Metal-electrode-dependent negative photoconductance response of the nanoscale conducting filament in the SiO2-metal stack

Nanoscale resistance reset of the SiO2/M stack (where M=Cu, Ni, Ti, Al, p-type Si) was investigated via a conductive atomic force microscope (C-AFM). Visible-light illumination triggers a resistance reset for Ti, Al and p-type Si electrodes, however such a behavior is not always observed for the Cu and Ni electrodes. Conversely, electrical reset is possible for Cu and Ni, but not for the others. The observed variations in optical and electrical induced resistive switching behaviors may be caused by a metal-electrode-dependent conducting filament.