Liquid/Liquid Interfacial Assembly of Poly(methyl methacrylate)-Grafted Nanoparticles into Superlattice Monolayers...

Polymer/gold nanoparticle (AuNP) composites have been utilized as floating gates to enhance the performance of memory devices. However, these devices typically exhibit a low ON/OFF drain current ratio (I_ON/I_OFF) and unstable charge trapping, attributed to the poorly defined arrangement of AuNPs within the composite floating gate. To address these limitations, this study employs poly(methyl methacrylate)-grafted AuNPs (Au@PMMA) as building blocks for the fabrication of monolayered superlattice films with a highly ordered structure via liquid/liquid interfacial assembly. A centimeter-scale superlattice monolayer was successfully achieved, effectively overcoming the challenges associated with the uneven distribution of Au@PMMA at the liquid/liquid interface. These superlattice monolayers were then used as floating gates to construct nanofloating-gate memory (NFGM) devices based on a field-effect transistor architecture. The influence of the Au@PMMA arrangement on the performance of the memory devices was systematically investigated. The resulting superlattice NFGMs demonstrated a stable I_ON/I_OFF ratio of 10³ for at least 10⁴ seconds, a memory window of 60 V, and robust endurance over 100 programming/reading/erasing/reading cycles, significantly outperforming traditional devices with disordered floating-gate layers.