Silica(SiO_(2))anodes are promising candidates for enhancing the energy density of next-generation Li-ion batteries,offering a compelling combination of high storage capacity,stable cycling performance,low cost,and su...Silica(SiO_(2))anodes are promising candidates for enhancing the energy density of next-generation Li-ion batteries,offering a compelling combination of high storage capacity,stable cycling performance,low cost,and sustainability.This performance stems from SiO_(2) unique lithiation mechanism,which involves its conversion to electroactive silicon(Si)and electrochemically inactive species.However,widespread adoption of SiO_(2) anodes is hindered by their slow initial lithiation.展开更多
Strain engineering has arisen as a powerful technique to tune the electronic and optical properties of twod imensional semiconductors like molybdenum disulfide(MoS_(2)).Although several theoretical works predicted tha...Strain engineering has arisen as a powerful technique to tune the electronic and optical properties of twod imensional semiconductors like molybdenum disulfide(MoS_(2)).Although several theoretical works predicted that biaxial strain would be more effective than uniaxial strain to tune the band structure of MoS_(2),a direct experimental verification is still missing in the literature.Here we implemented a simple experimental setup that allows to apply biaxial strain through the bending of a cruciform polymer substrate.We used the setup to study the effect of biaxial strain on the differential reflectance spectra of 12 single-layer MoS_(2)flakes finding a redshift of the excitonic features at a rate between-40 meV/%and-110 meV/%of biaxial tension.We also directly compare the effect of biaxi al and uniaxial strain on the same single-layer MoS_(2)finding that the biaxial strain gauge factor is 2.3 times larger than the uniaxial strain one.展开更多
Paper-based devices have attracted extensive attention due to the growing demand for disposable flexible electronics.Herein,we integrate semiconducting devices on cellulose paper substrate through a simple abrasion te...Paper-based devices have attracted extensive attention due to the growing demand for disposable flexible electronics.Herein,we integrate semiconducting devices on cellulose paper substrate through a simple abrasion technique that yields high-performance photodetectors.A solvent-free WS_(2) film deposited on paper favors an effective electron-hole separation and hampers recombination.The as-prepared paper-based WS2 photodetectors exhibit a sensitive photoresponse over a wide spectral range spanning from ultraviolet(365 nm)to near-infrared(940 nm).Their responsivity value reaches up to~270 mA W^(−1) at 35 V under a power density of 35 mW cm^(−2).A high performance photodetector was achieved by controlling the environmental exposure as the ambient oxygen molecules were found to decrease the photoresponse and stability of the WS_(2) photodetector.Furthermore,we have built a spectrometer using such a paperbased WS_(2) device as the photodetecting component to illustrate its potential application.The present work could promote the development of cost-effective disposable photodetection devices.展开更多
We present a method to fabricate handcrafted thermoelectric devices on standard office paper substrates.The devices are based on thin films of WS_(2),Te,and BP(P-type semiconductors)and TiS_(3)and TiS_(2)(N-type semic...We present a method to fabricate handcrafted thermoelectric devices on standard office paper substrates.The devices are based on thin films of WS_(2),Te,and BP(P-type semiconductors)and TiS_(3)and TiS_(2)(N-type semiconductors),deposited by simply rubbing powder of these materials against paper.The thermoelectric properties of these semiconducting films revealed maximum Seebeck coefficients of(+1.32±0.27)mV K^(-1)and(-0.82±0.15)mV K^(-1)for WS_(2)and TiS_(3),respectively.Additionally,Peltier elements were fabricated by interconnecting the P-and N-type films with graphite electrodes.A thermopower value up to 6.11 mV K^(-1)was obtained when the Peltier element were constructed with three junctions.The findings of this work show proof-of-concept devices to illustrate the potential application of semiconducting van der Waals materials in future thermoelectric power generation as well as temperature sensing for low-cost disposable electronic devices.展开更多
Magnetization reversal processes of hexagonal dense arrays of bi-segmented Ni and Fe50Co50 nanowires consisting of two well defined diameters (45 and 80 nm) have been studied.The nanowires were grown inside of tailore...Magnetization reversal processes of hexagonal dense arrays of bi-segmented Ni and Fe50Co50 nanowires consisting of two well defined diameters (45 and 80 nm) have been studied.The nanowires were grown inside of tailored pores of anodic alumina templates by combined anodization,atomic layer deposition (ALD) and electrodeposition techniques.The experiments have allowed to identify their two-step magnetization reversal process ascribed to the respective segments of different diameter.This is concluded from the differential susceptibility observed in the hysteresis loops,contrary to those for nanowires with homogeneous diameter.These results are also confirmed by the first-order reversal curve (FORC) distribution diagrams,where an elongation parallel to the interaction axis around two coercive field values is obtained,which is correlated to the difference in diameter of the two segments.This well-defined two-step magnetization reversal process through the nanowire diameter design is thought to be very useful for the advanced control of the remagnetization in arrays of magnetic multidomain systems.展开更多
