Letter | Published:

A nanocomposite ultraviolet photodetector based on interfacial trap-controlled charge injection

Nature Nanotechnology volume 7, pages 798802 (2012) | Download Citation

Abstract

Ultraviolet photodetectors have applications in fields such as medicine, communications and defence1, and are typically made from single-crystalline silicon, silicon carbide or gallium nitride p–n junction photodiodes. However, such inorganic photodetectors are unsuitable for certain applications because of their high cost and low responsivity (<0.2 A W−1)2. Solution-processed photodetectors based on organic materials and/or nanomaterials could be significantly cheaper to manufacture, but their performance so far has been limited2,3,4,5,6,7. Here, we show that a solution-processed ultraviolet photodetector with a nanocomposite active layer composed of ZnO nanoparticles blended with semiconducting polymers can significantly outperform inorganic photodetectors. As a result of interfacial trap-controlled charge injection, the photodetector transitions from a photodiode with a rectifying Schottky contact in the dark, to a photoconductor with an ohmic contact under illumination, and therefore combines the low dark current of a photodiode and the high responsivity of a photoconductor (721–1,001 A W−1). Under a bias of <10 V, our device provides a detectivity of 3.4 × 1015 Jones at 360 nm at room temperature, which is two to three orders of magnitude higher than that of existing inorganic semiconductor ultraviolet photodetectors.

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References

  1. 1.

    & Solar-blind deep-UV band-pass filter (250–350 nm) consisting of a metal nano-grid fabricated by nanoimprint lithography. Opt. Express 18, 931–937 (2010).

  2. 2.

    , , , & Solution-processed ultraviolet photodetedtors based on colloidal ZnO nanoparticles. Nano Lett. 8, 1649–1653 (2008).

  3. 3.

    et al. Ultrasensitive solution-cast quantum dot photodetectors. Nature 442, 180–183 (2006).

  4. 4.

    , , , & Nanoparticle-assisted high photoconductive gain in composites of polymer and fullerene. Nature Nanotech. 3, 543–547 (2008).

  5. 5.

    , , & Colloidal quantum-dot photodetectors exploiting multiexciton generation. Science 324, 1542–1544 (2009).

  6. 6.

    & Nanostructured materials for photon detection. Nature Nanotech. 5, 391–400 (2010).

  7. 7.

    et al. High-detectivity polymer photodetectors with spectral response from 300 nm to 1450 nm. Science 325, 1665–1667 (2009).

  8. 8.

    et al. Broad spectral response using carbon nanotube/organic semiconductor/C60 photodetectors. Nano Lett. 9, 3354–3358 (2009).

  9. 9.

    Photonic Devices 960–986 (Cambridge Univ. Press, 2005).

  10. 10.

    & Optical constants of ZnO. Jpn. J. Appl. Phys. 36, 6237–6243 (1997).

  11. 11.

    Maximum performance of high-resistivity photoconductors. J. Appl. Phys. 29, 189–193 (1958).

  12. 12.

    , , & Optoelectronic characteristics of UV photodetector based on ZnO nanowire thin films. J. Alloy Comp. 479, 674–677 (2009).

  13. 13.

    , , , & High-performance UV detector made of ultra-long ZnO bridging nanowires. Nanotechnology 20, 045501 (2009).

  14. 14.

    , , , & Nanowire ultraviolet photodetectors and optical switches. Adv. Mater. 14, 158–160 (2002).

  15. 15.

    et al. ZnO nanowire UV photodetectors with high internal gain. Nano Lett. 7, 1003–1009 (2007).

  16. 16.

    et al. ZnO Schottky ultraviolet photodetectors. J. Cryst. Growth 225, 110–113 (2001).

  17. 17.

    et al. Giant enhancement in UV response of ZnO nanobelts by polymer surface-functionalization. J. Am. Chem. Soc. 129, 12096–12097 (2007).

  18. 18.

    et al. ZnO single nanowire-based UV detectors. Appl. Phys. Lett. 97, 022103 (2010).

  19. 19.

    , , , & Photoconductive UV detectors on sol–gel-synthesized ZnO films. J. Cryst. Growth 256, 73–77 (2003).

  20. 20.

    et al. The effect of three-dimensional morphology on the efficiency of hybrid polymer solar cells. Nature Mater. 8, 818–824 (2009).

  21. 21.

    , & Photovoltaic devices using blends of branched CdSe nanoparticles and conjugated polymers. Nano Lett. 3, 961–963 (2003).

  22. 22.

    , & Hybrid nanorod–polymer solar cells. Science 295, 2425–2427 (2002).

  23. 23.

    , & Electronic memory effects in diodes from a zinc oxide nanoparticle–polystyrene hybrid material. Appl. Phys. Lett. 89, 102103 (2006).

  24. 24.

    et al. Covalently bound hole-injecting nanostructures. Systematics of molecular architecture, thickness, saturation, and electron-blocking characteristics on organic light-emitting diode luminance, turn-on voltage, and quantum efficiency. J. Am. Chem. Soc. 127, 10227–10242 (2005).

  25. 25.

    , , , & Hybrid zinc oxide conjugated polymer bulk heterojunction solar cells. J. Phys. Chem. B 109, 9505–9516 (2005).

  26. 26.

    et al. Morphology evolution via self-organization and lateral and vertical diffusion in polymer: fullerene solar cell blends. Nature Mater. 7, 158–164 (2008).

  27. 27.

    , , , & Vertically segregated hybrid blends for photovoltaic devices with improved efficiency. J. Appl. Phys. 97, 014914 (2005).

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Acknowledgements

This work was supported by the Office of Naval Research (ONR, grant no. N000141210556), a Defense Threat Reduction Agency (DTRA) Young Investigator Award (HDTRA1-10-1-0098) and the University of Nebraska–Lincoln.

Author information

Affiliations

  1. Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA

    • Fawen Guo
    • , Bin Yang
    • , Yongbo Yuan
    • , Zhengguo Xiao
    • , Qingfeng Dong
    • , Yu Bi
    •  & Jinsong Huang

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Contributions

J.H. conceived the idea. J.H. and F.G. designed the experiments and analysed the data. F.G. carried out the fabrication of devices, measurements and data analysis. Y.B., B.Y. and Q.D. synthesized ZnO nanoparticles. B.Y. and Z.X. fabricated the single carrier devices. J.H. and F.G. wrote the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Jinsong Huang.

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DOI

https://doi.org/10.1038/nnano.2012.187

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