Study of the influences of molecular planarity and aluminum evaporation rate on the performances of electrical memory devices

Abstract

In this paper, two conjugated small molecules (CZ-BT and TPA-BT) were designed and successfully synthesized to investigate the influence of different electron donor moieties on thin-film morphology and their electrical memory device properties. Current–voltage (I–V) curves indicated that both CZ-BT and TPA-BT exhibited stable dynamic random access memory (DRAM) characteristics under appropriate Al evaporation rate condition, but with different threshold voltages, the former lower than the latter due to its better film morphology and closer intermolecular stacking. Furthermore, the performances of the two devices under different Al electrode evaporation rates was also investigated, and the results showed that the CZ-BT-based device still exhibited original DRAM characteristics, whereas the TPA-BT-based device exhibited WORM characteristic when Al electrode evaporation rate was increased to 5 Å s⁻¹. The variation of storage characteristics of TPA-BT could be mainly attributed to its poor film-forming property, and the Al nano-particles would penetrate into the film during the quick evaporation process to form filamentary conduction leading to WORM behavior.