Modulation of memory effect in organic phototransistors by controlling energy barrier between organic semiconductor and source electrode

Hea Lim Park, Min Hoi Kim, Hyeok Kim

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

The interfacial characteristics both at the organic semiconductor (OSC)/gate insulator and OSC/source (S) and drain (D) are considered important factors affecting the charge carrier in organic electronics, but their effects on the optoelectrical performance of organic phototransistors (OPTs) have not been adequately studied. In this study, the effect of the energy barrier at the OSC/S interface on the photoresponse of an OPT is investigated and found to be significant. It is seen that the photoresponsive dynamics of the OPT are governed by the interplay between the energy barrier and the occupied trap sites. In a device with a relatively low energy barrier (Au-based OPT), the optical memory effect (slow decay time) is exhibited with high sensitivity to the trapping of photo-generated electrons, whereas, for the Al-based device with a high energy barrier, photo-sensing characteristics occur because of the low sensitivity toward the trapped electrons after light exposure. Our prototype OPT employing asymmetric SD electrodes exhibits the dual functions of optical memory and switching devices in a single cell. Each function of the device is selectively activated by the bias condition.

Original languageEnglish
Article number025011
JournalSemiconductor Science and Technology
Volume35
Issue number2
DOIs
StatePublished - 2020

Keywords

  • energy barrier
  • memory effect
  • organic phototransistor
  • trapping

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