The early determination of disease-related biomarkers can significantly improve the survival rate of patients.Thus,a series of explorations for new diagnosis technologies,such as optical and electrochemical methods,ha...The early determination of disease-related biomarkers can significantly improve the survival rate of patients.Thus,a series of explorations for new diagnosis technologies,such as optical and electrochemical methods,have been devoted to life and health monitoring.Organic thin-film transistor(OTFT),as a state-of-the-art nano-sensing technology,has attracted significant attention from construction to application owing to the merits of being label-free,low-cost,facial,and rapid detection with multi-parameter responses.Nevertheless,interference from non-specific adsorption is inevitable in complex biological samples such as body liquid and exhaled gas,so the reliability and accuracy of the biosensor need to be further improved while ensuring sensitivity,selectivity,and stability.Herein,we overviewed the composition,mechanism,and construction strategies of OTFTs for the practical determination of disease-related biomarkers in both body fluids and exhaled gas.The results show that the realization of bio-inspired applications will come true with the rapid development of high-effective OTFTs and related devices.展开更多
The solubility of a direct arylation polycondensation(DArP)synthesized conjugated polymer,i.e.,poly(3,6-bis(furan-2-yl)-2,5-bis(4-tetradecyloctadecyl)-pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-alt-1,2-bis(3,4-d ifl uorot...The solubility of a direct arylation polycondensation(DArP)synthesized conjugated polymer,i.e.,poly(3,6-bis(furan-2-yl)-2,5-bis(4-tetradecyloctadecyl)-pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-alt-1,2-bis(3,4-d ifl uorothien-2-yl)ethene)(PFuD PP-4FTVT),in variou s organic solvents was studied.The polymer is soluble in 3-methylcyclohexanone(3-MC),a green solvent from peppermint oil,besides other solvents such as anisole,cyclopentyl methyl ether(CPME)and o-dichlorobenzene(o-DCB),etc.Based on the Hansen solu bility parameters(HSP)analysis,3-MC is identified as a"marginal solvent"of PFuDPP-4FTVT.The morphology of the spin-coated films with 3-MC as the solvent strongly correlated with the solution preparation conditions.With a 3-MC solution aged for 3 h at 70℃,n-channel organic thin-film transistors(OTFTs)with electron mobility(μe)above 1 cm^(2)·V^(-1)·s^(-1) and current on/off ratio(Ion/Ioff)higher than 105 were fabricated by spin-coating.This is the first report on high mobility conjugated polymers for OTFTs processible with natu rally occurred green solvent.展开更多
Since the first report of diketopyrrolopyrrole(DPP)-based conjugated polymers for organic thin-film transistors(OTFTs),these polymers have attracted great attention as representative semiconductors in high-performance...Since the first report of diketopyrrolopyrrole(DPP)-based conjugated polymers for organic thin-film transistors(OTFTs),these polymers have attracted great attention as representative semiconductors in high-performance OTFTs.Through unremitting efforts in molecular-structure regulation and device optimization,significant mobilities exceeding 10 cm2·V–1·s–1 have been achieved in OTFTs,greatly promoting the applied development of organic circuits.In this review,we summarize our progress in molecular design,synthesis and solution-processing of DPP-based conjugated polymers for OTFT devices and circuits,focusing on the roles of design strategies,synthesis methods and processing techniques.Furthermore,the remaining issues and future outlook in the field are briefly discussed.展开更多
Advanced organic devices and circuits demand both ultrahigh charge carrier mobilities and ultralow-resistance contacts.However,due to a larger access resistance in staggered organic thin-film transistors(OTFTs),the ac...Advanced organic devices and circuits demand both ultrahigh charge carrier mobilities and ultralow-resistance contacts.However,due to a larger access resistance in staggered organic thin-film transistors(OTFTs),the achievement of ultralow contact resistance(Rc)is still a challenge.The modulation of contact resistance by molecular layers near the interface has been rarely reported.Here,we demonstrate that fewlayer organic single crystals are grown on hafnium oxide(HfO_(2))by solution-shearing epitaxy.We utilize these organic crystals to fabricate bottom-gate staggered OTFTs with different contact processes.The results show that the contact properties of OTFTs are obviously modulated by crystal layers.The tri-layer(3L)evaporated-Au C10-DNTT OTFTs exhibit optimal electrical performance,including ultralow Rc of 5.6Ω⋅cm,recorded transfer length of 0.4μm,field-effect mobility over 14 cm^(2)V^(−1)s^(−1),threshold voltage lower than 0.3 V,and long-term air stability over 8 months.The main cause is that the metal atoms can penetrate into the charge transport layer,with damage-free,in 3L evaporated-Au OTFTs;nevertheless,it cannot be realized in other cases.Due to layer stacking of conjugated molecules and polymers,our strategy can efficiently modulate the contact resistance to aid the development of highperformance organic devices and circuits.展开更多
Chlorinated conjugated polymers are rarely reported in ambipolar and n-type organic thin-film transistors(OTFTs),mainly due to the lack of chlorinated strong electron-deficient building blocks.Herein,we report three n...Chlorinated conjugated polymers are rarely reported in ambipolar and n-type organic thin-film transistors(OTFTs),mainly due to the lack of chlorinated strong electron-deficient building blocks.Herein,we report three new chlorine(Cl)-and cyano(CN)-substituted(E)-1,2-di(thiophen-2-yl)ethane building blocks and their copolymers P2Cl1CNTVT-DPP,P4Cl1CNTVT-DPP and P2Cl2CNTVT-DPP.展开更多
