Publication Type:Journal Article
Source:Nanotechnology, Volume 22, Number 25 (2011)
Keywords:Applied bias, Barrier heights, Candidate mechanisms, Current voltage characteristics, Differential analysis, Electron transport, Electronic transport, Epitaxial films, Ferroelectric films, Ferroelectric thin films, ferroelectricity, Fowler-Nordheim tunneling, Hopping conduction, I - V curve, lead, Lead zirconate titanate, Phenomenological analysis, scanning probe microscopy, Semiconducting lead compounds, Spatial variations, Spatially resolved, zirconium
Differential analysis of current-voltage characteristics, obtained on the surface of epitaxial films of ferroelectric lead zirconate titanate (Pb(Zr 0.2Ti0.8)O3) using scanning probe microscopy, was combined with spatially resolved mapping of variations in local conductance to differentiate between candidate mechanisms of local electronic transport and the origin of disorder. Within the assumed approximations, electron transport was inferred to be determined by two mechanisms depending on the magnitude of applied bias, with the low-bias range dominated by the trap-assisted Fowler-Nordheim tunneling through the interface and the high-bias range limited by the hopping conduction through the bulk. Phenomenological analysis of the I-V curves has further revealed that the transition between the low-and high-bias regimes is manifested both in the strength of variations within the I-V curves sampled across the surface, as well as the spatial distribution of conductance. Spatial variations were concluded to originate primarily from the heterogeneity of the interfacial electronic barrier height with an additional small contribution from random changes in the tip-contact geometry. © 2011 IOP Publishing Ltd.
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