Using two layers of pentacene deposited at different substrate temperatures as the active material, we have fabricated photolithographically defined organic thin-film transistors (OTFTs) with improved field-effect mobility and subthreshold slope. These devices use gold source drain electrodes octadecyltrichlorosilane-treated silicon dioxide gate dielectric. The large 1.5 cm/sup 2//V-s, on/off current ratio larger than 10/sup 8/, near zero threshold voltage, slope less 1.6 V per decade. To...

This letter describes an electric-field assisted assembly technique used to position individual nanowires suspended in a dielectric medium between two electrodes defined lithographically on SiO2 substrate. During the process, forces that induce alignment are result of nanowire polarization applied alternating electric field. approach has facilitated rapid electrical characterization 350- and 70-nm-diameter Au nanowires, which had room-temperature resistivities approximately 2.9 4.5×10−6 Ω cm.

The charge-carrier transport mechanism in the organic semiconductor pentacene is explored using thin-film transistor structures. variation of field-effect mobility with temperature differs from sample to sample, ranging thermally activated temperature-independent behavior. This result excludes hopping as fundamental thin films, and suggests that traps and/or contact effects may strongly influence observed characteristics. These results also indicate transistors not be appropriate vehicles...

Pentacene-based organic thin-film transistors (TFT's) with field-effect mobility as large 0.7 cm/sup 2//V/spl middot/s and on/off current ratio larger than 10/sup 8/ have been fabricated. Pentacene films deposited by evaporation at elevated temperature low-to-moderate deposition rates a high degree of molecular ordering micrometer-sized dendritic grains. Such yield TFT's mobility. Films low or flash small grains poor

We have fabricated organic thin-film transistor (OTFT)-driven active matrix liquid crystal displays on flexible polymeric substrates. These small 16×16 pixel polymer-dispersed arrays addressed by pentacene layer OTFTs. The were using a low-temperature process (<110 °C) polyethylene naphthalate film and are operated as reflective displays.

We present the device parameters for organic field-effect transistors fabricated from solution-deposited films of functionalized pentacene and anthradithiophenes. These materials are easily prepared in one or two steps commercially available starting purified by simple recrystallization. For a film pentacene, hole mobility 0.17 cm2/V·s was measured. The anthradithiophenes showed behavior strongly dependent on substituents, with mobilities as high 1.0 cm2/V·s.

Using the small molecule organic semiconductor 6,13-bis(triisopropyl-silylethynyl) pentacene (TIPS-pentacene), authors have fabricated solution-processed thin film transistors (OTFTs) with carrier mobility >1cm2∕Vs, current on/off ratio greater than 107, and subthreshold slope <0.3V/decade. The high TIPS-pentacene films are deposited from boiling point solvents show strong molecular ordering including terracing. Film varies substantially for different deposition techniques OTFT...

We have fabricated pentacene organic thin-film transistor (OTFT) driven active matrix light-emitting diode (OLED) displays on flexible polyethylene terephthalete substrates. These 48×48 bottom-emission OLED pixels with two OTFTs used per pixel. Parylene is to isolate the and OLEDs good OTFT yield uniformity.

Organic thin-film transistors using the fused-ring polycyclic aromatic hydrocarbon pentacene as active electronic material have shown mobility large 0.7 cm/sup 2//V-s and on/off current ratio larger than 10/sup 8/; both values are comparable to hydrogenated amorphous silicon devices. On other hand, these most organic TFT's an undesirably subthreshold slope. We show here that slope typically observed is not intrinsic property of semiconducting devices with similar possible.

Parameters used to describe the electrical properties of organic field-effect transistors, such as mobility and threshold voltage, are commonly extracted from measured current-voltage characteristics interpreted by using classical metal oxide-semiconductor transistor model. However, in recent reports devices with ultra-high (>40 cm(2) V(-1) s(-1)), device deviate this idealized model show an abrupt turn-on drain current when a function gate voltage. In order investigate phenomenon, here we...

We report on parasitic contact effects in organic thin film transistors (OTFTs) fabricated with pentacene films. The influence the OTFT performance of source and drain metal device design was investigated. Top (TC) bottom (BC) gated transmission line model (gated-TLM) test structures were used to extract combined resistance as a function gate voltage swing drain-source for OTFTs gold contacts. For comparison BC palladium contacts studied. Differences bias dependence TC indicate that charge...