Two-dimensional materials are attractive for constructing high-performance photonic chip-integrated photodetectors because of their remarkable electronic and optical properties and dangling-bond-free surfaces.However,...Two-dimensional materials are attractive for constructing high-performance photonic chip-integrated photodetectors because of their remarkable electronic and optical properties and dangling-bond-free surfaces.However,the reported chip-integrated two-dimensional material photodetectors were mainly implemented with the configuration of metalsemiconductor-metal,suffering from high dark currents and low responsivities at high operation speed.Here,we report a van der Waals PN heterojunction photodetector,composed of p-type black phosphorous and n-type molybdenum telluride,integrated on a silicon nitride waveguide.The built-in electric field of the PN heterojunction significantly suppresses the dark current and improves the responsivity.Under a bias of 1 V pointing from n-type molybdenum telluride to p-type black phosphorous,the dark current is lower than 7 nA,which is more than two orders of magnitude lower than those reported in other waveguide-integrated black phosphorus photodetectors.An intrinsic responsivity up to 577 mA W^(−1) is obtained.Remarkably,the van der Waals PN heterojunction is tunable by the electrostatic doping to further engineer its rectification and improve the photodetection,enabling an increased responsivity of 709 mA W^(−1).Besides,the heterojunction photodetector exhibits a response bandwidth of~1.0 GHz and a uniform photodetection over a wide spectral range,as experimentally measured from 1500 to 1630 nm.The demonstrated chip-integrated van der Waals PN heterojunction photodetector with low dark current,high responsivity and fast response has great potentials to develop high-performance on-chip photodetectors for various photonic integrated circuits based on silicon,lithium niobate,polymer,etc.展开更多
By combining ab initio calculations and experiments, we demonstrate how the band gap of the transition metal trichalcogenide TiS3 can be modified by inducing tensile or compressive strain. In addition, using our calcu...By combining ab initio calculations and experiments, we demonstrate how the band gap of the transition metal trichalcogenide TiS3 can be modified by inducing tensile or compressive strain. In addition, using our calculations, we predicted that the material would exhibit a transition from a direct to an indirect band gap upon application of a compressive strain in the direction of easy electrical transport. The ability to control the band gap and its nature could have a significant impact on the use of TiS3 for optical applications. We go on to verify our prediction via optical absorption experiments that demonstrate a band gap increase of up to 9% （from 0.99 to 1.08 eV） upon application of tensile stress along the easy transport direction.展开更多
We propose a realistic topological p-n junction （TPNJ） by matching two Bi2Se3 （0001） slabs with opposite arrangements of planar twin boundary defects. The atomistic modeling of such a device leads to dislocation d...We propose a realistic topological p-n junction （TPNJ） by matching two Bi2Se3 （0001） slabs with opposite arrangements of planar twin boundary defects. The atomistic modeling of such a device leads to dislocation defects in the hexagonal lattice in several quintuple layers. Nevertheless, total energy calculations reveal that the interface relaxes, yielding a smooth geometrical transition that preserves the nearest-neighbors fcc-type geometry throughout these defect layers. The electronic, magnetic, and transport properties of the junction have then been calculated at the ab initio level under open boundary conditions, i.e., employing a thin-film geometry that is infinite along the electron transport direction. Indeed, a p-n junction is obtained with a built-in potential as large as 350 meV. The calculations further reveal the spin texture across the interface with unprecedented detail. As the main result, we obtain non-negligible transmission probabilities around the F point, which involve an electron spin-flip process while crossing the interface.展开更多
Cl-functionalized scanning tunneling microscopy （STM） tips are fabricated by modifying a tungsten STM tip in situ on islands of ultrathin NaCI（100） films on Au（111） surfaces. The functionalized tips are used to ...Cl-functionalized scanning tunneling microscopy （STM） tips are fabricated by modifying a tungsten STM tip in situ on islands of ultrathin NaCI（100） films on Au（111） surfaces. The functionalized tips are used to achieve clear atomic- resolution imaging of NaCI（100） islands. In comparison with bare metal tips, the chemically modified tips yield drastically enhanced spatial resolution as well as contrast reversal in STM topographs, implying that Na atoms, rather than C1 atoms, are imaged as protrusions. STM simulations based on a Green＇s function formalism reveal that the experimentally observed contrast reversal in the STM topographs is due to the highly localized character of the Cl-pz states at the tip apex. An additional remarkable characteristic of the modified tips is that in dI/dV maps, a Na atom appears as a ring with a diameter that depends crucially on the tip-sample distance.展开更多
