Quantitative analysis of O2 gas sensing characteristics of picene thin film field-effect transistors

O2 gas sensing behaviors are studied in picene thin film field-effect transistors (FETs) with hydrophobic polymer (Cytop™ or polystyrene) coated SiO2 gate dielectrics. Picene thin film FETs show a rapid reduction of hysteresis in transfer curves recorded in forward and reverse measurement modes, compared to a picene FET with hexamethydisilazane-coated SiO2. The picene FETs show very sensitive O2 gas sensing effects down to ∼10 ppm. A quantitative analysis is presented of the gate voltage (VG) dependent mobility induced by O2 exposure, i.e., the suppression of drain current at high VG.