High-performance non-volatile memory devices from metallomacrocyclic organic micro/nanostructure: Control via molecular manipulation

Abstract

Here, we report the synthesis of micro/nanostructures of a metal-macrocyclic organic compound, viz, Iron phthalocyanine (FePc) via cost-effective solvothermal method and consequent fabrication of high-performance resistive memory devices from FePc micro/nanorod embedded in poly(methyl methacrylate) (PMMA) matrix. The devices exhibited bipolar and non-volatile resistive switching characteristics. Interestingly, the performances of the devices (On/Off current ratio) improved by several orders of magnitude when an additional buffer layer of PMMA was deposited prior to the deposition of the active film (FePc embedded in PMMA). The variation in thickness of the PMMA buffer layer indicated that at an optimum thickness ca. 15 nm, the best performances were obtained with switching (Set) voltage ca. 1.6 V, On/Off current ratio ∼ 106 and retention ability of more than 10 h. The conduction mechanism has been discussed by linear fitting of the characteristics curves in both low and high resistance states of the device. The analysis lead to the conclusion that trapping/detrapping of charge carriers at the redox and defect sites within the active film (FePc embedded in PMMA) and at the PMMA-FePc/PMMA interface resulted in the resistive switching of the device and a trap induced space charge limited current was found to dominate in the Off- and On-state of the device.