Oxygen-concentration effect on p-type CuAlOx resistive switching behaviors and the nature of conducting filaments

Resistive-switching (RS) memories with good performance and flexibility are demonstrated in p-type amorphous CuAlOx. The nature of conducting filaments (CFs) is studied via the dependence of RS behaviors on the oxygen concentration of CuAlOx. It is observed that with increasing oxygen concentration, (1) both resistance-states and switching-voltages reduce, showing an opposite trend to popular n-type oxide devices; and (2) a transition from non-degenerate to degenerate states occurs in CFs. These observations indicate that the CFs are composed of Cu-vacancy shallow acceptors. The oxygen-concentration dependence of CFs' resistance results from the change of Cu-vacancy content, rather than CFs' size or number.