In this work, a tungsten oxide (WOx) film is prepared using a thiourea-assisted solution process. We demonstrate a device composed of fluorine doped tin oxide (FTO)-glass/WOx/electrolyte/indium-tin oxide (ITO)-glass stacking electrochromic (EC) structure and Al electrodes that are locally patterned and interposed between the WOx film and electrolyte, which form an Al(top electrode)/WOx/FTO(bottom electrode) resistance random access memory (RRAM) unit. According to transmission electron microscopy and X-ray photoelectron spectroscopy analyses, the WOx film contains nanosize pores and metallic-tungsten nanoclusters which are scattered within the tungsten oxide layer and concentrated along the interface between the Al electrode and WOx film. With application of voltage to the ITO electrode, multiple transmittance states are achieved for the EC unit due to the different quantity of intercalated Li ions in the WOx film. As for the Al/WO x/FTO RRAM unit, a bipolar nonvolatile resistive switching behavior is attained by applying voltage on the Al top electrode, showing electrical bistability with an ON/OFF current ratio up to 1 × 104.
All Science Journal Classification (ASJC) codes
- Materials Science(all)