Carrier density-dependent transport in poly(3-methylthiophene): from injection-limited to space-charge-limited current

Anjaneyulu, P and Sangeeth, Suchand CS and Menon, Reghu (2011) Carrier density-dependent transport in poly(3-methylthiophene): from injection-limited to space-charge-limited current. In: Journal of Physics D: Applied Physics, 44 (31).

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Abstract

Current-voltage (I-V) and impedance measurements were carried out in doped poly(3-methylthiophene) devices by varying the carrier density. As the carrier concentration reduces the I-V characteristics indicate that the conduction mechanism is limited by metal-polymer interface, as also observed in impedance data. The temperature dependence of I-V in moderately doped samples shows a trap-controlled space-charge-limited conduction (SCLC); whereas in lightly doped devices injection-limited conduction is observed at lower bias and SCLC at higher voltages. The carrier density-dependent quasi-Fermi level adjustment and trap-limited transport could explain this variation in conduction mechanism. Capacitance measurements at lower frequencies and higher bias voltages show a sign change in values due to the significant variations in the relaxation behaviour for lightly and moderately doped samples. The electrical hysteresis increases as carrier density is reduced due to the time scales involved in the de-trapping of carriers.

Item Type:	Journal Article
Publication:	Journal of Physics D: Applied Physics
Publisher:	Institute of Physics
Additional Information:	Copyright of this article belongs to Institute of Physics.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	05 Aug 2011 08:37
Last Modified:	05 Aug 2011 08:37
URI:	http://eprints.iisc.ac.in/id/eprint/39725

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