High-Mobility Field-Effect Transistors from Large-Area Solution-Grown Aligned C₆₀ Single Crystals

TLDR

Field‑effect transistors based on single‑crystal organic semiconductors achieve the highest reported charge‑carrier mobilities, yet fabricating dense, aligned crystal arrays over large areas remains challenging. The authors aim to grow large arrays of aligned C(60) single crystals. They employ a solution‑processing method to achieve this growth. The resulting aligned C(60) single‑crystal needles and ribbons reach electron mobilities up to 11 cm² V⁻¹ s⁻¹—about eight times higher than the best solution‑grown n‑channel organic materials and twice the highest mobility of any n‑channel organic material—and the method scales to 100 mm wafers with ~50 % surface coverage, enabling large‑area single‑crystal applications.

Abstract

Field-effect transistors based on single crystals of organic semiconductors have the highest reported charge carrier mobility among organic materials, demonstrating great potential of organic semiconductors for electronic applications. However, single-crystal devices are difficult to fabricate. One of the biggest challenges is to prepare dense arrays of single crystals over large-area substrates with controlled alignment. Here, we describe a solution processing method to grow large arrays of aligned C(60) single crystals. Our well-aligned C(60) single-crystal needles and ribbons show electron mobility as high as 11 cm(2)V(-1)s(-1) (average mobility: 5.2 ± 2.1 cm(2)V(-1)s(-1) from needles; 3.0 ± 0.87 cm(2)V(-1)s(-1) from ribbons). This observed mobility is ~8-fold higher than the maximum reported mobility for solution-grown n-channel organic materials (1.5 cm(2)V(-1)s(-1)) and is ~2-fold higher than the highest mobility of any n-channel organic material (~6 cm(2)V(-1)s(-1)). Furthermore, our deposition method is scalable to a 100 mm wafer substrate, with around 50% of the wafer surface covered by aligned crystals. Hence, our method facilitates the fabrication of large amounts of high-quality semiconductor crystals for fundamental studies, and with substantial improvement on the surface coverage of crystals, this method might be suitable for large-area applications based on single crystals of organic semiconductors.