Solution-grown aligned C60 single-crystals for field-effect transistors

Single crystals of C-60 have been widely prepared previously. However, their electronic properties are much less frequently studied, although C-60 is known as an outstanding electronic material. Also, the reported electron mobility values (similar to 10(-2) cm(2) V-1 s(-1)) of C-60 single-crystals are unexpectedly low possibly due to the difficulties in the fabrication of single-crystal devices. We have recently reported a droplet receding method for the solution-grown C-60 single-crystals with mobilities above 1 cm(2) V-1 s(-1). In this work, we systematically investigate the effects of solvent and surface properties of the substrate on the growth of C-60 single-crystals. Well-aligned C-60 needle-like and ribbon-like single-crystals were grown from suitable solvents (m-xylene or a mixed solvent of m-xylene and carbon tetrachloride) conformally on the field-effect transistor (FET) substrates that were wet well by the receding droplet. Based on the ribbonlike single-crystals, an average electron mobility of 2.0 +/- 0.61 cm(2) V-1 s(-1), I-on//I-off > 10(6), and a VT between 36 and 85 V were achieved from 60 field-effect transistors. Insights provided by this work may help accelerate the development of solution-grown single-crystals of organic semiconductors.