Random lasing is observed in optically active resonators in the presence of disorder.As the optical cavities involved are open,the modes are coupled,and energy may pour from one state to another provided that they are...Random lasing is observed in optically active resonators in the presence of disorder.As the optical cavities involved are open,the modes are coupled,and energy may pour from one state to another provided that they are spatially overlapping.Although the electromagnetic modes are spatially localized,our system may be actively switched to a collective state,presenting a novel form of non-locality revealed by a high degree of spectral correlation between the light emissions collected at distant positions.In a nutshell,light may be stored in a disordered nonlinear structure in different fashions that strongly differ in their spatial properties.This effect is experimentally demonstrated and theoretically explained in titania clusters embedded in a dye,and it provides clear evidence of a transition to a multimodal collective emission involving the entire spatial extent of the disordered system.Our results can be used to develop a novel type of miniaturized,actively controlled all-optical chip.展开更多
基金supported by the Norwegian Research Council project number 315947support from the Research Council of Norway through the Norwegian Center for Transmission Electron Microscopy,NORTEM(197405/F50)+2 种基金The Norwegian Infrastructure for Microand Nanofabrication,Nor Fab(245963/F50)Grants No.PCI2022-132993 funded by MCIN/AEI/10.13039/501100011033 and DGA/M4 from Diputación General de Aragónfinancial support and for provision of synchrotron radiation facilities at BM25-Sp Line(PIE 201060E 013 and PIE 202160 E 030)。
文摘Silica(SiO_(2))anodes are promising candidates for enhancing the energy density of next-generation Li-ion batteries,offering a compelling combination of high storage capacity,stable cycling performance,low cost,and sustainability.This performance stems from SiO_(2) unique lithiation mechanism,which involves its conversion to electroactive silicon(Si)and electrochemically inactive species.However,widespread adoption of SiO_(2) anodes is hindered by their slow initial lithiation.
基金funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement n° 755655, ERC-St G 2017 project 2D-TOPSENSE)the support from the Spanish Ministry of Economy, Industry and Competitiveness through a Juan de la Cierva-formación fellowship 2017 FJCI2017-32919.
文摘Strain engineering has arisen as a powerful technique to tune the electronic and optical properties of twod imensional semiconductors like molybdenum disulfide(MoS_(2)).Although several theoretical works predicted that biaxial strain would be more effective than uniaxial strain to tune the band structure of MoS_(2),a direct experimental verification is still missing in the literature.Here we implemented a simple experimental setup that allows to apply biaxial strain through the bending of a cruciform polymer substrate.We used the setup to study the effect of biaxial strain on the differential reflectance spectra of 12 single-layer MoS_(2)flakes finding a redshift of the excitonic features at a rate between-40 meV/%and-110 meV/%of biaxial tension.We also directly compare the effect of biaxi al and uniaxial strain on the same single-layer MoS_(2)finding that the biaxial strain gauge factor is 2.3 times larger than the uniaxial strain one.
基金Felix Carrascoso (ICMM-CSIC) for support with the metal evaporationfunding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement n°755655,ERC-StG 2017 project2D-TOPSENSE)+5 种基金the Ministry of Science and Innovation (Spain) through the project PID2020-115566RB-I00support from the National Natural Science Foundation of China under grant No.61704129 and No.62011530438the Key Research and Development Program of Shaanxi (Program No.2021KW-02)Fundamental Research Funds for the Central Universities (JB211409)the grant from China Scholarship Council (CSC) under No.201908610178the support from European Union’s Horizon 2020 research and innovation program under the grant agreement 956813 (2Exciting)。
文摘Paper-based devices have attracted extensive attention due to the growing demand for disposable flexible electronics.Herein,we integrate semiconducting devices on cellulose paper substrate through a simple abrasion technique that yields high-performance photodetectors.A solvent-free WS_(2) film deposited on paper favors an effective electron-hole separation and hampers recombination.The as-prepared paper-based WS2 photodetectors exhibit a sensitive photoresponse over a wide spectral range spanning from ultraviolet(365 nm)to near-infrared(940 nm).Their responsivity value reaches up to~270 mA W^(−1) at 35 V under a power density of 35 mW cm^(−2).A high performance photodetector was achieved by controlling the environmental exposure as the ambient oxygen molecules were found to decrease the photoresponse and stability of the WS_(2) photodetector.Furthermore,we have built a spectrometer using such a paperbased WS_(2) device as the photodetecting component to illustrate its potential application.The present work could promote the development of cost-effective disposable photodetection devices.