Three acceptor-donor-acceptor (A-D-A) conjugated oligomers, i.e., O1, 02 and 03, have been synthesized using diketopyrrolopyrrole (DPP) as an electron-acceptor unit, and naphtho[1,2-b:5,6-b']dithiophene (NDT),...Three acceptor-donor-acceptor (A-D-A) conjugated oligomers, i.e., O1, 02 and 03, have been synthesized using diketopyrrolopyrrole (DPP) as an electron-acceptor unit, and naphtho[1,2-b:5,6-b']dithiophene (NDT), anthra[1,2-b:5,6- b']dithiophene (ADT) or dithieno[3,2-b:Y,2'-b']naphtbo[1,2-b:5,6-b']dithiophene (DTNDT) as electron-donor unit. These oligomers exhibit identical highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels, which were ca. -5.1 and -3.3 eV, respectively. Upon thermal annealing, all three oligomers formed thin films with ordered microstructures, and their organic thin film transistors (OTFTs) exhibited p-type transport behavior. The mobility was increased with an extension of the size of D-units. 03 showed the best OTFT performance with the mobility of up to 0.20 cm2·V-1 ·s-1. The film quality of 03 was improved by adding 1 wt% poly(methylmethacrylate) (PMMA). In consequence, the mobility of the O3-based devices was further enhanced to 0.30 cm2·V-1 ·s-1.展开更多
Balanced carrier transport is observed in acceptor-acceptor (A-A′) type polymer for ambipolar organic thin-film transistors B (OTFTs). It is found that the incorporation of two electron-accepting moieties (BTz and II...Balanced carrier transport is observed in acceptor-acceptor (A-A′) type polymer for ambipolar organic thin-film transistors B (OTFTs). It is found that the incorporation of two electron-accepting moieties (BTz and IIG) into a polymer main chain to form A-A′ polymer PIIG-BTz could lower highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels and facilitate good molecular stacking of the polymer. Ambipolar transistor behaviour for PIIG-BTz, with the balanced hole and electron mobilities of 0.030 and 0.022 cm2 V-1 s-1 was observed in OTFT devices, respectively. The study in this work reveals that the utilization of acceptor-acceptor (A-A′) structure in polymer main chain can be a feasible strategy to develop ambipolar polymer semiconductors.展开更多
As growing applications demand higher driving currents of oxide semiconductor thin-film transistors(TFTs),severe instabilities and even hard breakdown under high-current stress(HCS)become critical challenges.In this w...As growing applications demand higher driving currents of oxide semiconductor thin-film transistors(TFTs),severe instabilities and even hard breakdown under high-current stress(HCS)become critical challenges.In this work,the triggering voltage of HCS-induced self-heating(SH)degradation is defined in the output characteristics of amorphous indium-galliumzinc oxide(a-IGZO)TFTs,and used to quantitatively evaluate the thermal generation process of channel donor defects.The fluorinated a-IGZO(a-IGZO:F)was adopted to effectively retard the triggering of the self-heating(SH)effect,and was supposed to originate from the less population of initial deep-state defects and a slower rate of thermal defect transition in a-IGZO:F.The proposed scheme noticeably enhances the high-current applications of oxide TFTs.展开更多
Indium-tin-zinc oxide(ITZO)thin-film transistor(TFT)technology holds promise for achieving high mobility and offers significant opportunities for commercialization.This paper provides a review of progress made in impr...Indium-tin-zinc oxide(ITZO)thin-film transistor(TFT)technology holds promise for achieving high mobility and offers significant opportunities for commercialization.This paper provides a review of progress made in improving the mobility of ITZO TFTs.This paper begins by describing the development and current status of metal-oxide TFTs,and then goes on to explain the advantages of selecting ITZO as the TFT channel layer.The evaluation criteria for TFTs are subsequently introduced,and the reasons and significance of enhancing mobility are clarified.This paper then explores the development of high-mobility ITZO TFTs from five perspectives:active layer optimization,gate dielectric optimization,electrode optimization,interface optimization,and device structure optimization.Finally,a summary and outlook of the research field are presented.展开更多
Fabrication of ambipolar organic field-effect transistors (OFETs) is essential for the achievement of an organic complementary logic circuit. Ambipolar transports in OFETs with heterojunction structures are realized...Fabrication of ambipolar organic field-effect transistors (OFETs) is essential for the achievement of an organic complementary logic circuit. Ambipolar transports in OFETs with heterojunction structures are realized.We select pentacene as a P-type material and N,N'-bis(4-trifluoromethylben-zyl)perylene-3,4,9,10-tetracarboxylic diimide (PTCDI-TFB) as a n-type material in the active layer of the OFETs.The field-effect transistor shows highly air-stable ambipolar characteristics with a field-effect hole mobility of 0.18 cm^2/(V·s) and field-effect electron mobility of 0.031 cm^2/(V·s).Furthermore the mobility only slightly decreases after being exposed to air and remains stable even for exposure to air for more than 60 days.The high electron affinity of PTCDI-TFB and the octadecyltrichlorosilane (OTS) self-assembly monolayer between the SiO2 gate dielectric and the organic active layer result in the observed air-stable characteristics of OFETs with high mobility.The results demonstrate that using the OTS as a modified gate insulator layer and using high electron affinity semiconductor materials are two effective methods to fabricate OFETs with air-stable characteristics and high mobility.展开更多
