Tuesday, April 30, 2013

1304.7514 (Loïk Gence et al.)

Nonlinear switching in asymmetric hybrid metal- polymer nanowires    [PDF]

Loïk Gence, Vincent Callegari, Sophie Demoustier-Champagne, Jean-Luc Duvail
In this paper, we report on the impact of metal/polymer interfaces on the rectifying behavior of hybrid nanowires (HNWs) made of metallic and conjugated polymer (CP) segments. Using micromachined devices the electronic properties and HNW structure relationship are revealed. By combining transmission electron microscopy and current-voltage (I-V) spectroscopy performed on several symmetric and asymmetric HNW structures, we show that rectifying I-V characteristics are observed only for asymmetric HNWs. Interestingly, the experimental results demonstrate that the rectification ratio can be improved up to 3 orders of magnitude by a proper selection of the HNW composition. While the rectifying behavior is observed in HNWs after oxidative or acid doping, the charge transport mechanism in as-synthesized HNWs is bulk-limited and independent from their structure. Both symmetric and asymmetric HNWs exhibit Ohmic and non- linear I-V curves above and below T=120 K, respectively. Our data is consistent with a smooth transition from an Ohmic to non-Ohmic variable-range-hopping (VRH) mechanism. We discuss the origin of these nonlinearities comparing the two- and four-probe measurements of single HNWs and propose a simple model based on dual back-to- back Schottky diodes to explain qualitatively the rectifying properties.
View original: http://arxiv.org/abs/1304.7514

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