共查询到20条相似文献,搜索用时 15 毫秒
1.
P. Jha S.P. KoiryVibha Saxena P. VeerenderAbhay Gusain A.K. ChauhanA.K. Debnath D.K. AswalS.K. Gupta 《Organic Electronics》2013,14(10):2635-2644
We have fabricated flexible field-effect transistors (FETs) using poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)], PCDTBT, as an active channel, poly(methyl methacrylate) (PMMA) as gate dielectric and biaxially oriented polyethyleneterephthalate (BOPET) as supporting substrate. The output and transfer characteristics of the devices were measured as a function of channel length. It has been observed that various OFET parameters viz. on–off ratio (∼105), mobility (μ ∼ 10−4 cm2 V−1 s−1), threshold voltage (Vth ∼ −14 V), switch-on voltage (Vso ∼ −6 V), subthreshold slope (S ∼ 7 V/decade) and trap density (Nit ∼ 1014 cm−2 V−1) are almost independent of the channel length, which suggested a very high uniformity of the PCDTBT active layer. These devices were highly stable under atmospheric conditions (temperature: 20–35 °C and relative humidity: 70–85%), as no change in mobility was observed on a continuous exposure for 70 days. The studies on the effect of strain on mobility revealed that devices are stable up to a compressive or tensile strain of 1.2%. These results indicate that PCDTBT is a very promising active layer for the air stable and flexible FETs. 相似文献
2.
Nathan Cernetic Orb Acton Tobias Weidner Daniel O. Hutchins Joe E. Baio Hong Ma Alex K.-Y. Jen 《Organic Electronics》2012,13(12):3226-3233
Low-voltage, n-type organic field effect transistors (OFETs) with simultaneously modified bottom-contact (BC) electrodes and dielectric were compared to their top-contact (TC) counterparts. The devices modified with 6-phenoxyhexylphosphonic acid (Ph6PA) self-assembled monolayer (SAM) showed similar performance, morphology, and contact resistance. Electron mobility of C60 devices were 0.212 and 0.320 cm2 V−1 s−1 and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) devices were 0.04 and 0.06 cm2 V−1 s−1 for TC and BC devices, respectively. Low contact resistance between 11 and 45 kΩ cm was found regardless of device architecture or n-type semiconductor used. This work shows it is possible to fabricate solution processable low-voltage bottom-contact devices with performance that is similar or better than their top-contact counterparts without the addition of complex and time-consuming processing steps. 相似文献
3.
Xiaoyang Cheng Mario Caironi Yong-Young Noh Christopher NewmanJianpu Wang Mi Jung LeeKal Banger Riccardo Di PietroAntonio Facchetti Henning Sirringhaus 《Organic Electronics》2012,13(2):320-328
In this contribution we demonstrate for the first time a downscaled n-channel organic field-effect transistors based on N,N′-dialkylsubstituted-(1,7&1,6)-dicyanoperylene-3,4:9,10-bis(dicarboximide) with inkjet printed electrodes. First we demonstrate that the use of a high boiling point solvent is critical to achieve extended crystalline domains in spin-coated thin films and thus high electron mobility >0.1 cm2 V−1 s−1 in top-gate devices. Then inkjet-printing is employed to realize sub-micrometer scale channels by dewetting of silver nanoparticles off a first patterned gold contact. By employing a 50 nm crosslinked fluoropolymer gate dielectric, ∼200 nm long channel transistors can achieve good current saturation when operated <5 V with good bias stress stability. 相似文献
4.
N-octylphosphonic acid (C8PA) monolayer was self-assembled on aluminum oxide (AlOx) from vapor in vacuum, while the substrate temperature was varied between 25 and 150 °C. The capacitance, water contact angle measurement, Fourier transform infrared (FTIR) spectroscopy, and atomic force microscopy (AFM) confirmed the presence of C8PA on AlOx for all growth temperatures. However, the structural and electrical properties of such monolayers depend on their growth temperature. The minimum surface roughness of 0.36 nm, the maximum water contact angle of 113.5° ± 1.4°, the lowest leakage current density of ∼10−7 A/cm2 at 3 V, and the capacitance of 0.43 μF/cm2 were obtained for AlOx/C8PA bi-layers with C8PA deposited at 25 °C. The elevated temperature led to increased surface roughness, decreased water contact angle, increased leakage current, inferior molecular ordering, and lower molecular coverage; while the effect on the chemisorption of the phosphonate was minimal. Methyl and methylene FTIR vibrations associated with C8PA aliphatic tails exhibited similar centre-peak wavenumbers to those observed for C8PA monolayers assembled from solutions, presenting a viable ‘dry’ alternative to the existing solution process. 相似文献
5.
