Thermionic Emission and Tunneling at Carbon Nanotube-Organic Semiconductor Interface

    Authors

    B. K. Sarker;S. I. Khondaker

    Comments

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    Abbreviated Journal Title

    ACS Nano

    Keywords

    carbon nanotube electrodes; organic semiconductor; charge injection; barrier height; thermionic emission; Fowler-Nordheim tunneling; direct; tunneling; FIELD-EFFECT TRANSISTORS; ENERGY-LEVEL ALIGNMENT; THIN-FILM TRANSISTORS; CHARGE INJECTION; ELECTRODES; METAL; POLYMER; NANOWIRES; MOLECULES; DEVICES; Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience &; Nanotechnology; Materials Science, Multidisciplinary

    Abstract

    We study the charge carrier injection mechanism across the carbon nanotube (CNT)-organic semiconductor interface using a densely aligned carbon nanotube array as electrode and pentacene as organic semiconductor. The current density-voltage (J-V) characteristics measured at different temperatures show a transition from a thermal emission mechanism at high temperature (above 200 K) to a tunneling mechanism at low temperature (below 200 K). A barrier height of similar to 0.16 eV is calculated from the thermal emission regime, which is much lower compared to the metal/pentacene devices. At low temperatures, the J-V curves exhibit a direct tunneling mechanism at low bias, corresponding to a trapezoidal barrier, while at high bias the mechanism is well described by Fowler-Nordheim tunneling, which corresponds to a triangular barrier. A transition from direct tunneling to Fowler-Nordheim tunneling further signifies a small injection barrier at the CNT/pentacene interface. Our results presented here are the first direct experimental evidence of low charge carrier injection barrier between CNT electrodes and an organic semiconductor and are a significant step forward in realizing the overall goal of using CNT electrodes in organic electronics.

    Journal Title

    Acs Nano

    Volume

    6

    Issue/Number

    6

    Publication Date

    1-1-2012

    Document Type

    Article

    Language

    English

    First Page

    4993

    Last Page

    4999

    WOS Identifier

    WOS:000305661300047

    ISSN

    1936-0851

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