Bottom-gate, top-contact organic thin-film transistors (TFTs) with excellent static characteristics (on/off ratio: 10(7) ; intrinsic mobility: 3 cm(2) (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.

Physical properties of active materials built up from small molecules are dictated by their molecular packing in the solid state. Here we demonstrate for the first time the growth of n-channel single-crystal field-effect transistors and organic thin-film transistors by sublimation of 2,6-dichloro-naphthalene diimide in air. Under these conditions, a new polymorph with two-dimensional brick-wall packing mode (b-phase) is obtained that is distinguished from the previously reported herringbone packing motif obtained from solution (a-phase). We are able to fabricate single-crystal field-effect transistors with electron mobilities in air of up to 8.6 cm 2 V À 1 s À 1 (a-phase) and up to 3.5 cm 2 V À 1 s À 1 (b-phase) on n-octadecyltriethoxysilane-modified substrates. On silicon dioxide, thin-film devices based on b-phase can be manufactured in air giving rise to electron mobilities of 0.37 cm 2 V À 1 s À 1 . The simple crystal and thin-film growth procedures by sublimation under ambient conditions avoid elaborate substrate modifications and costly vacuum equipment-based fabrication steps.

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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.

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.