oxides with the structure Re_(1-x)D_xMnO_3 have special properties.For example,the half-metallic manganites,such as La_(2/3)Sr_(1/3)MnO_3 and La_(2/3)Ca_(1/3)MnO_3,wherein the conduction electrons are completely spin polarized。
基金We thank the financial supports by the National Natural Science Foundation of China (Nos.21221062 and 21521091) and the National Basic Research Program of China (973 program,No.2013CB932800).
