  We investigated the reversible resistive switching of
poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) thin films
sandwiched between Al electrodes. The J-V sweep curve showed a hysteretic
behavior which depends on the polarity of the applied voltage bias. From the
analysis of I-V curves, it was revealed that the charge transport through the
junction was governed by the bulk space-charge-limited conduction (SCLC) model.
Using transmission electron microscopy (TEM) analysis, it was confirmed that
the initial high resistance state of PEDOT:PSS films is related with the
segregation of PSS- chains induced by redox reaction between a Al metal
electrode and PEDOT:PSS film. Positive space charges present on the top region
of PEDOT:PSS films can be proposed as a possible trap centers of electron
trapping and detrapping process.
