Fatigue mechanism verified using photovoltaic properties of Pb(Zr_0.52Ti_0.48)O₃ thin films

The photovoltaic effect and its evolution during electrical fatigue in Pb(Zr_0.52Ti_0.48)O₃ (PZT) thin films have been investigated. It is found that the photovoltaic effect of the as-grown PZT thin film is highly affected by the asymmetric Schottky barriers, which can be tuned by applying an external electric field. During fatigue processes, both open-circuit voltage (V_oc) and short-circuit current (J_sc) decrease considerably with the increase of the number of electrical cycles. This phenomenon could be ascribed to the degradation of the interfacial layer between the thin film and the electrode induced by highly energetic charge carriers injected from the electrode during bipolar cycling. Our work sheds light on the physical mechanism of both ferroelectric photovoltaics and polarization fatigue in thin-film ferroelectrics.