Organic field-effect transistors(OFETs) based on organic micro-/nanocrystals have been widely reported with charge carrier mobility exceeding 1.0 cm^2V^(-1)s^(-1), demonstrating great potential for high-performance, l...Organic field-effect transistors(OFETs) based on organic micro-/nanocrystals have been widely reported with charge carrier mobility exceeding 1.0 cm^2V^(-1)s^(-1), demonstrating great potential for high-performance, low-cost organic electronic applications. However, fabrication of large-area organic micro-/nanocrystal arrays with consistent crystal growth direction has posed a significant technical challenge. Here, we describe a solution-processed dip-coating technique to grow large-area, aligned 9,10-bis(phenylethynyl) anthracene(BPEA) and 6,13-bis(triisopropylsilylethynyl) pentacene(TIPSPEN) single-crystalline nanoribbon arrays. The method is scalable to a 5 9 10 cm^2 wafer substrate, with around 60% of the wafer surface covered by aligned crystals. The quality of crystals can be easily controlled by tuning the dip-coating speed. Furthermore, OFETs based on well-aligned BPEA and TIPS-PEN single-crystalline nanoribbons were constructed.By optimizing channel lengths and using appropriate metallic electrodes, the BPEA and TIPS-PEN-based OFETs showed hole mobility exceeding 2.0 cm^2V^(-1)s^(-1)(average mobility 1.2 cm^2V^(-1)s^(-1)) and 3.0 cm^2V^(-1)s^(-1)(average mobility2.0 cm^2V^(-1)s^(-1)), respectively. They both have a high on/off ratio(I_(on)/I_(off))>10~9. The performance can well satisfy the requirements for light-emitting diodes driving.展开更多
Pentacene organic field-effect transistors (OFETs) based on single- or double-layer biocompatible dielectrics of poly(methyl methacrylate) (PMMA) and/or silk fibroin (SF) are fabricated. Compared with those de...Pentacene organic field-effect transistors (OFETs) based on single- or double-layer biocompatible dielectrics of poly(methyl methacrylate) (PMMA) and/or silk fibroin (SF) are fabricated. Compared with those devices based on sin- gle PMMA or SF dielectric or SF/PMMA bilayer dielectric, the OFETs with biocompatible PMMA/SF bilayer dielectric exhibit optimal performance with a high field-effect mobility of 0.21 cm2/Vs and a current on/off ratio of 1.5 × 104. By investigating the surface morphology of the pentacene active layer through atom force microscopy and analyzing the elec- trical properties, the performance enhancement is mainly attributed to the crystallization improvement of the pentacene and the smaller interface trap density at the dielectric/organic interface. Meanwhile, a low contact resistance also indicates that a good electrode/organic contact is formed, thereby assisting the performance improvement of the OFET.展开更多
The properties of top-contact organic thin-film transistors (TC-OTFTs) using ultra-thin 2, 9-dimethyl-4, 7- diphenyl-1, 10-phenanthroline (BCP) as a hole-blocking interlayer have been improved significantly and a ...The properties of top-contact organic thin-film transistors (TC-OTFTs) using ultra-thin 2, 9-dimethyl-4, 7- diphenyl-1, 10-phenanthroline (BCP) as a hole-blocking interlayer have been improved significantly and a BCP interlayer was inserted into the middle of the pentacene active layer. This paper obtains a fire-new transport mode of an OTFT device with double-conductible channels. The accumulation and transfer of the hole carriers arc limited by the BCP interlayer in the vertical region of the channel. A huge amount of carriers is located not only at the interface between pentacene and the gate insulator, but also at the two interfaces of pentacene/BCP interlayer and pentacene/gate insulator, respectively. The results suggest that the BCP interlayer may be useful to adjust the hole accumulation and transfer, and can increase the hole mobility and output current of OTFTs. The TC-OTFTs with a BCP interlayer at VDS = --20 V showed excellent hole mobility μFE and threshold voltage VTH of 0.58 cm^2/(V-s) and -4.6 V, respectively.展开更多
In this article, an organic thin-film field-effect transistor (OTFFET) with top-gate and bottom-contact geometry based on pentacene as the active layer is fabricated. The experimental data of the I-V are obtained fr...In this article, an organic thin-film field-effect transistor (OTFFET) with top-gate and bottom-contact geometry based on pentacene as the active layer is fabricated. The experimental data of the I-V are obtained from the OTFFET device. The alternating-current (AC) resistance value of the OTFFET device is calculated using the derivation method from the experimental data, and the AC resistance trend curves of the OTFFET device are obtained with the region fitting method. We analyse the characteristics of the OTFFET device with an AC resistance trend curve. To discover whether it has a high resistance, it is proposed to judge the region of the source/drain voltage (VDs) less than the transition voltage, thereby determining whether the contact between the metal electrode and the organic semiconductor layer of the OTFFET device is Ohmic or non-Ohmic. The theoretical analysis shows that the field-effect mobility and the AC resistance are in reverse proportion. Therefore, we point out that reducing AC resistance is necessary if field-effect mobility is to be improved.展开更多
With the aim of understanding the relationships between organic small molecule field-effect transistors (FETs) and organic conjugated polymer FETs, we investigate the thickness dependence of surface morphology and c...With the aim of understanding the relationships between organic small molecule field-effect transistors (FETs) and organic conjugated polymer FETs, we investigate the thickness dependence of surface morphology and charge carrier mobility in pentacene and regioregular poly (3-hexylthiophene) (RR-P3HT) field-effect transistors. On the basis of the results of surface morphologies and electrical properties, we presume that the charge carrier mobility is largely related to the morphology of the organic active layer. We observe that the change trends of the surface morphologies (average size and average roughness) of pentacene and RR-P3HT thin films are mutually opposite, as the thickness of the organic layer increases. Further, we demonstrate that the change trends of the field-effect mobilities of pentacene and RR-P3HT FETs are also opposite to each other, as the thickness of the organic layer increases within its limit.展开更多
