Unipolar resistive switching properties of Pr-doped ZnO thin films

Pr-doped ZnO hexagonal structure thin films with c-axis preferred orientation were deposited on Pt/Ti/SiO2/Si substrates by chemical solution deposition technique. The effects of Pr doping amount on the resistive switching behavior of Pt/Zn1−xPrxO/Pt (x = 0, 0.01, 0.03, and 0.05) memory cells were investigated. The results showed that Pr-doping lowered the c-axis orientation degree of the ZnO thin films, but improved the resistive switching properties of Pt/Zn1−xPrxO/Pt devices. The resistive switching devices exhibited good endurance, long retention, and uniform switching voltages. I-V characteristics and their temperature dependence analysis indicated that the conduction mechanism of LRS was Ohmic behavior, and that of HRS at relatively higher voltage is trap-controlled space charge limited current. The physical origin of the resistive switching can be referred to the formation and rupture of the oxygen vacancies related filaments.