Electrical properties and operating mechanisms of nonvolatile organic memory devices fabricated utilizing hybrid poly(N-vinylcarbazole) and C-60 composites

Abstract

Organic memory devices based on hybrid poly(N-vinylcarbazole) (PVK) and C-60 composites were fabricated with a spin-coating method. Atomic force microscopy images showed that the surface of the PVK layer containing the C-60 molecules was relatively smooth. Capacitance-voltage (C-V) measurements on the Al/C-60 embedded in PVK layer/p-Si(100) device at room temperature showed a clockwise hysteresis with a large flatband voltage shift due to the existence of the C-60 molecules in the PVK layer, indicative of charge storage in the embedded C-60 molecules. The clockwise direction of the C-V hysteresis for the devices was attributed to carrier tunneling through the PVK layer emitting from the Al gate electrode, and the negative and positive flatband voltage shifts of the C-V curves originated from the holes and electrons captured in the C-60 molecules, respectively. Possible operating mechanisms corresponding to writing and erasing processes for the Al/C-60 embedded in PVK layer/p-Si (100) device are described on the basis of the C-V results.