Low-frequency noise in polymer transistors

The low-frequency noise (LFN) properties of field-effect transistors (FETs) using polymers as the semiconducting substrate material are investigated and explained in terms of the nonstationary mobility /spl mu/ in the semiconducting polymer. In the frequency (f) range f<1 kHz it was found that 1/f noise prevails over other types of LFN in these polymer FETs (PFETs). The spectral density S/sub I/ of LFN of the drain current ID is proportional to the DC power V/sub DS//spl middot/I/sub D/ applied to the PFETs channel, from the ohmic to the saturation modes of device operation. In addition, S/sub I/ is affected by the carrier mobility /spl mu/ in PFETs channel, as /spl mu/ in organic FETs is dependent on the biasing. Thus, SI can have an additional sensitivity to I/sub D/, that is, S/sub I//spl prop/(V/sub DS//spl middot/I/sub D/)/sup 1-k/, where k/spl sim/0.1. In general, the 1/f LFN of PFETs follows the relations that have been obtained for crystal and inorganic FETs with minor correction for nonstationary mobility /spl mu/.