Organic thin‐film transistors with active layers of five different functionalized pentacene derivatives (see Figure) have been fabricated. The molecules are to encourage face‐to‐face molecular interactions and thus increase π‐orbital overlap carrier field‐effect mobility. Devices fabricated using triisopropylsilyl the highest mobility (0.4 cm 2 V –1 s ) on/off current ratio (10 6 ).

We report dramatic improvements in the stability and crystallinity arising from partial fluorination of soluble anthradithiophene derivatives. These fluorinated materials still behave as p-type semiconductors but with increases thermal photostability compared to non-fluorinated The triethylsilyl-substituted material forms highly crystalline films even spin-cast solutions, leading devices maximum hole mobility greater than 1.0 cm2/V s. In contrast, triisopropylsilyl derivative large,...

This article provides the latest advances from NSF Advanced Self-powered Systems of Integrated sensors and Technologies (ASSIST) center. The work in center addresses key challenges wearable health environmental systems by exploring technologies that enable ultra-long battery lifetime, user comfort wearability, robust medically validated sensor data with value added multimodal sensing, access to open architecture streams. vison ASSIST is use nanotechnology build miniature, self-powered,...

A far ultraviolet (UV) spectroscopic ellipsometer system working up to 9 eV has been developed, and applied characterize high-K-dielectric materials. These materials have gaining greater attention as possible substitutes for SiO2 gate dielectrics in aggressively scaled silicon devices. The optical properties of four representative high-K bulk crystalline dielectrics, LaAlO3, Y2O3-stabilized HfO2 (Y2O3)0.15–(HfO2)0.85, GdScO3, SmScO3, were investigated with UV ellipsometry visible-near...

We report on modeling of direct current (DC) characteristics organic pentacene thin film transistors different designs. Our model incorporates a gate-voltage dependent mobility and highly nonlinear drain source contact series resistances. The nonlinearities are especially pronounced in bottom transistors. successfully reproduced both below- above-threshold top

We have fabricated organic thin-film transistors (TFT's) using the small-molecule polycyclic aromatic hydrocarbon pentacene as active material. Devices were on glass substrates low-temperature ion-beam deposited silicon dioxide gate dielectric, palladium for source and drain contacts, vacuum-evaporated to form layer. Excellent electrical characteristics obtained, including carrier mobility large 0.6 cm/sup 2//V-s, on/off current ratio 10/sup 8/, subthreshold slope low 0.7 V/dec, all record...

We report a solvent-induced phase transition in pentacene thin films, from “thin film” to bulk-like phase. X-ray diffraction indicates that as-deposited thermally evaporated films consist mainly of (001)-oriented with an elongated (001) plane spacing 15.5±0.1 Å, and minor amount 14.5±0.1 Å. When such are exposed solvents as acetone, isopropanol, or ethanol, the entire layer shifts abruptly bulk value this shift is accompanied by macroscopic change film morphology. While molecular ordering...

We report on a study of Al and Ti/Al contacts to n-type GaN. n-GaN (7×1017 cm−3) annealed in forming gas at 600 °C reached minimum contact resistivity 8×10−6 Ω cm2 had much better thermal stability than reported by previous researchers. (35/115 nm) (5×1017 resistivities 7×10−6 5×10−6 after annealing Ar 400 for 5 min 15 s, respectively. Depth profiles showed that low resistance was only achieved diffused the GaN interface. propose mechanism Ohmic formation 400–600 range includes Ti reducing...

The interface structures resulting from the alloying reactions between a Au/Ni/Au-Ge composite film and (100) GaAs substrate were studied by transmission electron microscopy scanning microscopy. Electron microscope examinations of cross-sectional samples prepared in this study offered excellent lateral depth resolution local which are not available other analytical techniques used previously similar studies. distributions chemical compositions various phases formed, morphologies interfaces...

We report on organic thin-film transistors fabricated using the small-molecule semiconductor naphthacene as active layer material with device performance suitable for several large-area or low-cost electronics applications. investigated thin films deposited by thermal evaporation onto amorphous substrates held near room temperature. Using atomic-force microscopy and x-ray diffraction we find consist of a high density submicron-sized grains surprisingly degree molecular order. Thin-film...