The enhanced carrier flow at the interface between Au and SnO_(2)semiconductors,which initially form Schottky contacts,is realized using chloride-based combustion synthesis.Chloride-based combustion sys-tems can achie...The enhanced carrier flow at the interface between Au and SnO_(2)semiconductors,which initially form Schottky contacts,is realized using chloride-based combustion synthesis.Chloride-based combustion sys-tems can achieve chlorine(Cl)doping effects as well as conversion to crystalline SnO_(2)films at clearly lower temperatures(∼250℃)than conventional precursors.Due to the Cl doping effect,the high carrier concentration can induce thin potential barriers at the metal/semiconductor(MS)junctions,resulting in carrier injection by tunneling.As a result,compared to conventional SnO_(2)thin-film transistors,the de-vices fabricated by combustion synthesis exhibit significantly improved electrical performance with field-effect mobility of 6.52 cm 2/Vs(∼13 times),subthreshold swing of 0.74 V/dec,and on/offratio of∼10^(7)below 300℃.Furthermore,because of the enhanced tunneling carriers induced by the narrowed barrier width,the Schottky barriers are significantly reduced from 0.83 to 0.29 eV(65%decrease)at 250℃and from 0.42 to 0.17 eV(60%decrease)at 400℃.Therefore,chloride-based combustion synthesis can con-tribute to developing SnO_(2)-based electronics and flexible devices by achieving both high-quality oxide films and improved current flow at the MS interface with low-temperature annealing.展开更多
Transparent electro-optical neural interfacing technologies offer simultaneous high-spatial-resolution microscopic imaging,and high-temporal-resolution electrical recording and stimulation.However,fabricating transpar...Transparent electro-optical neural interfacing technologies offer simultaneous high-spatial-resolution microscopic imaging,and high-temporal-resolution electrical recording and stimulation.However,fabricating transparent,flexible,and mechanically robust neural electrodes with high electrochemical performance remains challenging.In this study,we fabricated transparent(72.7%at 570 nm),mechanically robust(0.05%resistance change after 50k bending cycles)ultrathin Au microelectrodes for micro-electrocorticography(µECoG)using a hexadentate metal-polymer ligand bonding with an EDTA/PSS seed layer.These transparentµECoG arrays,fabricated with biocompatible gold,exhibit excellent electrochemical properties(0.73Ω·cm^(2))for neural recording and stimulation with long-term stability.We recorded brain surface waves in vivo,maintaining a low baseline noise and a high signalto-noise ratio during acute and two-week recordings.In addition,we successfully performed optogenetic modulation without light-induced artifacts at 7.32 mW/mm^(2)laser power density.This approach shows great potential for scalable,implantable neural electrodes and wearable optoelectronic devices in digital healthcare systems.展开更多
Bulk photovoltaic effect,characterized by an excitation-driven unbiased spontaneous photocurrent,has attracted substantial attention mainly due to its potential for harvesting solar energy.Here,we investigate the phot...Bulk photovoltaic effect,characterized by an excitation-driven unbiased spontaneous photocurrent,has attracted substantial attention mainly due to its potential for harvesting solar energy.Here,we investigate the photovoltaic characteristics of organic molecular solids and focus on the association between the photocurrent and the crystal symmetry in the exemplary case of tetrathiafulvalene-p-chloranil.We perform comprehensive first-principles calculations,including direct evaluations of the excitedstate current via real-time propagations of the time-dependent density functional theory.We find that the charge shifting in the low-temperature phase is mainly driven by the intrachain ferroelectricity,which gives rise to a photocurrent not only in the visiblelight range but also near the band-edge infrared region.The shift current that is locked in the symmetry of the high-temperature phase can be released by introducing a potential asymmetry.We suggest that organic molecular solids can be exploited via appropriate engineering to lower the symmetry,aiming at room-temperature photovoltaics.展开更多
基金supported by the DGIST R&D Program of the Ministry of Science and ICT(Nos.23-CoE-BT-03 and 23-IJRP-01)supported by the Basic Science Research Pro-gram through the National Research Foundation of Korea(NRF)funded by the MSIT(No.2019M3C1B8090840)by the Ministry of Education(No.2020R1A6A1A03040516).
