Manufacturing and characteristics of low-voltage organic thin-film transistors

Organic thin-film transistors (TFTs) are field-effect transistors in which the semiconductor is a more or less ordered (usually polycrystalline) film of conjugated organic molecules. The channel mobility of organic TFTs is usually in the range of 0.1 to 1 cm²/Vs, and the cutoff frequency is typically between 10 kHz and 1 MHz. Organic TFTs can be fabricated at relatively low temperatures of about 100°C and thus on flexible plastic substrates and even on paper. To keep the gate leakage through the low-temperature-deposited gate dielectric small, the dielectric is usually relatively thick, so that organic TFTs typically require relatively large voltages (≥10 V). Recently, a monolayer-based dielectric with a thickness of only a few nanometers that provides both a large capacitance and small gate leakage has allowed the fabrication of organic TFTs and organic complementary circuits that can be operated with voltages of about 2 to 3 V.