基金funded by the European Research Council(ERC)under the European Union's Horizon 2020 research and innovation program(grant agreement no.755655,ERC-StG 2017 project 2D-TOPSENSE)the Ministry of Science and Innovation(Spain)through the project PID2020-115566RB-I00+7 种基金the Distinguished Scientist Fellowship Program(DSFP)at King Saud University for partial funding of this workfinancial support from the Agencia Estatal de Investigación of Spain(Grants PID2019-106820RB,RTI2018-097180-B-100,and PGC2018-097018-B-I00)the Junta de Castilla y León(Grants SA256P18 and SA121P20),including funding by ERDF/FEDERfinancial support from Universidad Complutense de Madrid and European Commission(MSCA COFUND UNA4CAREER grant.Project number 4129252)financial support from MICINN(Spain)through the program Juan de la Cierva-Incorporaciónthe financial support of the Spanish Ministry of Industry and Competitiveness to the project MAT2017-84496-Rfinancial support from the Ministry of Science and Innovation(Spain)through the project RT2018-099794-B-100financial support from the Ministry de Universities(Spain)(Ph.D.contract FPU19/04224)
文摘We present a method to fabricate handcrafted thermoelectric devices on standard office paper substrates.The devices are based on thin films of WS_(2),Te,and BP(P-type semiconductors)and TiS_(3)and TiS_(2)(N-type semiconductors),deposited by simply rubbing powder of these materials against paper.The thermoelectric properties of these semiconducting films revealed maximum Seebeck coefficients of(+1.32±0.27)mV K^(-1)and(-0.82±0.15)mV K^(-1)for WS_(2)and TiS_(3),respectively.Additionally,Peltier elements were fabricated by interconnecting the P-and N-type films with graphite electrodes.A thermopower value up to 6.11 mV K^(-1)was obtained when the Peltier element were constructed with three junctions.The findings of this work show proof-of-concept devices to illustrate the potential application of semiconducting van der Waals materials in future thermoelectric power generation as well as temperature sensing for low-cost disposable electronic devices.
文摘Magnetization reversal processes of hexagonal dense arrays of bi-segmented Ni and Fe50Co50 nanowires consisting of two well defined diameters (45 and 80 nm) have been studied.The nanowires were grown inside of tailored pores of anodic alumina templates by combined anodization,atomic layer deposition (ALD) and electrodeposition techniques.The experiments have allowed to identify their two-step magnetization reversal process ascribed to the respective segments of different diameter.This is concluded from the differential susceptibility observed in the hysteresis loops,contrary to those for nanowires with homogeneous diameter.These results are also confirmed by the first-order reversal curve (FORC) distribution diagrams,where an elongation parallel to the interaction axis around two coercive field values is obtained,which is correlated to the difference in diameter of the two segments.This well-defined two-step magnetization reversal process through the nanowire diameter design is thought to be very useful for the advanced control of the remagnetization in arrays of magnetic multidomain systems.
