科研之友
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摘要
Organic thin-film transistors (OTFTs) and other organic electronic devices have attracted more and more attention for next-generation wearable and flexible devices. Because of low conductivity of organic materials, working OTFTs need a channel structure with a very large aspect ratio (or ratio between channel width and length) to enable a sizable drive current. Therefore, to produce densely arranged OTFTs with microscale footprint areas, the OTFT channel length needs to be scaled down to sub-100 nm regimes. To enable cost-effective manufacturing of such nanoscale OTFT arrays, solvent-processing methods, such as spin-coating and roll-to-roll coating, are highly desirable, but such processes inevitably result in air voids in nanoscale OTFT channels, leading to poor and inconsistent gate modulation characteristics. In this work, the authors reveal the nanofluidic mechanisms responsible for the formation of air voids through characterizing the cross-sectional morphologies of as-fabricated nanoscale OTFT channels using electron microscopy and simulating the nanofluidic flows of organic materials into nanoscale transistor channel gaps using a computational fluidic dynamics tool. This work suggests that a post-fabrication thermal pressing process is needed for eliminating air voids and significantly improving gate modulation characteristics. Using this process, the authors demonstrate poly(3-hexylthiophene) OTFT arrays with channel length of 66 nm, which exhibits highly consistent on/off ratios up to similar to 10(6). This work advances the technical and scientific knowledge for processing solution-based organic electronic materials into nanoscale devices. The presented thermal pressing process can be generically implemented for processing a broad range of solution-based organic materials.
- 出版日期2017-11
