Sci. Adv. 4, eaao5758 (2018)

The low-temperature growth of high-quality large-scale 2D organic single crystals is a prerequisite for the development of low-cost, high-yield organic nanoelectronic devices and circuits. Despite several recent demonstrations of ultrathin large-area organic single crystals, the realization of monolayer wafer-scale sheets has never before been reported. Now, using a well-established low-temperature fabrication technique, Yamamura et al. reveal a simple growth method that can further promote the scaling-up of uniform high-mobility organic semiconductors for high-speed electronic circuits.

Organic crystalline films of C8-DNBDT-NW were fabricated via a meniscus-driven solution method, also known as continuous edge casting, at the optimized substrate temperature and shearing speed. With only two parameters to control during the one-shot growth procedure, the resulting thickness of the films can be precisely tuned from a mono- or bilayer to a few layers. Taking advantage of the large size of the crystalline films, the authors demonstrate several hundreds of transistors with uniform all-around performance. The high quality of the fabricated films is further exemplified by the champion bilayer transistor that exhibits a channel carrier mobility of 13 cm2 V−1 s−1, high switching speed and low-voltage operation.