Mobility saturation in tapered edge bottom contact copper phthalocyanine thin film transistors

Copper phthalocyanine (CuPc) thin film transistors were fabricated using a tapered edge bottom contact device geometry, and mobility saturation was observed for devices with CuPc thicknesses of 12 monolayers (MLs) and greater. The mobility saturation is attributed to a significantly decreased contact resistance resulting from a bilayer resist lift-off method, as compared with a single layer resist lift-off method. Threshold voltages are also found to saturate above 12 ML CuPc thicknesses.