Andreas Petritz Archim Wolfberger Alexander Fian Joachim R. Krenn Thomas Griesser Barbara Stadlober 《Organic Electronics》2013,14(11):3070-3082
A high-performing bottom-gate top-contact pentacene-based oTFT technology with an ultrathin (25–48 nm) and electrically dense photopatternable polymeric gate dielectric layer is reported. The photosensitive polymer poly((±)endo,exo-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid, diphenylester) (PNDPE) is patterned directly by UV-exposure (λ = 254 nm) at a dose typical for conventionally used negative photoresists without the need for any additional photoinitiator. The polymer itself undergoes a photo-Fries rearrangement reaction under UV illumination, which is accompanied by a selective cross-linking of the macromolecules, leading to a change in solubility in organic solvents. This crosslinking reaction and the negative photoresist behavior are investigated by means of sol–gel analysis. The resulting transistors show a field-effect mobility up to 0.8 cm2 V−1 s−1 at an operation voltage as low as −4.5 V. The ultra-low subthreshold swing in the order of 0.1 V dec−1 as well as the completely hysteresis-free transistor characteristics are indicating a very low interface trap density. It can be shown that the device performance is completely stable upon UV-irradiation and development according to a very robust chemical rearrangement. The excellent interface properties, the high stability and the small thickness make the PNDPE gate dielectric a promising candidate for fast organic electronic circuits. 相似文献
6.
Chunyu Zhang He Wang Zuosen Shi Zhanchen Cui Donghang Yan 《Organic Electronics》2012,13(12):3302-3309
A research on the design, synthesis, and characterization of novel cross-linked polymer organic–inorganic hybrid materials as gate insulators for organic thin-film transistors (OTFTs) with vanadyl-phthalocyanine as the organic semiconductor is presented. The hybrid films (0.5–1.2 μm thick) can be easily prepared by sol–gel technology and fabricated by spin-coating a mixture of zirconium n-butoxide sol with a side-chain triethoxysilane-capped polyurethane solution in ambient conditions, followed by curing at low temperatures (∼120 °C) and cross-linking under UV light. OTFTs with this film as gate insulator were achieved with good processability, high charge-carrier mobility of 0.56 cm2/Vs, surface roughness of around 0.49–0.59 nm, ultralow threshold of −6 V, and ultralow leakage of 0.24 mA. Hybrid films with various compositions were investigated, and the results showed that the field-effect mobility of the OTFTs was dominated by the high dielectric constant component ZrO2. The result indicated that these hybrid materials are promising candidates for the exploration of devices using OTFTs. 相似文献
7.
Hanah Na Hyejin Cho Kyoseung Sim Hyunseok Shim Sung-Jin Kim Seungmoon Pyo 《Organic Electronics》2014,15(11):2728-2733
We report a formation of a solution-grown single crystal wire mask for the fabrication of short-channel organic field-effect transistor with enhanced dynamic response time. The various channel length, ranging from submicrometer to a few micrometers, were obtained by controlling the concentration of solution and processing conditions. We fabricated p- and n-channel bottom-contact organic field-effect transistors using pentacene and PTCDI-C13, respectively, and static and dynamic electrical characteristics of the devices were investigated. The highest and average field-effect hole mobility values were found to be 0.892 cm2/V s and 0.192 cm2/V s, respectively. The load type inverter based on the short-channel transistor connected with a 2 MΩ resistor showed a clear switching response when square wave input signals up to 1 kHz were applied at VDD = −60 V. 相似文献
8.
