Self-alignment organic field-effect transistors with silver nanoparticle electrodes

Self-alignment organic field-effect transistors with silver nanoparticle electrodes fabricated using the back-surface exposure method were investigated. Using a thick silver (Ag) nanoparticle (NP) gate electrode as a photomask, a photoresist on thin and semitransparent Ag NP source and drain electrodes was patterned by back-surface exposure. Transmittances of thick (1,600 A) and thin (400 A) Ag NPs were 0.75 and 18.0%, respectively. The overlap between the gate electrode and the photoresist pattern increased with the back-surface exposure time, and the resultant overlap length of the gate-source and gate-drain electrodes was 2 μm. For device characteristics, the field effect mobility, threshold voltage, and on-off ratio were 0.012 cm2/(V s), 12 V, and 1:5 × 103, respectively.