Operating mechanisms of highly-reproducible write-once-read-many-times memory devices based on graphene quantum dot: poly(methyl silsesquioxane) nanocomposites

Abstract

Resistive switching memory devices were fabricated utilizing graphene quantum dot (GQD):poly(methyl silsesquioxane) (PMSSQ) hybrid nanocomposites. Current-voltage curves for the Al/GQD:PMSSQ/indium-tin-oxide devices at room temperature showed write-once-read-many-times memory (WORM) characteristics with an ON/OFF ratio of as large as 106 due to the homogeneous dispersion of the GQDs in the PMSSQ matrix. The WORM devices maintained retention times larger than 2 × 104 s under ambient conditions. The devices showed high device-to-device reproducibility with threshold-voltage distributions between 3 and 5 V. The ON state currents remained between 10-6 and 10-3 A, and the OFF state currents maintained between 10-12 and 10-9 A. The operating mechanisms concerning the interaction between the GQDs and the PMSSQ matrix for the resistive-switch phenomenon were analyzed on the basis of the I-V results and with the aid of the energy band diagram.