InGaAs high electron mobility transistors(HEMTs)on InP substrate with very good device performance have been grown by mental organic chemical vapor deposition(MOCVD).Room temperature Hall mobilities of the 2-DEG are m...InGaAs high electron mobility transistors(HEMTs)on InP substrate with very good device performance have been grown by mental organic chemical vapor deposition(MOCVD).Room temperature Hall mobilities of the 2-DEG are measured to be over 8700cm2/V-s with sheet carrier densities larger than 4.6×10 12cm-2.Transistors with 1.0μm gate length exhibits transconductance up to 842mS/mm.Excellent depletion-mode operation,with a threshold voltage of-0.3V and IDSS of 673mA/mm,is realized.The non-alloyed ohmic contact special resistance is as low as 1.66×10-8Ω/cm2,which is so far the lowest ohmic contact special resistance.The unity current gain cut off frequency(fT)and the maximum oscillation frequency(fmax)are 42.7 and 61.3 GHz,respectively.These results are very encouraging toward manufacturing InP-based HEMT by MOCVD.展开更多
This paper proposes an effective method of fabricating top contact organic field effect transistors by using a pho- tolithographic process. The semiconductor layer is protected by a passivation layer. Through photolit...This paper proposes an effective method of fabricating top contact organic field effect transistors by using a pho- tolithographic process. The semiconductor layer is protected by a passivation layer. Through photolithographic and etching processes, parts of the passivation layer are etched off to form source/drain electrode patterns. Combined with conventional evaporation and lift-off techniques, organic field effect transistors with a top contact are fabricated suc- cessfully, whose properties are comparable to those prepared with the shadow mask method and one order of magnitude higher than the bottom contact devices fabricated by using a photolithographic process.展开更多
The contact effect on the performances of organic thin film transistors is studied here. A C60 ultrathin layer is inserted between Al source-drain electrode and pentacene to reduce the contact resistance. By a 3 nm C6...The contact effect on the performances of organic thin film transistors is studied here. A C60 ultrathin layer is inserted between Al source-drain electrode and pentacene to reduce the contact resistance. By a 3 nm C60 modification, the injection barrier is lowered and the contact resistance is reduced. Thus, the field-effect mobility increases from 0.12 to 0.52 cm2/(V.s). It means that inserting a C60 ultra thin layer is a good method to improve the organic thin film transistor (OTFT) performance. The output curve is simulated by using a charge drift model. Considering the contact effect, the field effect mobility is improved to 1.15 cm2/(V-s). It indicates that further reducing the contact resistance of OTFTs should be carried out.展开更多
Organic ferroelectric field-effect transistors (OFeFETs) are regarded as a promising technology for low-cost flexible memories. However, the electrical instability is still a critical obstacle, which limits the comm...Organic ferroelectric field-effect transistors (OFeFETs) are regarded as a promising technology for low-cost flexible memories. However, the electrical instability is still a critical obstacle, which limits the commercialization process. Based on already established models for polarization in ferroelectrics and charge transport in OFeFETs, simulation work is performed to determine the influence of polarization fatigue and ferroelectric switching transient on electrical characteristics in OFeFETs. The polarization fatigue results in the decrease of the on-state drain current and the memory window width and thus degrades the memory performance. The output measurements during the ferroelectric switching process show a hysteresis due to the instable polarization. In the on/off measurements, a large writing/erasing pulse frequency weakens the polarization modulation and thus results in a small separation between on- and off-state drain currents. According to the electrical properties of the ferroelectric layer, suggestions are given to obtain optimal electrical characterization for OFeFETs.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21925405,22104141,22104142,22004122,and 201874005)the National Key Research and Development Program of China Grant(Nos.2018YFA0208800 and 2021YFD1700300)+1 种基金the Chinese Academy of Sciences(Nos.XDA23030106 and YJKYYQ20180044)the China Postdoctoral Science Foundation(Nos.2020M680676 and 2021T140680).
文摘The early determination of disease-related biomarkers can significantly improve the survival rate of patients.Thus,a series of explorations for new diagnosis technologies,such as optical and electrochemical methods,have been devoted to life and health monitoring.Organic thin-film transistor(OTFT),as a state-of-the-art nano-sensing technology,has attracted significant attention from construction to application owing to the merits of being label-free,low-cost,facial,and rapid detection with multi-parameter responses.Nevertheless,interference from non-specific adsorption is inevitable in complex biological samples such as body liquid and exhaled gas,so the reliability and accuracy of the biosensor need to be further improved while ensuring sensitivity,selectivity,and stability.Herein,we overviewed the composition,mechanism,and construction strategies of OTFTs for the practical determination of disease-related biomarkers in both body fluids and exhaled gas.The results show that the realization of bio-inspired applications will come true with the rapid development of high-effective OTFTs and related devices.
