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 μ 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_I of LFN of the drain current ID is proportional to the DC power V_DS·I_D applied to the PFETs channel, from the ohmic to the saturation modes of device operation. In addition, S _I is affected by the carrier mobility μ in PFETs channel, as μ in organic FETs is dependent on the biasing. Thus, SI can have an additional sensitivity to I_D, that is, S_I∝(V_DS·I_D)^1-k, where k~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 μ