Leakage current and relaxation characteristics of highly (111)-oriented lead calcium titanate thin films

Abstract

Highly (111)-oriented (Pb0.76Ca0.24)TiO3 (PCT) thin films were grown on Pt/Ti/SiO2/Si substrates by a sol–gel process. The Au/PCT/Pt metal–insulator–metal film capacitor showed well-saturated hysteresis loops at an applied field of 800 kV/cm with remanent polarization (Pr) and coercive electric field (Ec) values of 18.2 μC/cm2 and 210 kV/cm, respectively. The leakage current depended on the voltage polarity. At low electrical field and with Pt electrode biased negatively, the Pt/PCT interface exhibits a Schottky emission characteristics. The Au/PCT interface forms an ohmic contact. The conduction current when the Au electrode is biased negatively shows a space-charge-limited behavior. The dielectric relaxation current behavior of Au/PCT/Pt capacitor obeys the well-known Curie–von Schweidler law at low electric field. At higher fields, the currents have contributions to both dielectric relaxation current and leakage current.

Influence of SrTiO3 Buffer Layer on the Ferroelectric Properties of Bi2NiMnO6 Thin Film

“…When the voltage was applied at BNMO/STO thin film, the leakage current density increased with the applied field, then reached to 0.187 A/ cm 2 . The negative leakage current was limited by the interface between the Pt bottom electrode and the thin films (the bottom interface), while the positive leakage current was limited by the interface between the Au top electrode and the thin films (the top interface) indicating an ohmic mechanism [13]. Downloaded by [East Carolina University] at 19:07 04 January 2013 …”

Charge Transport in Ferroelectric Thin Films

“…-Different metals are used for electrodes, neglecting the fact that the metal-ferroelectric interface is part of the ferroelectric capacitor on which the I-V measurement is performed. The fit of the experimental data with one or another of the conduction mechanisms is performed without investigating the interface properties and behavior, whatever the metal contact is ohmic or rectifying (Tang et al, 2003;Nunez & Nardelli, 2008). …”

Improved electric property in SrTiO3–Bi2NiMnO6–SrTiO3 sandwich structural thin films

“…The leakage current was little lower for Pt electrode under a positive bias voltage than negative bias voltage. In fact, the leakage current in two opposite directions was limited by the interface between thin film and the Pt or Au electrodes, respectively [23]. As can be seen, the leakage current density of BNM film is very large, which is corresponded with the result from the ferroelectric analysis.…”

“…Due to carrier injection, the density of free electrons becomes greater than the density of thermally stimulated free electrons at a sufficiently high applied electric field region. Then the current density follows the space charge limited conduction (SCLC) mechanism [23]. The current density for SCLC can be described by equation below [27]:…”