Covalent assembly of gold nanoparticles for nonvolatile memory applications

This work reports a versatile approach for enhancing the stability of nonvolatile memory devices through covalent assembly of functionalized gold nanoparticles. 11-mercapto-1-undecanol functionalized gold nanoparticles (AuNPs) with a narrow size distribution and particle size of about 5 nm were synthesized. Then, the AuNPs were immobilized on a SiO ₂ substrate using a functionalized polymer as a surface modifier. Microscopic and spectroscopic techniques were used to characterize the AuNPs and their morphology before and after immobilization. Finally, a metal-insulator- semiconductor (MIS) type memory device with such covalently anchored AuNPs as a charge trapping layer was fabricated. The MIS structure showed well-defined counterclockwise C-V hysteresis curves indicating a good memory effect. The flat band voltage shift was 1.64 V at a swapping voltage between ±7 V. Furthermore, the MIS structure showed a good retention characteristic up to 20 000 s. The present synthetic route to covalently immobilize gold nanoparticles system will be a step towards realization for the nanoparticle-based electronic devices and related applications.