Ultraviolet photodetecting and plasmon-to-electric conversion of controlled inkjet-printing thin-film transistors

Cheng Jyun Wang, Hsin Chiang You, Jen Hung Ou, Yun Yi Chu, Fu-Hsiang Ko*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Direct ink-jet printing of a zinc-oxide-based thin-film transistor (ZnO-based TFT) with a three-dimensional (3-D) channel structure was demonstrated for ultraviolet light (UV) and visible light photodetection. Here, we demonstrated the channel structures by which temperature-induced Marangoni flow can be used to narrow the channel width from 318.9 ± 44.1 µm to 180.1 ± 13.9 µm via a temperature gradient. Furthermore, a simple and efficient oxygen plasma treatment was used to enhance the electrical characteristics of switching ION/IOFF ratio of approximately 105. Therefore, the stable and excellent gate bias-controlled photo-transistors were fabricated and characterized in detail for ultraviolet (UV) and visible light sensing. The photodetector exhibited a superior photoresponse with a significant increase of more than 2 orders of magnitude larger drain current generated upon UV illumination. The results could be useful for the development of UV photodetectors by the direct-patterning ink-jet printing technique. Additionally, we also have successfully demonstrated that a metal-semiconductor junction structure that enables plasmon energy detection by using the plasmonic effects is an efficient conversion of plasmon energy to an electrical signal. The device showed a significant variations negative shift of threshold voltage under different light power density with exposure of visible light. With the ZnO-based TFTs, only ultraviolet light detection extends to the visible light wavelength.

Original languageEnglish
Article number458
Pages (from-to)1-15
Number of pages15
Issue number3
StatePublished - 4 Mar 2020


  • Ink-jet printing
  • Oxygen plasma treatment
  • Plasmon energy detection
  • Visible light photodetection
  • Zinc-oxide-based thin-film transistors


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