Authors: J.H. Zhao, R.G. Pillai, M.S. Freund, D.J. Thomson
Affilation: University of Manitoba, Canada
Pages: 65 - 68
Keywords: polymer, memory
In this report, a conjugated semiconducting polymer composite was designed to have a mobile charge carrier density that can be controlled through an electric field. An electrochemically deposited polypyrrole (PPy) composite between two gold electrodes contains large immobile anions (DBS-). These anions act as counterions for the oxidized (conducting) form of the polymer. Small highly mobile cations (Li+) balance the charge of the immobile anions in the reduced (semiconducting) polymer (PPy0(DBS-Li+)). Application of an electric field across the (PPy0(DBS-Li+)) composite junction should result in the drift of Li+ ions that introduces holes to form PPy+(DBS-). The introduction of holes produces regions of higher conductivity and has the overall effect of increasing the current flowing through the junction. The field modulated carrier redistribution results in field and time dependent behavior that has been used to implement a novel memory. The memory has been demonstrated in a crossbar junction configuration. This composite polymer system promises better scaling in nanometer-scale electronics due to space charge limited currents. The devices are electrochemically deposited after all metal layers have been fabricated and should have enhanced compatibility with standard CMOS circuits.
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