Micro-imprinted prism substrate for self-aligned short channel organic transistors on a flexible substrate

Using a simple micro-imprinting process on flexible substrates, we demonstrate fabrication of self-aligned short channel organic thin film transistors (OTFTs) with significantly reduced parasitic capacitance. The surface topology resulting from the imprinted prism-like structures enables accurate alignment of both the gate and source-drain electrodes. The parasitic overlap capacitance was reduced by 80%, which enables twice higher transition frequency (f_T = 10.1 kHz) compared with conventional top-contact OTFT devices. The prism-OTFTs were applied to both p-type (pentacene) and n-type (C60) organic semiconductors to implement low voltage complementary inverters.