Visualization of trapped charges being ejected from organic thin-film transistor channels by Kelvin-probe force microscopy during gate voltage sweeps

Yuji Yamagishi, Kei Kobayashi, Kei Noda, Hirofumi Yamada

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Kelvin-probe force microscopy (KFM) has been widely used to evaluate the localized charge trap states in the organic thin-film transistor (OTFT) channels. However, applicability of the KFM has been limited to the trapped charges whose lifetime is typically longer than several minutes because of the temporal resolution of the KFM. Therefore, it has not long been employed for studying the dynamics of the trapped charges in the OTFTs. Here, we demonstrate a method to visualize the transient distribution of the trapped charge carriers in operating OTFTs. The method allows visualizing the dynamics of the trapped charges during the gate voltage sweeps on a time scale of several hundreds of milliseconds. The experimental results performed on dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) OTFTs indicate that, immediately after a bias voltage applied to a device was turned off, the primary discharging of the channel region around the electrode edges started and it limited the ejection process of the remaining accumulated charges to the electrodes, resulting in an increased density of long-lived trapped charges in a region distant from the electrodes. The presented results suggest that the method is useful to study the electrical connections at the interface between the DNTT grains and electrodes, or those between the grains.

Original languageEnglish
Article number093302
JournalApplied Physics Letters
Volume108
Issue number9
DOIs
Publication statusPublished - 2016 Feb 29

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transistors
microscopy
electrodes
probes
electric potential
thin films
thiophenes
temporal resolution
ejection
charge carriers
traps
life (durability)

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

Visualization of trapped charges being ejected from organic thin-film transistor channels by Kelvin-probe force microscopy during gate voltage sweeps. / Yamagishi, Yuji; Kobayashi, Kei; Noda, Kei; Yamada, Hirofumi.

In: Applied Physics Letters, Vol. 108, No. 9, 093302, 29.02.2016.

Research output: Contribution to journalArticle

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