Low-voltage high-performance C60 thin film transistors via low-surface-energy phosphonic acid monolayer/hafnium oxide hybrid dielectric

C60 -based organic thin film transistors (OTFTs) have been fabricated using a n -octadecylphosphonic acid self-assembled monolayer/sol-gel processed hafnium oxide hybrid dielectric. With the combination of high capacitance (580 nF/ cm2) and low leakage current density (8× 10-9 A/ cm2), this hybrid dielectric yields C60 OTFTs operating under 1.5 V with an average n -channel saturation field-effect mobility of 0.28 cm2 /V s, high on-off current ratio of 105, and low subthreshold slope of 100 mV/decade. The low surface energy of the n -octadecylphosphonic acid allows C60 to form a thin film with large grains that provide an efficient charge carrier pathway for the low-voltage OTFTs. © 2008 American Institute of Physics.