Mixed alkyl/fluoroalkyl phosphonic acid self‐assembled monolayers have been prepared as ultra‐thin dielectrics in low‐voltage organic thin‐film transistors and complementary circuits. Mixed ...monolayers enable continuous threshold‐voltage tuning simply by adjusting the molecular mixing ratio Continuous threshold‐voltage control makes it possible to place the switching voltage of the circuits at precisely half the supply voltage, producing the maximum noise margin.
Bottom‐gate, top‐contact organic thin‐film transistors (TFTs) with excellent static characteristics (on/off ratio: 107; intrinsic mobility: 3 cm2 (V s)−1) and fast unipolar ring oscillators (signal ...delay as short as 230 ns per stage) are fabricated. The significant contribution of the transfer length to the relation between channel length, contact length, contact resistance, effective mobility, and cutoff frequency of the TFTs is theoretically and experimentally analyzed.
To suppress undesirable short‐channel effects in organic transistors with nanoscale lateral dimensions, aggressive gate‐dielectric scaling (using an ultra‐thin monolayer‐based gate dielectric) and ...area‐selective contact doping (using a strong organic dopant) are introduced into organic transistors with channel lengths and gate‐to‐contact overlaps of about 100 nm. These nanoscale organic transistors have off‐state drain currents below 1 pA, on/off current ratios near 107, and clean linear and saturation characteristics.
Flexible transistors and circuits based on dinaphtho‐2,3‐b:2′,3′‐fthieno3,2‐bthiophene (DNTT), a conjugated semiconductor with a large ionization potential (5.4 eV), are reported. The transistors ...have a mobility of 0.6 cm2 V−1 s−1 and the ring oscillators have a stage delay of 18 µs. Due to the excellent stability of the semiconductor, the devices and circuits maintain 50% of their initial performance for a period of 8 months in ambient air.
An important prerequisite for the design of digital integrated circuits is the ability to control the threshold voltage of the individual transistors during manufacturing. To address the problem of ...controlling the threshold voltage of low-voltage organic transistors we have synthesized a fluoroalkylphosphonic acid that forms selfassembled monolayers on patterned, plasma-oxidized aluminum gate electrodes for use as high-capacitance, low-temperature gate dielectrics in p-channel and n-channel organic transistors. Compared with alkyl phosphoric acid-based monolayers, the strong electron-withdrawing character of the fluoroalkyl monolayers causes a change in the threshold voltage of the transistors by about 1 V, i.e. almost half of the supply voltage.
Display omitted
► DNTT thin-film transistors have mobilities up to 2
cm
2/V
s and on/off ratio of 10
8. ► DNTT thin-film transistors have better air stability than pentacene transistors. ► Unipolar ...ring oscillators oscillate with a signal delay of 7
μ
sec at 5
V.
Organic thin-film transistors based on the vacuum-deposited small-molecule conjugated semiconductor dinaphtho2,3-b:2′,3′-fthieno3,2-bthiophene (DNTT) have been fabricated and characterized. The transistors have field-effect mobilities as large as 2
cm
2/V
s and an on/off ratio of 10
8. Owing to the large ionization potential of DNTT, the TFTs show excellent stability for periods of several months of storage in ambient air. Unipolar ring oscillators based on DNTT TFTs with a channel length of 10
μm oscillate with a signal propagation delay as short as 7
μsec per stage at a supply voltage of 5
V. We also show that DNTT TFTs with usefully small channel width/length ratio are able to drive blue organic LEDs to a brightness well above that required for active-matrix displays.
A 3.3 V 6-bit binary-weighted current-steering digital-to-converter converter (DAC) using low-voltage organic p-type thin-film transistors (OTFTs) is presented. The converter marks records in speed ...and compactness owing to an OTFT fabrication process that is based on high-resolution silicon stencil masks. The chip has been fabricated on a glass substrate and consumes an area of 2.6× 4.6 mm 2 . The converter has a maximum update rate of 100 kS/s and a maximum output voltage swing of 2 V. The measured DNL and INL at an update rate of 1 kS/s are - 0.69 and 1.16 LSB, respectively. A spurious-free dynamic range (SFDR) of 32 dB has been measured for output sinusoids at 31 Hz (update rate of 1 kS/s) and 3.1 kHz (update rate of 100 kS/s).
Low-voltage-driven organic thin-film transistors (organic TFTs) with spatially controlled threshold voltages (-1.2 and -0.36 V) were fabricated for the first time. Using the microcontact printing ...method, tetradecylphosphonic acid (HC14-PA)and pentadecylfluoro-octadecylpho-sphonic acid (FC18-PA) were transferred to form ultrathin layers in different regions on a substrate. Together with plasma-grown aluminum oxide (AIO
x
) layer, the stamped layers were shown to have equal insulating ability as the dipped method monolayer. The feasibility of the area-selective stamping method was displayed using locally controlled inverter circuits. The shift of turn-on voltage for those transistors was consistent with the threshold voltage shift of the transistors.
A novel approach for the fabrication of transistors and circuits based on individual single-crystalline ZnO nanowires synthesized by a low-temperature hydrothermal method is reported. The gate ...dielectric of these transistors is a self-assembled monolayer that has a thickness of 2 nm and efficiently isolates the ZnO nanowire from the top-gate electrodes. Inverters fabricated on a single ZnO nanowire operate with frequencies up to 1 MHz. Compared with metal–semiconductor field-effect transistors, in which the isolation of the gate electrode from the carrier channel relies solely on the depletion layer in the semiconductor, the self-assembled monolayer dielectric leads to a reduction of the gate current by more than 3 orders of magnitude.
![Dinaphtho[2,3-b:2′,3′-f]thi...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/1566-1199/small "Dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) thin-film transistors with improved performance and stability")
PDF