RRAMs with Organic/Polymer Films Blended with Nanoparticles

Abstract

RRAMs with composites of organic or polymeric materials and NPs were developed as the combination of organic electronics and nanoelectronics. Conjugated organic molecules and polymers are considered as organic semiconductors, because the conjugated π electronics are delocalized [1, 2]. When in the neutral state, these materials usually have low conductivity. Their conductivity can be significantly increased after oxidation or reduction. For example, charge-transfer complexes of tetracyanoquinodimethane (TCNQ) can have a conductivity of up to 102 S cm−1, in which TCNQ is an electron acceptor and is negatively charged in the complexes [3, 4]. Because of the nanometer size, charges can be trapped on NPs. When NPs are mixed with an organic or polymeric semiconductor, the charge trapping on the NPs can affect the electronic structure and the conductivity of the organic semiconductor. This can give rise to resistive switch. In terms of the device architecture, there are two types of organic and polymer RRAMs with charge trapping NPs, one with a triple layer structure while another with a single layer structure between two electrodes [5–9]. The chemical structures of some organic molecules and polymers used in organic and polymer RRAMs are listed in Fig. 2.1.