基金supported by the National Key R&D Program of China(Grant Nos.2018YFA0307200 and 2017YFA0303800)the National Natural Science Foundation of China(Grant Nos.61905198,61775183,11634010,and 61675171)+1 种基金Key Research and Development Program in Shaanxi Province of China(Grant Nos.2017KJXX-12,2018JM1058,and 2018KW-009)the Fundamental Research Funds for the Central Universities(Grant Nos.3102017jc01001,3102018jcc034,and 3102017HQZZ022)。
文摘Two-dimensional materials are attractive for constructing high-performance photonic chip-integrated photodetectors because of their remarkable electronic and optical properties and dangling-bond-free surfaces.However,the reported chip-integrated two-dimensional material photodetectors were mainly implemented with the configuration of metalsemiconductor-metal,suffering from high dark currents and low responsivities at high operation speed.Here,we report a van der Waals PN heterojunction photodetector,composed of p-type black phosphorous and n-type molybdenum telluride,integrated on a silicon nitride waveguide.The built-in electric field of the PN heterojunction significantly suppresses the dark current and improves the responsivity.Under a bias of 1 V pointing from n-type molybdenum telluride to p-type black phosphorous,the dark current is lower than 7 nA,which is more than two orders of magnitude lower than those reported in other waveguide-integrated black phosphorus photodetectors.An intrinsic responsivity up to 577 mA W^(−1) is obtained.Remarkably,the van der Waals PN heterojunction is tunable by the electrostatic doping to further engineer its rectification and improve the photodetection,enabling an increased responsivity of 709 mA W^(−1).Besides,the heterojunction photodetector exhibits a response bandwidth of~1.0 GHz and a uniform photodetection over a wide spectral range,as experimentally measured from 1500 to 1630 nm.The demonstrated chip-integrated van der Waals PN heterojunction photodetector with low dark current,high responsivity and fast response has great potentials to develop high-performance on-chip photodetectors for various photonic integrated circuits based on silicon,lithium niobate,polymer,etc.
文摘By combining ab initio calculations and experiments, we demonstrate how the band gap of the transition metal trichalcogenide TiS3 can be modified by inducing tensile or compressive strain. In addition, using our calculations, we predicted that the material would exhibit a transition from a direct to an indirect band gap upon application of a compressive strain in the direction of easy electrical transport. The ability to control the band gap and its nature could have a significant impact on the use of TiS3 for optical applications. We go on to verify our prediction via optical absorption experiments that demonstrate a band gap increase of up to 9% （from 0.99 to 1.08 eV） upon application of tensile stress along the easy transport direction.
文摘We propose a realistic topological p-n junction （TPNJ） by matching two Bi2Se3 （0001） slabs with opposite arrangements of planar twin boundary defects. The atomistic modeling of such a device leads to dislocation defects in the hexagonal lattice in several quintuple layers. Nevertheless, total energy calculations reveal that the interface relaxes, yielding a smooth geometrical transition that preserves the nearest-neighbors fcc-type geometry throughout these defect layers. The electronic, magnetic, and transport properties of the junction have then been calculated at the ab initio level under open boundary conditions, i.e., employing a thin-film geometry that is infinite along the electron transport direction. Indeed, a p-n junction is obtained with a built-in potential as large as 350 meV. The calculations further reveal the spin texture across the interface with unprecedented detail. As the main result, we obtain non-negligible transmission probabilities around the F point, which involve an electron spin-flip process while crossing the interface.
文摘Cl-functionalized scanning tunneling microscopy （STM） tips are fabricated by modifying a tungsten STM tip in situ on islands of ultrathin NaCI（100） films on Au（111） surfaces. The functionalized tips are used to achieve clear atomic- resolution imaging of NaCI（100） islands. In comparison with bare metal tips, the chemically modified tips yield drastically enhanced spatial resolution as well as contrast reversal in STM topographs, implying that Na atoms, rather than C1 atoms, are imaged as protrusions. STM simulations based on a Green＇s function formalism reveal that the experimentally observed contrast reversal in the STM topographs is due to the highly localized character of the Cl-pz states at the tip apex. An additional remarkable characteristic of the modified tips is that in dI/dV maps, a Na atom appears as a ring with a diameter that depends crucially on the tip-sample distance.
基金The research leading to these results has received funding from the ERC under the EC’s Seventh Framework Program(FP7/2007-2013)grant agreement n.201766,EU FP7 NoE Nanophotonics4Enery Grant No.248855the Spanish MICINN CSD2007-0046(Nanolight.es)+1 种基金MAT2009-07841(GLUSFA)and Comunidad de Madrid S2009/MAT2012-31659.
文摘Random lasing is observed in optically active resonators in the presence of disorder.As the optical cavities involved are open,the modes are coupled,and energy may pour from one state to another provided that they are spatially overlapping.Although the electromagnetic modes are spatially localized,our system may be actively switched to a collective state,presenting a novel form of non-locality revealed by a high degree of spectral correlation between the light emissions collected at distant positions.In a nutshell,light may be stored in a disordered nonlinear structure in different fashions that strongly differ in their spatial properties.This effect is experimentally demonstrated and theoretically explained in titania clusters embedded in a dye,and it provides clear evidence of a transition to a multimodal collective emission involving the entire spatial extent of the disordered system.Our results can be used to develop a novel type of miniaturized,actively controlled all-optical chip.
