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Gated three-terminal device architecture to eliminate persistent photoconductivity in oxide semiconductor photosensor arrays

A Corrigendum to this article was published on 24 March 2015

This article has been updated


The composition of amorphous oxide semiconductors, which are well known for their optical transparency1,2,3,4, can be tailored to enhance their absorption and induce photoconductivity for irradiation with green, and shorter wavelength light. In principle, amorphous oxide semiconductor-based thin-film photoconductors could hence be applied as photosensors. However, their photoconductivity persists for hours after illumination has been removed5,6, which severely degrades the response time and the frame rate of oxide-based sensor arrays. We have solved the problem of persistent photoconductivity (PPC) by developing a gated amorphous oxide semiconductor photo thin-film transistor (photo-TFT) that can provide direct control over the position of the Fermi level in the active layer. Applying a short-duration (10 ns) voltage pulse to these devices induces electron accumulation and accelerates their recombination with ionized oxygen vacancy sites, which are thought to cause PPC. We have integrated these photo-TFTs in a transparent active-matrix photosensor array that can be operated at high frame rates and that has potential applications in contact-free interactive displays.

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Figure 1: The structure of an amorphous oxide semiconductor photosensor pixel comprising a gated three-terminal photosensor and a gated three-terminal switch.
Figure 2: Electrical, material and optical characteristics of IZO, GIZO, and GIZO/IZO/GIZO devices.
Figure 3: PPC phenomenon of an oxide-based sensor device.
Figure 4: Fermi-level control of oxide–semiconductor to eliminate the PPC phenomenon, and demonstration of a photosensor screen.

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  • 16 February 2015

    In the version of this Letter originally published, Khashayar Ghaffarzadeh, with affiliation at the London Centre for Nanotechnology, University College London, London WC1H 0AH, UK, had been omitted from the list of authors. Following internal and external investigations, this has now been corrected in the online versions of the Letter. Sanghun Jeon, Seung-Eon Ahn, Ihun Song, Chang Jung Kim, U-In Chung, Inkyung Yoo and Kinam Kim disagree with this correction.


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The authors are grateful to SAIT colleagues Y. K. Cha, K. J. Park and C. Y. Moon for assistance with the experiments, and S. Heo and J. Lee for X-ray photoelectron spectroscopy analysis.

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Authors and Affiliations



S.J., S-E.A. and I.S. designed this work. S.J. and A.N. prepared the manuscript. S.J., S-E.A. and I.S. carried out the experiment and electrical analysis. E-h.L. performed transmission electron microscopy analysis. S.L. worked on drawing the energy band diagram and deriving the equations. A.N. and J.R. contributed to analysis and interpretation of results relevant to persistent photoconductivity and photoconductive gain. All authors discussed the results and implications and commented on the manuscript at all stages.

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Correspondence to Sanghun Jeon or Ihun Song.

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Jeon, S., Ahn, SE., Song, I. et al. Gated three-terminal device architecture to eliminate persistent photoconductivity in oxide semiconductor photosensor arrays. Nature Mater 11, 301–305 (2012).

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