基金financially supported by the National Natural Science Foundation of China(Nos.51933008 and 52121002)the Fundamental Research Funds for the Central Universities。
文摘The solubility of a direct arylation polycondensation(DArP)synthesized conjugated polymer,i.e.,poly(3,6-bis(furan-2-yl)-2,5-bis(4-tetradecyloctadecyl)-pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-alt-1,2-bis(3,4-d ifl uorothien-2-yl)ethene)(PFuD PP-4FTVT),in variou s organic solvents was studied.The polymer is soluble in 3-methylcyclohexanone(3-MC),a green solvent from peppermint oil,besides other solvents such as anisole,cyclopentyl methyl ether(CPME)and o-dichlorobenzene(o-DCB),etc.Based on the Hansen solu bility parameters(HSP)analysis,3-MC is identified as a"marginal solvent"of PFuDPP-4FTVT.The morphology of the spin-coated films with 3-MC as the solvent strongly correlated with the solution preparation conditions.With a 3-MC solution aged for 3 h at 70℃,n-channel organic thin-film transistors(OTFTs)with electron mobility(μe)above 1 cm^(2)·V^(-1)·s^(-1) and current on/off ratio(Ion/Ioff)higher than 105 were fabricated by spin-coating.This is the first report on high mobility conjugated polymers for OTFTs processible with natu rally occurred green solvent.
基金financially supported by the National Key R&D Program of China(No.2018YFA0703200)the National Natural Science Foundation of China(Nos.U22A6002,91833306,21922511 and 51873216)+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB30000000)the CAS Project for Young Scientists in Basic Research(No.YSBR-053)the CAS-Croucher Funding Scheme for Joint Laboratoriesthe CAS Cooperation Project(No.121111KYSB20200036)。
文摘Since the first report of diketopyrrolopyrrole(DPP)-based conjugated polymers for organic thin-film transistors(OTFTs),these polymers have attracted great attention as representative semiconductors in high-performance OTFTs.Through unremitting efforts in molecular-structure regulation and device optimization,significant mobilities exceeding 10 cm2·V–1·s–1 have been achieved in OTFTs,greatly promoting the applied development of organic circuits.In this review,we summarize our progress in molecular design,synthesis and solution-processing of DPP-based conjugated polymers for OTFT devices and circuits,focusing on the roles of design strategies,synthesis methods and processing techniques.Furthermore,the remaining issues and future outlook in the field are briefly discussed.
基金National Natural Science Foundation of China,Grant/Award Numbers:62074076,61927808,61734003,91964202,51861145202National Key R&D Program of China,Grant/Award Numbers:2021YFA1202903,2021YFA0715600,2021YFA1202903,and 2018YFB2200500+4 种基金Leading-edge Technology Program of Jiangsu Natural Science Foundation,Grant/Award Number:BK20202005Key Lab of Optoelectronic Devices and Systems with Extreme PerformancesCollaborative Innovation Center of Solid-State Lighting and Energy-Saving ElectronicsChina Postdoctoral Science Foundation,Grant/Award Number:2022M711564China National Postdoctoral Program for Innovative Talents,Grant/Award Number:BX2021119。
文摘Advanced organic devices and circuits demand both ultrahigh charge carrier mobilities and ultralow-resistance contacts.However,due to a larger access resistance in staggered organic thin-film transistors(OTFTs),the achievement of ultralow contact resistance(Rc)is still a challenge.The modulation of contact resistance by molecular layers near the interface has been rarely reported.Here,we demonstrate that fewlayer organic single crystals are grown on hafnium oxide(HfO_(2))by solution-shearing epitaxy.We utilize these organic crystals to fabricate bottom-gate staggered OTFTs with different contact processes.The results show that the contact properties of OTFTs are obviously modulated by crystal layers.The tri-layer(3L)evaporated-Au C10-DNTT OTFTs exhibit optimal electrical performance,including ultralow Rc of 5.6Ω⋅cm,recorded transfer length of 0.4μm,field-effect mobility over 14 cm^(2)V^(−1)s^(−1),threshold voltage lower than 0.3 V,and long-term air stability over 8 months.The main cause is that the metal atoms can penetrate into the charge transport layer,with damage-free,in 3L evaporated-Au OTFTs;nevertheless,it cannot be realized in other cases.Due to layer stacking of conjugated molecules and polymers,our strategy can efficiently modulate the contact resistance to aid the development of highperformance organic devices and circuits.
基金the National Key Research and Development Program(No.2018YFA0703200)the National Natural Science Foundation of China(No.21975176)。
文摘Chlorinated conjugated polymers are rarely reported in ambipolar and n-type organic thin-film transistors(OTFTs),mainly due to the lack of chlorinated strong electron-deficient building blocks.Herein,we report three new chlorine(Cl)-and cyano(CN)-substituted(E)-1,2-di(thiophen-2-yl)ethane building blocks and their copolymers P2Cl1CNTVT-DPP,P4Cl1CNTVT-DPP and P2Cl2CNTVT-DPP.
