C₆₀ thin-film transistors with high field-effect mobility, fabricated by molecular beam deposition

We report performance of C₆₀ thin-film field-effect transistors and characterizations of C₆₀ thin-films on SiO₂ substrates fabricated by molecular beam deposition. Devices, fabricated and characterized under high vacuum without exposing to air, routinely showed current on/off ratios > 10⁸ and field-effect mobility in the range of 0.5-0.3 cm²/Vs. The obtained mobility is comparable to the highest value among n-type organic thin-film transistors and close to that derived from the photocurrent measurements on C₆₀ thin-films. The grain size of C₆₀ thin-film, condensed in an fcc solid, increases with the substrate temperature, while the mobility did not exhibit a clear relation with substrate temperature.