Nonvolatile Memory Effect in a Au/Cu–ZnO/p-Si Type of Metal–Insulator–Semiconductor Structure

A low-cost insulating Cu-doped ZnO (Cu-ZnO) thin film has been utilized to form a Au/Cu-ZnO/p-Si type of metal-insulator-semiconductor (MIS) junction. The capacitance-voltage plot shows a nonvolatile memory effect through an anticlockwise hysteresis loop, indicating electron trapping and detrapping. The area of the hysteresis loop and the saturated capacitance value is found to be dependent on the frequency, indicating involvement of various trap states. A possible mechanism corresponding to the "writing" and "erasing" processes for the MIS structure has been discussed. The memory effect of the Cu-ZnO-based MIS device is novel and uniquely unconventional that we are reporting for the first time.