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.