We have developed a practical printing technology for the gate electrode of organic thin film transistors (OTFTs) by combining screen-printing with a wet-etching process using nano-silver (Ag) ink as a conducting material. An Ag film was deposited onto a PVP (polyvinylphenol)-coated PC (polycarbonate) plastic substrate by screen-printing with nano-Ag ink, where Ag content of 20 wt.% was mixed using a terpineol solvent. Subsequently, the film was cured at 200 °C for 60 min, and then finally wet-etched through patterned positive photo-resist masks. The screen-printed Ag electrode exhibited a minimum line width of ∼5 μm, a thickness of ∼65 nm, and a resistivity of ∼10−6 Ω cm, producing good geometrical and electrical characteristics for a gate electrode. Additionally, it also provided good step coverage with the PVP dielectric layer, and consequently leakage current between the gate and source/drain electrodes was eliminated. Moreover, the electrical characteristic of the screen-printed Ag electrode was not significantly changed even after a bending test in which the Ag electrodes were bent with a bending radius of 6 mm and 2500 iterations of cyclic bending. OTFTs with the screen-printed Ag electrode produced a saturation mobility of 0.13 cm2/Vs and a current on/off ratio of 1.79 × 106, being comparable to those of an OTFT with a thermally evaporated Al gate electrode. 相似文献
9.
Roberto Centore Laura Ricciotti Antonio Carella Antonio Roviello Mauro Causà Mario Barra Francesca Ciccullo Antonio Cassinese 《Organic Electronics》2012,13(10):2083-2093
Two new perylene diimide derivatives N,N′-bis(5-tridecyl-1,3,4-thiadiazol-2-yl)perylene-3,4,9,10-tetracarboxylic 3,4:9,10-diimide (PDI-T1) and N,N′-bis[5-(1-hexyl)nonyl-1,3,4-thiadiazol-2-yl]perylene-3,4,9,10-tetracarboxylic 3,4:9,10-diimide (PDI-T2), achieved by functionalizing the basic perylene molecular core at imide nitrogen with 1,3,4-thiadiazole rings, have been synthesized. Both these compounds make possible the fabrication of n-type organic thin-film transistors able to work in air, even when bare SiO2 surfaces are utilized as gate dielectric. As active channels of transistors in the bottom-contact bottom-gate configuration, PDI-T1 evaporated films exhibited a maximum mobility of 0.016 cm2/V s in vacuum. For evaporated PDI-T2 films, instead, mobility values were found to be more than one order of magnitude lower, because of their reduced degree of crystalline order. However, PDI-T2 films can be also deposited by solution techniques and field-effect transistors were fabricated by spin-coating, displaying mobility values ranging between 10−6 and 10−5 cm2/V s. Similar to what previously found for other perylene diimide derivatives, our experimental work also demonstrates that the electrical response of both PDI-T1 and PDI-T2 transistors under ambient conditions can be improved by increasing the level of hydrophobicity of the dielectric surface. 相似文献
10.
A double gate normally-off silicon carbide (SiC) trench junction field effect transistors (JFET) design is considered. Innovative migration enhanced embedded epitaxial (ME3) growth process was developed to replace the implantation process and realize high device performance. Strong anisotropic behavior in electrical characteristics of the pn junction fabricated on (1 1 −2 0) and (1 −1 0 0) trench a-planes was observed, although quality of the pn diodes was found to be independent of trench plane orientations. Fabricated normally-off trench 4H-SiC JFET demonstrates the potential for lower specific on-resistance (RonS) in the range of 5-10 mΩ cm2 (1200 V class). A relative high T−2.6 dependence of RonS is observed. A breakdown voltage of 400 V in the avalanche mode was confirmed at zero gate bias conditions for cell design without edge termination. It was demonstrated that the normally-off JFETs are suitable for high temperature applications. Average temperature coefficient of threshold voltage (Vth) was calculated as −1.8 mV/°C, which is close to the MOS based Si power devices. 相似文献
11.