文摘The enhanced carrier flow at the interface between Au and SnO_(2)semiconductors,which initially form Schottky contacts,is realized using chloride-based combustion synthesis.Chloride-based combustion sys-tems can achieve chlorine(Cl)doping effects as well as conversion to crystalline SnO_(2)films at clearly lower temperatures(∼250℃)than conventional precursors.Due to the Cl doping effect,the high carrier concentration can induce thin potential barriers at the metal/semiconductor(MS)junctions,resulting in carrier injection by tunneling.As a result,compared to conventional SnO_(2)thin-film transistors,the de-vices fabricated by combustion synthesis exhibit significantly improved electrical performance with field-effect mobility of 6.52 cm 2/Vs(∼13 times),subthreshold swing of 0.74 V/dec,and on/offratio of∼10^(7)below 300℃.Furthermore,because of the enhanced tunneling carriers induced by the narrowed barrier width,the Schottky barriers are significantly reduced from 0.83 to 0.29 eV(65%decrease)at 250℃and from 0.42 to 0.17 eV(60%decrease)at 400℃.Therefore,chloride-based combustion synthesis can con-tribute to developing SnO_(2)-based electronics and flexible devices by achieving both high-quality oxide films and improved current flow at the MS interface with low-temperature annealing.
基金supported in part by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.RS-2022-NR069917,RS-2024-00416319)in part by the‘DGIST intramural grant’(25-IRJoint-03)+1 种基金in part by an Ideas Grant from the National Health and Medical Research Council(NHMRC)of Australia(APP1188414)in part by the Interdisciplinary Research Initiatives Program from College of Engineering and College of Medicine,Seoul National University(grant no.800-20240490).
文摘Transparent electro-optical neural interfacing technologies offer simultaneous high-spatial-resolution microscopic imaging,and high-temporal-resolution electrical recording and stimulation.However,fabricating transparent,flexible,and mechanically robust neural electrodes with high electrochemical performance remains challenging.In this study,we fabricated transparent(72.7%at 570 nm),mechanically robust(0.05%resistance change after 50k bending cycles)ultrathin Au microelectrodes for micro-electrocorticography(µECoG)using a hexadentate metal-polymer ligand bonding with an EDTA/PSS seed layer.These transparentµECoG arrays,fabricated with biocompatible gold,exhibit excellent electrochemical properties(0.73Ω·cm^(2))for neural recording and stimulation with long-term stability.We recorded brain surface waves in vivo,maintaining a low baseline noise and a high signalto-noise ratio during acute and two-week recordings.In addition,we successfully performed optogenetic modulation without light-induced artifacts at 7.32 mW/mm^(2)laser power density.This approach shows great potential for scalable,implantable neural electrodes and wearable optoelectronic devices in digital healthcare systems.
基金B.K.,D.S.,M.C.,J.L.and N.P.acknowledge support from the National Research Foundation of Korea(NRF)through the Basic Research Laboratory(NRF-2017R1A4A1015323)J.K.was supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.2019R1F1A1059743)+1 种基金This work was supported by the National Supercomputing Center with supercomputing resources including technical support(KSC-2019-CRE-0035)This work was supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.NRF-2019R1A2C2089332).
文摘Bulk photovoltaic effect,characterized by an excitation-driven unbiased spontaneous photocurrent,has attracted substantial attention mainly due to its potential for harvesting solar energy.Here,we investigate the photovoltaic characteristics of organic molecular solids and focus on the association between the photocurrent and the crystal symmetry in the exemplary case of tetrathiafulvalene-p-chloranil.We perform comprehensive first-principles calculations,including direct evaluations of the excitedstate current via real-time propagations of the time-dependent density functional theory.We find that the charge shifting in the low-temperature phase is mainly driven by the intrachain ferroelectricity,which gives rise to a photocurrent not only in the visiblelight range but also near the band-edge infrared region.The shift current that is locked in the symmetry of the high-temperature phase can be released by introducing a potential asymmetry.We suggest that organic molecular solids can be exploited via appropriate engineering to lower the symmetry,aiming at room-temperature photovoltaics.