基金financially supported by National Basic Research Program of China(973 Program,No.2014CB643504)of Chinese Ministry of Science and Technologythe National Natural Science Foundation of China(No.51333006)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB12010300)
文摘Three acceptor-donor-acceptor (A-D-A) conjugated oligomers, i.e., O1, 02 and 03, have been synthesized using diketopyrrolopyrrole (DPP) as an electron-acceptor unit, and naphtho[1,2-b:5,6-b']dithiophene (NDT), anthra[1,2-b:5,6- b']dithiophene (ADT) or dithieno[3,2-b:Y,2'-b']naphtbo[1,2-b:5,6-b']dithiophene (DTNDT) as electron-donor unit. These oligomers exhibit identical highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels, which were ca. -5.1 and -3.3 eV, respectively. Upon thermal annealing, all three oligomers formed thin films with ordered microstructures, and their organic thin film transistors (OTFTs) exhibited p-type transport behavior. The mobility was increased with an extension of the size of D-units. 03 showed the best OTFT performance with the mobility of up to 0.20 cm2·V-1 ·s-1. The film quality of 03 was improved by adding 1 wt% poly(methylmethacrylate) (PMMA). In consequence, the mobility of the O3-based devices was further enhanced to 0.30 cm2·V-1 ·s-1.
基金supported by the National Natural Science Foundation of China (51173055, 21504026, 51572094)the National Basic Research Program of China (2013CBA01600)the China Postdoctoral Science Foundation (2013M542009)
文摘Balanced carrier transport is observed in acceptor-acceptor (A-A′) type polymer for ambipolar organic thin-film transistors B (OTFTs). It is found that the incorporation of two electron-accepting moieties (BTz and IIG) into a polymer main chain to form A-A′ polymer PIIG-BTz could lower highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels and facilitate good molecular stacking of the polymer. Ambipolar transistor behaviour for PIIG-BTz, with the balanced hole and electron mobilities of 0.030 and 0.022 cm2 V-1 s-1 was observed in OTFT devices, respectively. The study in this work reveals that the utilization of acceptor-acceptor (A-A′) structure in polymer main chain can be a feasible strategy to develop ambipolar polymer semiconductors.
基金supported by National Key Research and Development Program under Grant No.2022YFB3607100Shenzhen Research Programs under Grant Nos.JCYJ20200109140601691,JCYJ20190808154803565,SGDX20201103095607022,SGDX20211123145404006,and GXWD20201231165807007-20200807025846001。
文摘As growing applications demand higher driving currents of oxide semiconductor thin-film transistors(TFTs),severe instabilities and even hard breakdown under high-current stress(HCS)become critical challenges.In this work,the triggering voltage of HCS-induced self-heating(SH)degradation is defined in the output characteristics of amorphous indium-galliumzinc oxide(a-IGZO)TFTs,and used to quantitatively evaluate the thermal generation process of channel donor defects.The fluorinated a-IGZO(a-IGZO:F)was adopted to effectively retard the triggering of the self-heating(SH)effect,and was supposed to originate from the less population of initial deep-state defects and a slower rate of thermal defect transition in a-IGZO:F.The proposed scheme noticeably enhances the high-current applications of oxide TFTs.
基金financially supported in part by Shenzhen Municipal Research Program(Grant NO.SGDX20211123145404006)in part by National Natural Science Foundation of China(Grant NO.62274111)+1 种基金in part by Guangdong Basic and Applied Basic Research Foundation(Grant NO.2021A1515011858)in part by Innovation and Technology Fund of Hong Kong(Grant NO.GHP/018/21SZ)。
文摘Indium-tin-zinc oxide(ITZO)thin-film transistor(TFT)technology holds promise for achieving high mobility and offers significant opportunities for commercialization.This paper provides a review of progress made in improving the mobility of ITZO TFTs.This paper begins by describing the development and current status of metal-oxide TFTs,and then goes on to explain the advantages of selecting ITZO as the TFT channel layer.The evaluation criteria for TFTs are subsequently introduced,and the reasons and significance of enhancing mobility are clarified.This paper then explores the development of high-mobility ITZO TFTs from five perspectives:active layer optimization,gate dielectric optimization,electrode optimization,interface optimization,and device structure optimization.Finally,a summary and outlook of the research field are presented.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 60676033 and 60276026)the Natural Science Foundation of Gansu Province,China (Grant No ZS031-A25-012-G)‘Qing Lan’ Talent Engineering Funds from Lanzhou Jiaotong University,China (Grant No QL-08-18A)
文摘Fabrication of ambipolar organic field-effect transistors (OFETs) is essential for the achievement of an organic complementary logic circuit. Ambipolar transports in OFETs with heterojunction structures are realized.We select pentacene as a P-type material and N,N'-bis(4-trifluoromethylben-zyl)perylene-3,4,9,10-tetracarboxylic diimide (PTCDI-TFB) as a n-type material in the active layer of the OFETs.The field-effect transistor shows highly air-stable ambipolar characteristics with a field-effect hole mobility of 0.18 cm^2/(V·s) and field-effect electron mobility of 0.031 cm^2/(V·s).Furthermore the mobility only slightly decreases after being exposed to air and remains stable even for exposure to air for more than 60 days.The high electron affinity of PTCDI-TFB and the octadecyltrichlorosilane (OTS) self-assembly monolayer between the SiO2 gate dielectric and the organic active layer result in the observed air-stable characteristics of OFETs with high mobility.The results demonstrate that using the OTS as a modified gate insulator layer and using high electron affinity semiconductor materials are two effective methods to fabricate OFETs with air-stable characteristics and high mobility.
