Solution-processed highly efficient Au nanoparticles and their reduced graphene oxide nanocomposites as charge trapping media for ZnO thin film transistor nonvolatile memory

Abstract

Solution-processed, non-volatile undoped and Hf-doped ZnO thin film transistor (TFT) memory was demonstrated by inserting gold nanoparticles (AuNPs) and AuNPs reduced graphene oxide (AuNPs-rGO) nanocomposite charge trapping media between undoped and Hf-doped ZnO and SiO2 dielectrics. The one step reduction and decoration of graphene oxide with AuNPs to create the nanocomposites used thermostable Nisin peptides. Undoped and Hf-doped ZnO TFT memory devices made with AuNPs and AuNPs-rGO exhibited large gate bias-dependent clockwise hysteresis windows. The memory devices exhibited excellent programmable windows of up to 40 V during program/erase operations. This is attributed to trapping and de-trapping of charge carriers by the AuNPs and the AuNPs-rGO nanocomposites. The resulting memory devices exhibited remarkable long-term retention characteristics. Hf-doped ZnO TFT memory devices made with AuNPs or AuNPs-rGO nanocomposites exhibited higher ON/OFF ratios than those made with undoped ZnO. The memory devices made with AuNPs-rGO nanocomposites exhibited ON/OFF ratios greater than 104.