X-ray absorption spectroscopy of Cu-doped WO3 films for use in electrochemical metallization cell memory

• Cu-doped WO3 films were prepared by DC magnetron sputtering.
• Local atomic and electronic structure was studied by X-ray absorption spectroscopy.
• In the as-prepared samples copper is mostly present in the metallic phase.
• Copper ions transfer into Cu+ upon annealing at 135 °C.

We have performed the first synchrotron radiation X-ray absorption spectroscopy (EXAFS/XANES) study of the local atomic and electronic structure around Cu and W ions in WO3/Cu/WO3/Si and WO3/Cu/Si multilayered structures, aimed for the application in the electrochemical metallization cell memory. The influence of low-temperature annealing at 135 °C has been investigated in details, and a structural model of Cu-doped WO3 films is proposed.