A study of bulk current mechanism in P3HT-based thin film transistors and approach for current suppression

Chia Hao Chang, Chao-Hsin Chien*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

In this article, poly(3-hexylthiophene) (P3HT) based thin film transistors with Ti capped source and drain electrodes (S/D) was employed to have an insight into the mechanism of bulk current effect, which led to poor subthreshold swing and large off current. Our newly developed PTFTs do show greater characteristics in the aspects of on/off current ratio and subthreshold swing than those with the conventional Au/Ti S/D. In order to explain the results, we propose that the bulk current is composed of two components, i.e., side-wall and top-face injections. We ascribe the improvements to the reduction of top-face injection bulk current due to the larger injection barrier between the P3HT and Ti. As comparing the PTFTs with Ti capped laterally grown multi-wall carbon nanotube (MWCNT) S/D with the PTFTs with MWCNT S/D, we also observe similar tendency of bulk current reduction. From the viewpoint of device operation, better subthreshold swing and smaller off current result in faster device switching and lower power consumption. By this new approach of S/D structure, there are two and 20 times improvements on the subthreshold swing and off current, respectively, although the reduction of the bulk current also leads to a slight decrease of the on-current.

Original languageEnglish
Pages (from-to)2620-2626
Number of pages7
JournalOrganic Electronics
Volume13
Issue number11
DOIs
StatePublished - 1 Jan 2012

Keywords

  • Bulk current effect
  • Electrodes
  • MWCNTs
  • OTFTs
  • P3HT
  • Polymer semiconductor

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