Bottom contact ambipolar organic thin film transistor and organic inverter based on C60/pentacene heterostructure

We report on the fabrication and characterization of the bottom contact organic thin film transistor and inverter based on a heterostructure of C-60 on pentacene. The transistor shows ambipolar transport characteristics with high electron and hole mobilities of 0.23 cm(2) V-1 s(-1) and 0.14 cm(2) V-1 s(-1), respectively. Both the n-channel in C-60 and the p-channel in pentacene are stable in N-2 atmosphere. After exposure to air, the n-channel is completely degraded whereas the p-channel keeps working. The inverter exhibits typical transfer characteristics, which are interpreted by the distribution of the accumulated electrons and holes depending on the bias conditions. The combination of the high performance and the bottom configuration of our devices suggests a potential way to fabricate organic complementary circuits without patterning of organic materials. (c) 2006 Elsevier B.V. All rights reserved.