Kalpana Besar Shyuan Yang Xin Guo Weiguo Huang Ana M. Rule Patrick N. Breysse Ioannis J. Kymissis Howard E. Katz 《Organic Electronics》2014,15(11):3221-3230
We report an organic field-effect transistor (OFET)-based sensor made from printable materials with an unusually high sensitivity of 0.5 ppm v/v for ammonia and with limit of detection on the order of 0.1 ppm v/v. The device developed has a polyethylene terephthalate (PET) substrate, bottom contacts, and poly (3,3?-didodecylquaterthiophene) (PQT-12) cast from 4 mg/mL cholorobenzene solution as active semiconductor. The fabrication process is simplified by replacing the gate electrode and dielectric deposition steps with the introduction of static charges on the back surface of the PET substrate by corona charging, a procedure that is adaptable to roll-to-roll processing. Hydrophobic polymers applied to the back surface stabilize this charge, providing evidence for their activity at that location. In the proposed sensor, these static charges are used as a static gate, reducing the OFET architecture to a chemiresistor. The sensor is selective for ammonia over common organic solvent vapors, and the response is generally reversible. The device also demonstrates memory behavior required for dosimetric sensors when kept at low temperature (4 °C to −30 °C). A converse response from an n-channel semiconductor is also reported. 相似文献
12.
In this paper we describe a method to form NiSi contacts using electroless plating of Nickel or Ni alloy on Pd activated self-assembled monolayer (SAM) on p-type Si(1 0 0). Such method allows uniform deposition of very thin, <30 nm, Ni or Ni alloy films. Clean, oxide free, Si substrate was covered with aminopropyltriethoxysilane (APTES) self-assembled monolayer. The surface was activated with Pd-citrate solution followed by electroless plating. The samples were annealed for 1 h in vacuum (∼10−6 Torr) forming the silicide layer. The annealing temperatures were 400 °C for NiP alloy and 500 °C for NiPW alloy. X-ray diffraction (XRD) measurement confirmed the presence of NiSi phase after annealing. The silicides material properties were characterized using secondary electron microscopy (SEM) analysis, X-ray diffraction (XRD) and X-ray photon spectroscopy (XPS) profiling. The results are reported and summarized. 相似文献
13.
Andreas Ringk Xiaoran Li Fatemeh Gholamrezaie Edsger C. P. Smits Alfred Neuhold Armin Moser Cees Van der Marel Gerwin H. Gelinck Roland Resel Dago M. de Leeuw Peter Strohriegl 《Advanced functional materials》2013,23(16):2016-2023
This work describes n‐type self‐assembled monolayer field‐effect transistors (SAMFETs) based on a perylene derivative which is covalently fixed to an aluminum oxide dielectric via a phosphonic acid linker. N‐type SAMFETs spontaneously formed by a single layer of active molecules are demonstrated for transistor channel length up to 100 μm. Highly reproducible transistors with electron mobilities of 1.5 × 10?3 cm2 V?1 s?1 and on/off current ratios up to 105 are obtained. By implementing n‐type and p‐type transistors in one device, a complimentary inverter based solely on SAMFETs is demonstrated for the first time. 相似文献
14.
Xiaolan Qiao Lizhen Huang Weichao Chen Hao Chang Jidong Zhang Donghang Yan 《Organic Electronics》2012,13(11):2406-2411
The film morphology, structure, and electrical properties of lead phthalocyanine (PbPc) epitaxially grown on 5,5″-bis(3′-fluoro-biphenyl-4-yl)-2,2′:5′,2″-terthiophene (m-F2BP3T) inducing layer substrates were systematic investigated. The morphologies of PbPc films sensitively depend on the thickness of the inducing layer and substrate temperature. All the epitaxial PbPc films with high quality presented the triclinic form with a variation of the out-of-plane orientation. The field-effect mobility of the epitaxial PbPc films was 0.05–0.31 cm2/V s, which was significantly improved by 1–2 orders of magnitude compared to the traditional films. The evolution of the device performance is the synergistic effect of the morphology and out-of-plane orientation of the triclinic form of PbPc. The higher quality of the films and the smaller ratio of (1 0 0)/(0 0 1), the higher device performance is. A clear relationship between the morphology, structure, and the performance of epitaxial PbPc-based organic field-effect transistors was reported. 相似文献
15.
