Organic thin film transistors with HfO2 high-k gate dielectric grown by anodic oxidation or deposited by sol–gel

We report here on pentacene based organic field effect transistors (OFETs) with a high-k HfO₂ gate oxide. HfO₂ layers were prepared by two different methods: anodic oxidation and sol–gel. A comparison of the two processes on the electrical properties of OFETs is given. Ultra thin nanoporous (20 nm) sol–gel deposited oxide films were obtained following an annealing at 450 °C. They lead to high mobility and stable devices (μ = 0.12 cm²/V s). On the other hand, devices with anodic HfO₂ revealed a little bit more leaky and show some hysteresis. Anodization, however, presents the advantage of being a fully room temperature process, compatible with plastic substrates. Stability and response to a bias stress are also reported.     

Khaya gum – a natural and eco-friendly biopolymer dielectric for low-cost organic field-effect transistors (OFETs)

Journal of Materials Science: Materials in Electronics - Nature provides a wide range of dielectric biopolymers that can be used in electronic devices. In this work, organic field-effect...     

Stability and 2,4-dinitrotoluene response of organic field effect transistors based on π-conjugated thiophene oligomers

This paper reports on organic field effect transistors (OFETs) based on two π-conjugated oligomers derived from thiophenes and their use as sensors for the detection of 2,4-dinitrotoluene (DNT). The detection mechanism relies on donor-acceptor interactions between the π-conjugated system (donor) and the nitrated molecule (acceptor). An important feature of sensors is the stability under operation, so, a large part of this work will be dealing with the behavior of OFETs under bias stress experiments as well as with the influence of temperature during operation. Most of results reported here are concerning hexyl capped tetra Thienylene–Vinylene (denominated 4-TV). Some preliminary results on the promising hexyl capped quinquethiophene derived from 3,4-ethylenedioxythiophene (denominated TETET) are also reported. Under a DNT contaminated air atmosphere ( 7 ppm), 4-TV based OFETs exhibit an increase of the drain current when DNT is present in the atmosphere as expected.