Memory properties of Au nanoparticles prepared by tuning HAuCl4 concentration using low-temperature hydrothermal reaction

Abstract

An organic memory device with embedded gold nanoparticles (AuNPs) as charge storage elements and polymethylsilsesquioxane (PMSSQ) as organic dielectric layer was fabricated in this work. The AuNPs were prepared using sacrificial hydrothermal reaction on Al template, and the effect of HAuCl4 on size of AuNPs was studied. Field-emission scanning electron microscopy confirmed the increase of particle size with the increase in HAuCl4 concentration. X-ray diffraction analysis confirmed the formation of AuNPs with face-centered cubic (FCC) structure. The electrical properties of the memory system were investigated using a semiconductor characterization system. Current–voltage analysis confirmed the nonvolatile electrical bistability behavior and charge transport mechanism. Capacitance–voltage measurement indicated a memory behavior with flatband voltage shift because the AuNPs trapped and stored charges in the device. The optimal memory properties of AuNPs embedded in PMSSQ were obtained for FCC-structured AuNPs grown in 0.010 M HAuCl4, with a mixture of 82 ± 5 nm (area density, 1.3 × 1012 m− 2) and 42 ± 7 nm (area density, 2.7 × 1012 m− 2) grain sizes that produced the lowest switch ON voltage of 2.2 V and highest flatband voltage of 2.6 V.