Serafina CotroneMarianna Ambrico Henrik TossM. Daniela Angione Maria MagliuloAntonia Mallardi Magnus BerggrenGerardo Palazzo Gilles HorowitzTeresa Ligonzo Luisa Torsi 《Organic Electronics》2012,13(4):638-644
A totally innovative electrolyte-gated field effect transistor, embedding a phospholipid film at the interface between the organic semiconductor and the gating solution, is described. The electronic properties of OFETs including a phospholipid film are studied in both pure water and in an electrolyte solution and compared to those of an OFET with the organic semiconductor directly in contact with the gating solution. In addition, to investigate the role of the lipid layers in the charge polarization process and quantify the field-effect mobility, impedance spectroscopy was employed. The results indicate that the integration of the biological film minimizes the penetration of ions into the organic semiconductor thus leading to a capacitive operational mode as opposed to an electrochemical one. The OFETs operate at low voltages with a field-effect mobility in the 10−3 cm2 V−1 s−1 range and an on/off current ratio of 103. This achievement opens perspectives to the development of FET biosensors potentially capable to operate in direct contact with physiological fluids. 相似文献
16.
Yuze Lin Pei Cheng Yao Liu Qinqin ShiWenping Hu Yongfang LiXiaowei Zhan 《Organic Electronics》2012,13(4):673-680
A series of donor-acceptor-donor small molecules (1-3) with bithiazole as acceptor unit, triphenylamine as donor unit and thiophene with different number (0, 1, 2) as bridge were synthesized by palladium(0)-catalyzed Suzuki or Stille coupling reactions. The thermal, optical, electrochemical, charge transport, and photovoltaic properties of these small molecules were examined. All compounds exhibit excellent thermal stability with decomposition temperatures (5% weight loss) over 390 °C in nitrogen atmosphere. As increasing the number of thiophene and π-conjugation length of molecule, the absorption maximum in film red shifts from 406 to 498 nm, the extinction coefficient increases from 1.35 × 104 to 7.66 × 104 M−1 cm−1, and the optical band gap decreases from 2.6 to 2.0 eV. The electron-donating thiophene and bithiophene in compounds 2 and 3 up-shift HOMO energy level from −5.42 (1) to −5.24 eV (2) or −5.22 eV (3), and down-shift LUMO energy level from −2.48 (1) to −2.84 eV (2) or −2.81 eV (3). The hole mobility of compound 3 is up to 3.6 × 10−4 cm2 V−1 s−1, which is one order of magnitude higher than that of compound 2, but compound 1 shows no field-effect transistor performance. Solution-processed bulk heterojunction organic solar cells based on 1-3:PC71BM (1:4, w/w) blend films exhibit increasing power conversion efficiency (up to 2.61%) as increasing thiophene unit number. 相似文献
17.
Yagang Chen Hao Chang Hongkun Tian Cheng Bao Weili Li Donghang Yan Yanhou Geng Fosong Wang 《Organic Electronics》2012,13(12):3268-3275
A novel easily made thienoacene-based organic semiconductor, i.e., dinaphtho[3,4-d:3′,4′-d′]benzo[1,2-b:4,5-b′]dithiophene (Ph5T2), was synthesized in high yield, and its thermal stability, electrochemical properties, thin-film morphology and field-effect mobility were investigated. Ph5T2 exhibit excellent thermal stability with a decomposition temperature (Td) of 427 °C. Thin-film X-ray diffraction (XRD) and atomic force microscopy (AFM) characterizations indicate that Ph5T2 can form highly ordered films with large domain size on the para-sexiphenyl (6P)-modified substrates. Organic thin-film transistors (OTFTs) with top-contact geometry based on Ph5T2 exhibit mobilities up to 1.2 cm2 V−1 s−1 in ambient. The devices are highly stable and exhibit almost no performance degradation during 3 months storage under ambient conditions with relative humidity up to 80%. 相似文献
18.
