Highly improved charge injection in pentacene-based organic transistors by chemically doping with copper iodide interlayer

Abstract

We have fabricated pentacene‐based transistors by inserting an ultrathin copper iodide (CuI) layer between the semiconductor and Cu electrodes, which exhibits an enhanced field effect mobilities from 0.39 to 1.27 cm2 Vs−1 as compared to those with the conventional Au electrodes. The enhancements are attributed to the significantly reduced contact resistance, which is believed to originate from a more favorable energy level alignment and better contact properties by introducing the CuI layer. Moreover, charge‐transfer complexes formed at the interface of the CuI and pentacene are also considered to be responsible for the improved field effect mobility. The experimentally observed results provide an appealing alternative for the optimization of the performance of OFETs with low‐cost electrodes.

Comparison of organic and inorganic layers for structural templating of pentacene thin films

“…Grain sizes of 69 ± 35 nm were observed agreeing well with literature describing the formation of smooth layers at room temperature ( Figure 1d). 47 At 200°C, CuI is known to form discontinuous layers due to an island growth 32 and therefore to ensure full coverage of the substrate, the film was initially grown to a thickness of 50 nm. Although larger gain sizes were observed, pinholes were visible in the film indicating incomplete layer growth (Figure 1e).…”

Solution processable high quality ZrO2dielectric films for low operation voltage and flexible organic thin film transistor applications

“…Finally, a 40 nm thick Cu source/drain (S/D) electrode was thermally evaporated on the pentacene layer with a shadow mask, which finally defined a bottomgate and topcontact OTFT device with channel width/length of 750 µm/50 µm. The main consideration for us to choose Cu as the S/D electrodes is that it can provide a reduced contact resistance between the S/D electrode and pentacene and enhanced carrier mobility in the channel when compared with that of Au electrodes [28,29].…”

Facile Synthesis of Solution-Processed Silica and Polyvinyl Phenol Hybrid Dielectric for Flexible Organic Transistors

“…As we know, the surface properties and the dielectric constant (k) of gate insulators play a dominant role in threshold voltage. The surface properties have a strong influence on the trap-state density related to the threshold voltage [5,6]. The k value of a gate insulator directly determines the capacitance value, which leads to the change of threshold voltage [7].…”