Impact of morphology on charge carrier mobility in top gate C60 organic field effect transistors

Akash Nigam, Gunther Schwabegger, Rizwan Ahmed, Clemens Simbrunner, Helmut Sitter, Malin Premaratne, Ramgopal V. Rao

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Charge carrier mobility is a critical parameter in organic field effect transistors and it is strongly influenced by morphology and structure of the involved organic materials. In this work, we present a study on impact of grain size and surface roughness of the active layer on the mobility in top gate n-type C60 organic field effect transistors. The morphology was varied by changing the substrate temperature during C60 deposition from 100 °C to 200 °C. It is found that for the investigated top gate devices, the mobility does not strictly increase with increasing grain size, which is in disagreement with the trends reported for bottom gate OFETs. The observation is explained by the fact that the increasing grain size of C60 leads to a concurrent increase in the surface roughness, which negatively impacts the charge carrier mobility in the active channel of the OFET. As a result an optimum of the mobility is reached at 150 °C of substrate temperature where grains are already quite big, but surface roughness is still not hindering the transport.

Original languageEnglish
Title of host publication2014 IEEE 2nd International Conference on Emerging Electronics (ICEE 2014)
Subtitle of host publicationBengaluru, India, 3-6 December, 2014 [Proceedings]
PublisherIEEE, Institute of Electrical and Electronics Engineers
Number of pages3
ISBN (Electronic)9781467365284
ISBN (Print)9781467365277, 9781467365291
Publication statusPublished - Jul 2015
EventIEEE International Conference on Emerging Electronics 2014 - Bengaluru, India
Duration: 3 Dec 20146 Dec 2014
Conference number: 2nd


ConferenceIEEE International Conference on Emerging Electronics 2014
Abbreviated titleICEE 2014

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