Organic filed-effect transistor (OFETs) based on polycrystalline “octithiophene”
has been realized. The current-voltage characteristics at low drain voltage has been used to
derive the mobility of organic field effects transistors (OFETs). It appears that the data
must be corrected for the substantial source and drain contact resistance. The carrier
mobility is found to increase quasi linearly with gate voltage at room temperature. The
temperature dependent measurements show that the mobility is thermally activated and becomes
practically temperature independent at low temperatures. A model based on trapping
mechanism, in which it is assumed that charge transport is limited by grain boundaries, has
been used to describe the carrier mobility in polycrystalline “octithiophene” thin film
transistors measured at temperatures ranging from 10 K to 300 K
