Memory devices based on functionalized copolymers exhibiting a linear dependence of switch threshold voltage with the pendant nitro-azobenzene moiety content change

A nonvolatile nanoscale memory device based on pendent copolymer exhibits write-once-read-many-times (WORM) characteristics with the highest ON/OFF current ratio up to 10(4) and a long retention time. Moreover, it was observed that switch threshold voltages of the device varied almost linearly with the functional moiety content in the copolymer. The cyclic voltammetry (CV) curves and UV-vis spectra of the copolymer's nanofilms were investigated and the obtained results associated with the linear decreasing memory behavior. The mechanisms of the device exhibiting WORM characteristics were elucidated from molecular simulation results showing that the electron density transition from the HOMO to LUMO surfaces is permanently under electric field and would not revert to the original state after the external voltage was removed.