Electrical bistability and charge transport behavior in Au nanoparticle/poly(N-vinylcarbazole) hybrid memory devices

Polymer memory devices using poly(N-vinylcarbazole) (PVK) as the active layer, incorporated with various weight ratios (0, 0.083, and 0.2) of dodecanethiol capped gold nanoparticles (Au NPs), are investigated. Electrical bistability is demonstrated for all three PVK-based devices, regardless of Au-NP ratios. However, current fluctuation is observed during stress test for both zero (PVK-only) and Au NPs:PVK=0.2:1 devices, while good current stability is obtained for the Au NPs:PVK=0.083:1 device. Capacitance-frequency (C-f) curves present the comparable negative capacitance feature for all three devices in both high-conductivity (“on”) state and low-conductivity (“off”) state, indicating that the carrier transport is dominated by the PVK matrix. However, minor differences in the C-f curves are dependent on the weight ratios of Au NPs, and the connection is discussed.