Abstract
Complementary thin-film transistor circuits composed of 6,13-bis(triisopropyl-silylethynyl) pentacene (TIPS-PEN) and a rylene carboxylic diimide derivative for p- and n-channel thin-film transistors (TFTs) were fabricated on flexible foils. The so-called staggered TFT configuration is used, meaning that the semiconductors layers are deposited last. The work-function of the injecting gold electrodes were modified using several self-assembled monolayers (SAMs). For optimized contacts the mobility of the n- and p-channel TFTs was 0.5 cm2/Vs and 0.2 cm2/Vs, respectively. Strongly degraded performance is obtained when the n-channel material was printed on contacts optimized for the p-channel TFT, and vice versa. This illustrates that for CMOS circuits we need careful work-function engineering to allow proper injection for both electrons and holes. We show for the first time that by using a bimolecular mixture for the SAM we can systematically vary the work function, and demonstrate how this affects the performance of discrete n-type and p-type transistors, as well as CMOS inverters and ring oscillators. Under optimal processing conditions we realized complementary 19-stage ring oscillators with 10 μs stage delay operating at 20 V.
Original language | English (US) |
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Pages (from-to) | 1686-1692 |
Number of pages | 7 |
Journal | Organic Electronics |
Volume | 13 |
Issue number | 9 |
DOIs | |
State | Published - Sep 2012 |
Funding
The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007-2013) under Grant agreement No. 247681 of the COSMIC project.
Keywords
- Complementary circuits
- Contact injection
- Contact modification
- Energy delay product
- Ink-jet printing
- Organic transistor
- Self-assembled monolayers
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- General Chemistry
- Condensed Matter Physics
- Materials Chemistry
- Electrical and Electronic Engineering
- Biomaterials