Dirk Dr. Rohde

Flexible organic complementary circuits

We report the first organic complementary circuits on flexible substrates. Organic thin-film transistors were fabricated using pentacene as the semiconductor for the p-channel devices and hexadecafluorocopperphthalocyanine (F/sub 16/CuPc) as the semiconductor for the n-channel devices. Both semiconductors were purchased from commercial sources and deposited by evaporation in vacuum. The pentacene layer was photolithographically patterned to simplify the circuit layout and reduce the circuit area. The transistors and circuits were manufactured on thin, transparent sheets of polyethylene naphthalate. Evaporated metals were used to define all contacts and interconnects, and a 50-nm-thick layer of solution-processed polyvinylphenol was used as the gate dielectric. Transistors and circuits operate at supply voltages as low as 8 V, and ring oscillators have a signal propagation delay as low as 8 /spl mu/s per stage. To our knowledge, these are the fastest organic complementary circuits reported to date.