Small gap semiconducting organic charge-transfer interfaces

We investigated transport properties of organic heterointerfaces formed by single-crystals of two organic donor-acceptor molecules, tetramethyltetraselenafulvalene and 7,7,8,8-tetracyanoquinodimethane (TCNQ). Whereas the individual crystals have unmeasurably high resistance, the interface exhibits a resistivity of few tens of megohm with a...

Quantitative analysis of electronic transport through weakly coupled metal/organic interfaces

Using single-crystal transistors, we have performed a systematic experimental study of electronic transport through oxidized copper/rubrene interfaces as a function of temperature and bias. We find that the measurements can be quantitatively reproduced in terms of the thermionic emission theory for Schottky diodes, if the effect of the bias...

Bias-dependent contact resistance in rubrene single-crystal field-effect transistors

The authors report a systematic study of the bias-dependent contact resistance in rubrene single-crystal field-effect transistors with Ni, Co, Cu, Au, and Pt electrodes. They show that the reproducibility in the values of contact resistance strongly depends on the metal, ranging from a factor of 2 for Ni to more than three orders of magnitude...

Electrical transport measurements on self-assembled organic molecular wires

The electrical properties of supermolecular assemblies of oligo(p-phenylene vinylene) were studied. These materials self-assemble into well-defined cylindrical structures in solution with lengths in the range of 100?nm–10??m and diameters between 5 and 200?nm. Atomic force microscopy showed that by adjusting the concentration, either individual...

Reproducible low contact resistance in rubrene single-crystal field-effect transistors with nickel electrodes

We have investigated the contact resistance of rubrene single-crystal field-effect transistors (FETs) with nickel electrodes by performing scaling experiments on devices with channel length ranging from 200 nm up to 300??m. We find that the contact resistance can be as low as 100???cm with narrowly spread fluctuations. For comparison, we have...

Ambipolar Cu- and Fe-phthalocyanine single-crystal field-effect transistors

We report the observation of ambipolar transport in field-effect transistors fabricated on single crystals of copper- and iron-phthalocyanine, using gold as a high work-function metal for the fabrication of source and drain electrodes. In these devices, the room-temperature mobility of holes reaches 0.3?cm2/V?s in both materials. The highest...

Influence of the gate leakage current on the stability of organic single-crystal field-effect transistors

We investigate the effect of a small leakage current through the gate insulator on the stability of organic single-crystal field-effect transistors (FETs). We find that, irrespective of the specific organic molecule and dielectric used, leakage current flowing through the gate insulator results in an irreversible degradation of the single...

Single-crystal organic field-effect transistors based on dibenzo-tetrathiafulvalene

We report on the fabrication and characterization of field-effect transistors based on single crystals of the organic semiconductor dibenzo-tetrathiafulvalene (DB-TTF). We demonstrate that it is possible to prepare very-good-quality DB-TTF crystals from solution. These devices show high field-effect mobilities typically in the range 0.1–1?cm2/V...

Influence of the gate dielectric on the mobility of rubrene single-crystal field-effect transistors

We have performed a comparative study of rubrene single-crystal field-effect transistors fabricated using different materials as gate insulator. For all materials, highly reproducible device characteristics are obtained. The achieved reproducibility permits one to observe that the mobility of the charge carriers systematically decreases with...

Field-effect transistors on tetracene single crystals

We report on the fabrication and electrical characterization of field-effect transistors at the surface of tetracene single crystals. We find that the mobility of these transistors reaches the room-temperature value of 0.4?cm2/V?s. The nonmonotonous temperature dependence of the mobility, its weak gate voltage dependence, as well as the...

Scaling behavior and parasitic series resistance in disordered organic field-effect transistors

The scaling behavior of the transfer characteristics of solution-processed disordered organic thin-film transistors with channel length is investigated. This is done for a variety of organic semiconductors in combination with gold injecting electrodes. From the channel-length dependence of the transistor resistance in the conducting ON-state, we...

Switch-on voltage in disordered organic field-effect transistors

The switch-on voltage for disordered organic field-effect transistors is defined as the flatband voltage, and is used as a characterization parameter. The transfer characteristics of the solution processed organic semiconductors pentacene, poly(2,5-thienylene vinylene) and poly(3-hexyl thiophene) are modeled as a function of temperature and gate...

Electrical transport in monolayers of phthalocyanine molecular wires and AFM imaging of a single wire bridging two electrodes