基金supported by the National Basic Research Program of China(2013CB933500)National Natural Science Foundation of China(Grant Nos.61422403,51672180,51622306,21673151)+2 种基金Qing Lan ProjectCollaborative Innovation Center of Suzhou Nano Science and Technology(NANO-CIC)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Organic field-effect transistors(OFETs) based on organic micro-/nanocrystals have been widely reported with charge carrier mobility exceeding 1.0 cm^2V^(-1)s^(-1), demonstrating great potential for high-performance, low-cost organic electronic applications. However, fabrication of large-area organic micro-/nanocrystal arrays with consistent crystal growth direction has posed a significant technical challenge. Here, we describe a solution-processed dip-coating technique to grow large-area, aligned 9,10-bis(phenylethynyl) anthracene(BPEA) and 6,13-bis(triisopropylsilylethynyl) pentacene(TIPSPEN) single-crystalline nanoribbon arrays. The method is scalable to a 5 9 10 cm^2 wafer substrate, with around 60% of the wafer surface covered by aligned crystals. The quality of crystals can be easily controlled by tuning the dip-coating speed. Furthermore, OFETs based on well-aligned BPEA and TIPS-PEN single-crystalline nanoribbons were constructed.By optimizing channel lengths and using appropriate metallic electrodes, the BPEA and TIPS-PEN-based OFETs showed hole mobility exceeding 2.0 cm^2V^(-1)s^(-1)(average mobility 1.2 cm^2V^(-1)s^(-1)) and 3.0 cm^2V^(-1)s^(-1)(average mobility2.0 cm^2V^(-1)s^(-1)), respectively. They both have a high on/off ratio(I_(on)/I_(off))>10~9. The performance can well satisfy the requirements for light-emitting diodes driving.
基金Project supported by the National Natural Science Foundation of China(Grant No.61177032)the Foundation for Innovation Groups of the National Natural Science Foundation of China(Grant No.61021061)+1 种基金the Fundamental Research Funds for the Central Universities,China(Grant No.ZYGX2010Z004)the Scientific Research Staring Foundation for the Returned Overseas Chinese Scholars of the Education Ministry of China(Grant No.GGRYJJ08-05)
文摘Pentacene organic field-effect transistors (OFETs) based on single- or double-layer biocompatible dielectrics of poly(methyl methacrylate) (PMMA) and/or silk fibroin (SF) are fabricated. Compared with those devices based on sin- gle PMMA or SF dielectric or SF/PMMA bilayer dielectric, the OFETs with biocompatible PMMA/SF bilayer dielectric exhibit optimal performance with a high field-effect mobility of 0.21 cm2/Vs and a current on/off ratio of 1.5 × 104. By investigating the surface morphology of the pentacene active layer through atom force microscopy and analyzing the elec- trical properties, the performance enhancement is mainly attributed to the crystallization improvement of the pentacene and the smaller interface trap density at the dielectric/organic interface. Meanwhile, a low contact resistance also indicates that a good electrode/organic contact is formed, thereby assisting the performance improvement of the OFET.
基金supported by the National High Technology Research and Development Program of China (Grant No 2006AA03Z0412)the National Natural Science Foundation of China (Grant Nos 10774013 and 10804006)+4 种基金the Excellent Doctor’s Science and Technology Innovation Foundation of Beijing Jiaotong University (Grant No 48024)the Foundation of Beijing Jiaotong University (Grant No 2005SM057)the Research Fund for the Youth Scholars of the Doctoral Program of Higher Education (Grant No 20070004031)the Beijing NOVA program (Grant No 2007A024)Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘The properties of top-contact organic thin-film transistors (TC-OTFTs) using ultra-thin 2, 9-dimethyl-4, 7- diphenyl-1, 10-phenanthroline (BCP) as a hole-blocking interlayer have been improved significantly and a BCP interlayer was inserted into the middle of the pentacene active layer. This paper obtains a fire-new transport mode of an OTFT device with double-conductible channels. The accumulation and transfer of the hole carriers arc limited by the BCP interlayer in the vertical region of the channel. A huge amount of carriers is located not only at the interface between pentacene and the gate insulator, but also at the two interfaces of pentacene/BCP interlayer and pentacene/gate insulator, respectively. The results suggest that the BCP interlayer may be useful to adjust the hole accumulation and transfer, and can increase the hole mobility and output current of OTFTs. The TC-OTFTs with a BCP interlayer at VDS = --20 V showed excellent hole mobility μFE and threshold voltage VTH of 0.58 cm^2/(V-s) and -4.6 V, respectively.
