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Fast, sensitive and spectrally tuneable colloidal-quantum-dot photodetectors

Abstract

Solution-processed semiconductors are compatible with a range of substrates, which enables their direct integration with organic circuits1,2, microfluidics3,4, optical circuitry1,5 and commercial microelectronics. Ultrasensitive photodetectors based on solution-process colloidal quantum dots operating in both the visible and infrared have been demonstrated6,7, but these devices have poor response times (on the scale of seconds) to changes in illumination, and rapid-response devices based on a photodiode architecture suffer from low sensitivity8. Here, we show that the temporal response of these devices is determined by two components—electron drift, which is a fast process, and electron diffusion, which is a slow process. By building devices that exclude the diffusion component, we are able to demonstrate a >1,000-fold improvement in the sensitivity–bandwidth product of tuneable colloidal-quantum-dot photodiodes operating in the visible and infrared6,7,8.

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Figure 1: Photodiode structure, energy bands and photocurrent components.
Figure 2: Photodiode spectral response, illumination response and frequency response.
Figure 3: Photodiode transient response and quantum efficiency as a function of bias and irradiance.
Figure 4: Fully depleted photodiode spectral response and frequency response.

References

  1. Xue, J. & Forrest, S. R. Organic optical bistable switch. Appl. Phys. Lett. 82, 136–138 (2003).

    Article  Google Scholar 

  2. Kymissis, I., Sodini, C. G., Akinwande, A. I. & Bulovic, V. An organic semiconductor based process for photodetecting applications. 2004 IEDM Tech. Dig., 377–380 (2004).

  3. Hofmann, O. et al. Thin-film organic photodiodes as integrated detectors for microscale chemiluminescence assays. Sens. Actuators B 106, 878–884 (2005).

    Article  Google Scholar 

  4. Wang, X. Integrated thin-film polymer/fullerene photodetectors for on-chip microfluidic chemiluminescence detection. Lab. Chip 7, 58–63 (2007).

    Article  Google Scholar 

  5. Morimune, T., Kajii, H. & Ohmori, Y. Semitransparent organic photodetectors utilizing sputter-deposited indium tin oxide for top contact electrode. Jpn J. Appl. Phys. 44, 2815–2817 (2005).

    Article  Google Scholar 

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

    Article  Google Scholar 

  7. Konstantatos, G., Clifford, J. P., Levina, L. & Sargent, E. H. Sensitive solution-processed visible-wavelength photodetectors. Nature Photon. 1, 531–534 (2007).

    Article  Google Scholar 

  8. Oertel, D. C., Bawendi, M. G., Arango, A. C. & Bulovic, V. Photodetectors based on treated CdSe quantum-dot films. Appl. Phys. Lett. 87, 2135051 (2005).

    Article  Google Scholar 

  9. Wise, F. W. Lead salt quantum dots: the limit of strong quantum confinement. Acc. Chem. Res. 33, 773–780 (2000).

    Article  Google Scholar 

  10. Jones, A. V. The infrared spectrum of the airglow. Space Science Rev. 15, 355–400 (1973).

    Article  Google Scholar 

  11. Sargent, E. H. Infrared quantum dots. Adv. Mater. 17, 515–522 (2005).

    Article  Google Scholar 

  12. Kim, S. et al. Near-infrared fluorescent type II quantum dots for sentinel lymph node mapping. Nature Biotechnol. 22, 93–97 (2004).

    Article  Google Scholar 

  13. Jarosz, M. V., Porter, V. J., Fisher, B. R., Kastner, M. A. & Bawendi, M. G. Photoconductivity studies of treated CdSe quantum dot films exhibiting increased exciton ionization efficiency. Phys. Rev. B 70, 195327 (2004).

  14. Luther, J. M. et al. Structural, optical and electrical properties of self-assembled films of PbSe nanocrystals treated with 1,2-ethanedithiol. ACS Nano 2, 271–280 (2008).

    Article  Google Scholar 

  15. Talapin, D. V. & Murray, C. B. PbSe nanocrystal solids for n- and p-channel thin film field-effect transistors. Science 310, 86–89 (2005).

    Article  Google Scholar 

  16. Clifford, J. P., Johnston, K. W., Levina, L. & Sargent, E. H. Schottky barriers to colloidal quantum dot films. Appl. Phys. Lett. 91, 2531171 (2007).

    Article  Google Scholar 

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Acknowledgements

The authors thank D. Grozea for performing the XPS measurements.

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Authors and Affiliations

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Contributions

J.P.C conceived and fabricated the CQD photodiodes, performed all device performance characterization, and conceived and implemented the CQD photodiode device model. G.K. coordinated and interpreted the XPS measurements. K.W.J. and J.P.C co-developed the first step of the CQD surface modification strategy. S.H. and J.P.C. co-developed the second step of the CQD surface modification strategy. L.L. synthesized all CQDs used to fabricate the devices. E.H.S. assisted in interpretation of the results, commented on the device model, and commented on the manuscript. All authors discussed the results and the capacity of the model to describe the underlying physics of device operation.

Corresponding author

Correspondence to Edward H. Sargent.

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Clifford, J., Konstantatos, G., Johnston, K. et al. Fast, sensitive and spectrally tuneable colloidal-quantum-dot photodetectors. Nature Nanotech 4, 40–44 (2009). https://doi.org/10.1038/nnano.2008.313

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