Shun-Wei Liu Wei-Cheng Su Chih-Chien Lee Chi-Feng Lin Shih-Chieh Yeh Chin-Ti Chen Jiun-Haw Lee 《Organic Electronics》2012,13(10):2118-2129
Buckminsterfullerene, C60-based planar heterojunction (PHJ) organic photovoltaics (OPVs) have been created using a short wavelength absorption (λmax = 490 nm) electron-donating bis(naphthylphenylaminophenyl)fumaronitrile (NPAFN). NPAFN exhibits a hole mobility greater than 0.07 cm2 V−1 s−1 as determined by its field-effect transistor. It can be attributed to such hole mobility that enables a thin layer (<10 nm) NPAFN in PHJ OPV, ITO/NPAFN/C60/bathocuproine/Al. Because of the low lying HOMO energy level (5.75 eV) of NPAFN and relatively high ionization potential ITO (∼5.58 eV), such OPVs exhibit a very high open circuit voltage of ∼1.0 V, relatively high fill factor of 0.60, and a relatively high shunt resistance of 1100 Ω cm−2, which all compensate for a relatively low short circuit current of 3.15 mA cm−2 due to the short absorption wavelength and inferred short exciton diffusion length of NPAFN. Altogether, NPAFN OPVs display a power conversion efficiency (ηPC) of 2.22%, which is better than other long wavelength absorption materials in similar PHJ OPVs, such as pentacene (λmax 670 nm, HOMO 5.12 eV, ηPC 1.50%) and copper phthalocyanine (λmax 624, 695 nm, HOMO 5.17 eV, ηPC 1.43%). 相似文献
19.
E.M. Lopes R.S. Ywata N. Alves F.M. Shimizu D.M. Taylor C.P. Watson A.J.F. Carvalho J.A. Giacometti 《Organic Electronics》2012,13(10):2109-2117
The admittance spectra and current–voltage (I–V) characteristics are reported of metal–insulator–metal (MIM) and metal–insulator–semiconductor (MIS) capacitors employing cross-linked poly(amide–imide) (c-PAI) as the insulator and poly(3-hexylthiophene) (P3HT) as the active semiconductor. The capacitance of the MIM devices are constant in the frequency range from 10 Hz to 100 kHz, with tan δ values as low as 7 × 10−3 over most of the range. Except at the lowest voltages, the I–V characteristics are well-described by the Schottky equation for thermal emission of electrons from the electrodes into the insulator. The admittance spectra of the MIS devices displayed a classic Maxwell–Wagner frequency response from which the transverse bulk hole mobility was estimated to be ∼2 × 10−5 cm2 V−1s−1 or ∼5 × 10−8 cm2 V−1s−1 depending on whether or not the surface of the insulator had been treated with hexamethyldisilazane (HMDS) prior to deposition of the P3HT. From the maximum loss observed in admittance-voltage plots, the interface trap density was estimated to be ∼5 × 1010 cm−2 eV−1 or ∼9 × 1010 cm−2 eV−1 again depending whether or not the insulator was treated with HMDS. We conclude, therefore, that HMDS plays a useful role in promoting order in the P3HT film as well as reducing the density of interface trap states. Although interposing the P3HT layer between the insulator and the gold electrode degrades the insulating properties of the c-PAI, nevertheless, they remain sufficiently good for use in organic electronic devices. 相似文献
20.
Jagan Singh Meena 《Microelectronics Reliability》2010,50(5):652-656
We have used a sol-gel spin-coating process to fabricate a new metal-insulator-metal capacitor comprising 10-nm thick binary hafnium-zirconium-oxide (HfxZr1−xO2) film on a flexible polyimide (PI) substrate. The surface morphology of this HfxZr1−xO2 film was investigated using atomic force microscopy and scanning electron microscopy, which confirmed that continuous and crack-free film growth had occurred on the PI. After oxygen plasma pre-treatment and subsequent annealing at 250 °C, the film on the PI substrate exhibited a low leakage current density of 3.22 × 10−8 A/cm2 at −10 V and maximum capacitance densities of 10.36 fF/μm2 at 10 kHz and 9.42 fF/μm2 at 1 MHz. The as-deposited sol-gel film was oxidized when employing oxygen plasma at a relatively low temperature (∼250 °C), thereby enhancing the electrical performance. 相似文献