Improved resistive switching characteristics in the p+-Si/ZnO:Al/Ni heterojunction device

Both bipolar and unipolar resistive switching (RS) characteristics have been demonstrated based on p+-Si/ZnO:Al/Ni heterojunction device. Here, the Al nanoparticles are introduced at the p+-Si/n-ZnO interface by sputtering deposition and thermal annealing. The p+-Si/ZnO:Al/Ni device, especially for the negative RS process, shows smaller resistive voltages and more concentrated resistance distributions than the device without Al nanoparticles. For the device with Al nanoparticles, the Al nanoparticles can eliminate the potential barrier of p+-Si/n-ZnO interface and act as tip electrodes for RS, while the location without Al nanoparticles at the interface is not easy to form the conducting filaments (CFs) due to the existence of interface potential barrier. The electric field can be enhanced and concentrated and lead to a simplified-CFs structure along the Al nanoparticles. Thus, p+-Si/ZnO:Al/Ni heterojunction device can effectively improve the RS uniformity.