In the voltage range of 0–30 V, dielectric and leakage current density (JL) behavior were studied in paraelectric (Pb,La)Ti03 or PLT thin films (0.1–0.36 μ.m) with bulk resistivity of 5.6x108 Ω -cm. With Pt electrodes, the properties were found to be contact dominated. With both top and bottom Pt electrodes, the interfacial capacitance (Ci) and the built-in voltage (Vbi) of the Schottky barrier were 380 pF and 1.3 V, respectively. A log-log plot of vs V exhibit slope of -1 and 9, respectively, in the range of V<10 and 10<V<30. In the former voltage regime, the spatial dependence of the space charge density and therefore the electric field, makes analysis and interpretation of JL behavior nontrivial. Note that a slope of ∼1 may be misconstrued as ohmic behavior. In the 10<V<30 voltage regime, the Schottky emission expression was modified to account for the interfacial space charge layer widening with voltage. A linear In Jl vs V1/4 plot coupled with a Schottky barrier potential of 1.5 V, indicated that Schottky emission process was operational at the interface. Due to a similar voltage dependence, however, Poole-Frenkel emission cannot be ruled out.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Control and Systems Engineering
- Ceramics and Composites
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry