Influence of electrical field dependent depletion at metal-polymer junctions on resistive switching of poly(N-vinylcarbazole) (PVK)-based memory devices

Polymer memory devices using Au nanoparticles (Au NPs) incorporated poly(N-vinylcarbazole) (PVK) as the active layer and Al films as the electrodes are investigated. The Al/PVK:Au NPs/Al devices exhibit electrical bistability, in the I-V characteristics and show a conductance difference ratio between the high-resistance state (HRS) and low-resistance state (LRS) by a factor of 10(5). Furthermore, the Au nanoparticle/PVK hybrid memory device can be programmed and exhibits excellent thermal stability up to 154 degrees C in ambient atmosphere. The current conduction is dominated by Schottky emission at HRS and exhibits Ohmic behavior at LRS. The dependence of the current conduction on temperature reveals the connection between the conduction character and the energy-band offsets at the metal (Al or Au)-PVK junctions. In addition, the resistive switching is correlated with the width of depletion region in PVK, which varies with the change of hole carrier concentration upon applying electrical field. (C) 2009 Elsevier B.V. All rights reserved.