In this study, Si-nanoparticle(NP)/Si-nanowire(NW)-based field-effect transistors (FETs) with a top-gate geometry were fabricated and characterized. In these FETs, Si NPs were embedded as localized trap sites in Al2O3 top-gate layers coated on Si NW channels. Drain current versus drain voltage (I-DS-V-DS) and drain current versus gate voltage (I-DS-V-GS) were measured for the Si NP/Si NW-based FETs to investigate their electrical and memory characteristics. The Si NW channels were depleted at V-GS = 9 V, indicating that the devices functioned as p-type depletion-mode FETs. The top-gate Si NW-based FETs decorated with Si NPs show counterclockwise hysteresis loops in the I-DS-V-GS curves, revealing their significant charge storage effect.