基金Project supported by the National Grand Fundamental Research 973 Program of China (Grant No. 2010CB327704)the National Natural Science Foundation of China (Grant Nos. 10974013 and 60978060)+3 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20090009110027)the Natural Science Foundation of Beijing,China (Grant No. 1102028)the National Natural Science Foundation for Distinguished Young Scholars (Grant No. 60825407)Beijing Municipal Science and Technology Commission (Grant No. Z090803044009001)
文摘In this article, an organic thin-film field-effect transistor (OTFFET) with top-gate and bottom-contact geometry based on pentacene as the active layer is fabricated. The experimental data of the I-V are obtained from the OTFFET device. The alternating-current (AC) resistance value of the OTFFET device is calculated using the derivation method from the experimental data, and the AC resistance trend curves of the OTFFET device are obtained with the region fitting method. We analyse the characteristics of the OTFFET device with an AC resistance trend curve. To discover whether it has a high resistance, it is proposed to judge the region of the source/drain voltage (VDs) less than the transition voltage, thereby determining whether the contact between the metal electrode and the organic semiconductor layer of the OTFFET device is Ohmic or non-Ohmic. The theoretical analysis shows that the field-effect mobility and the AC resistance are in reverse proportion. Therefore, we point out that reducing AC resistance is necessary if field-effect mobility is to be improved.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10774013 and 10804006)the National High Technology Research and Development Program of China (Grant No. 2006AA03Z412)+3 种基金the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20070004024)the Research Fund for the Youth Scholars of the Doctoral Program of Higher Education, China (Grant No. 20070004031)the New Star Plan of Science and Technology of Beijing, China(Grant No. 2007A024)the research grants from the Academy of Sciences for the Developing World (Grant No. B08002)
文摘With the aim of understanding the relationships between organic small molecule field-effect transistors (FETs) and organic conjugated polymer FETs, we investigate the thickness dependence of surface morphology and charge carrier mobility in pentacene and regioregular poly (3-hexylthiophene) (RR-P3HT) field-effect transistors. On the basis of the results of surface morphologies and electrical properties, we presume that the charge carrier mobility is largely related to the morphology of the organic active layer. We observe that the change trends of the surface morphologies (average size and average roughness) of pentacene and RR-P3HT thin films are mutually opposite, as the thickness of the organic layer increases. Further, we demonstrate that the change trends of the field-effect mobilities of pentacene and RR-P3HT FETs are also opposite to each other, as the thickness of the organic layer increases within its limit.
基金Project(Z132012A001)supported by the Technical Basis Research Program in Science and Industry Bureau of ChinaProject(61201028,60876009)supported by the National Natural Science Foundation of China
文摘InGaAs high electron mobility transistors(HEMTs)on InP substrate with very good device performance have been grown by mental organic chemical vapor deposition(MOCVD).Room temperature Hall mobilities of the 2-DEG are measured to be over 8700cm2/V-s with sheet carrier densities larger than 4.6×10 12cm-2.Transistors with 1.0μm gate length exhibits transconductance up to 842mS/mm.Excellent depletion-mode operation,with a threshold voltage of-0.3V and IDSS of 673mA/mm,is realized.The non-alloyed ohmic contact special resistance is as low as 1.66×10-8Ω/cm2,which is so far the lowest ohmic contact special resistance.The unity current gain cut off frequency(fT)and the maximum oscillation frequency(fmax)are 42.7 and 61.3 GHz,respectively.These results are very encouraging toward manufacturing InP-based HEMT by MOCVD.
基金Project supported by the National Basic Research Program of China (Grant Nos. 2011CB808404 and 2009CB939703)the National Natural Science Foundation of China (Grant Nos. 10974074,90607022,60676001,60676008,and 60825403)
文摘This paper proposes an effective method of fabricating top contact organic field effect transistors by using a pho- tolithographic process. The semiconductor layer is protected by a passivation layer. Through photolithographic and etching processes, parts of the passivation layer are etched off to form source/drain electrode patterns. Combined with conventional evaporation and lift-off techniques, organic field effect transistors with a top contact are fabricated suc- cessfully, whose properties are comparable to those prepared with the shadow mask method and one order of magnitude higher than the bottom contact devices fabricated by using a photolithographic process.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10774013,10974013,60978060 and 10804006)the Research Fund for the Doctoral Program of Higher Education,China(Grant Nos.20090009110027,20070004024 and 20070004031)+1 种基金the Beijing Municipal Science and Technology Commission(Grant No.1102028)the National Basic Research Program of China(Grant No.2010CB327704)
文摘The contact effect on the performances of organic thin film transistors is studied here. A C60 ultrathin layer is inserted between Al source-drain electrode and pentacene to reduce the contact resistance. By a 3 nm C60 modification, the injection barrier is lowered and the contact resistance is reduced. Thus, the field-effect mobility increases from 0.12 to 0.52 cm2/(V.s). It means that inserting a C60 ultra thin layer is a good method to improve the organic thin film transistor (OTFT) performance. The output curve is simulated by using a charge drift model. Considering the contact effect, the field effect mobility is improved to 1.15 cm2/(V-s). It indicates that further reducing the contact resistance of OTFTs should be carried out.
基金supported by the National Key Technologies R&D Program,China(Grant No.2009ZX02302-002)the National Natural Science Foundation of China(Grant Nos.61376108,61076076,and 61076068)+2 种基金NSAF,China(Grant No.U1430106)the Science and Technology Commission of Shanghai Municipality,China(Grant No.13NM1400600)Zhuo Xue Plan in Fudan University,China
文摘Organic ferroelectric field-effect transistors (OFeFETs) are regarded as a promising technology for low-cost flexible memories. However, the electrical instability is still a critical obstacle, which limits the commercialization process. Based on already established models for polarization in ferroelectrics and charge transport in OFeFETs, simulation work is performed to determine the influence of polarization fatigue and ferroelectric switching transient on electrical characteristics in OFeFETs. The polarization fatigue results in the decrease of the on-state drain current and the memory window width and thus degrades the memory performance. The output measurements during the ferroelectric switching process show a hysteresis due to the instable polarization. In the on/off measurements, a large writing/erasing pulse frequency weakens the polarization modulation and thus results in a small separation between on- and off-state drain currents. According to the electrical properties of the ferroelectric layer, suggestions are given to obtain optimal electrical characterization for OFeFETs.