STUDY OF ORGANIC THIN FILM TRANSISTOR WITH PHOTOPATTERNED GATE DIELECTRIC

In order to investigate the feasibility of gating organic field-effect transistors (OFETs) using a photosensitive photoresist material, pentacene-based OFETs were fabricated on indium tin oxide (ITO) glass. The gate dielectric was found to be easily patterned by spin coating and UV exposure, and has an excellent surface roughness of 0.22 nm and good insulating properties, resulting in a low leakage current (49 nA at 2 MV/cm) at a dielectric thickness of 290 nm. The OFET with photopatterned gate dielectric exhibited good electric characteristics, including a high field-effect mobility of 0.15 cm(2)/Vs, a threshold voltage of -9.9 V, and on/off current ratio of similar to 10(4). The high matching of surface free energy between the gate dielectric and pentacene is proved to be contributed to the good performance of the device.