A low temperature solution-processed ormosil film for low-voltage organic field-effect transistors

Abstract

A high performance, low operating voltage organic field effect transistor (OFET) has been fabricated by utilizing organically modified silicate (ormosil) based film as dielectric. The ormosil film is fabricated by a sol-gel method at low temperature (180 °C) and exhibits a high dielectric (k = 33), a smooth surface (Rq = 0.29 nm) and a low leakage current density (5 × 10−9 A cm−2 at −2 V). The ormosil film contains hydrophobic methyl (CH3) functional groups derived from methyltriethoxysilane (MTES) and these groups produce a surface with hydrophobic character and low surface energy for pentacene film growth. The OFET with the ormosil dielectric exhibits excellent performs with high mobility (0.80 cm2 V−1 s−1), low operating voltage (−1.5 V), low threshold voltage (−0.25 V) and low sub-threshold swing (192 mV dec−1). The result demonstrates that the ormosil film can be used as a high performance dielectric for OFETs, and provides a promising way for low power and low cost organic electronics.