GAS-SENSITIVE AND TEMPERATURE-DEPENDENT SCHOTTKY-GATED FIELD-EFFECT TRANSISTORS UTILIZING POLY(3-ALKYLTHIOPHENE)S

Gas-sensitive and temperature dependent poly(3-alkylthiophene) field e ffect transistors (FET) have been investigated. The FET shows typical enhancement type metal-semiconductor FET characteristics. Gas sensitiv ity of poly(3-butylthiophene) has been investigated for air, water vap or, ethanol and chloroform gases. These gases show enhancement of sour ce-drain current compared with that in vacuum. The enhancement of sour ce-drain current in chloroform gas shows the largest compared with oth er gases. The temperature dependence of poly(3-ethylthiophene) shows i ncrease in source-drain current as increasing temperature, which is ma inly due to the increase in carrier mobility. All these changes are re versible. Other poly(3-alkylthiophene)s which have different alkyl-sid e-chain length have also been discussed.