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Understanding charge transport in lead iodide perovskite thin-film field-effect transistors

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Science Advances  27 Jan 2017:
Vol. 3, no. 1, e1601935
DOI: 10.1126/sciadv.1601935
  • Fig. 1 Effect of grain size on the characteristics of FET devices with gold S-D contacts.

    (A) Scanning electron microscopy (SEM) images of MAPbI3 films fabricated from 0.25, 0.5, and 0.75 M precursor solutions. Scale bars, 200 nm. (B) Grain size as a function of concentration of the precursor solution. (C) Transfer characteristics at 100 and 270 K for MAPbI3 FETs with channel length (L) = 10 μm and width (W) = 1 mm deposited with different precursor concentrations. (D) μFET as a function of precursor concentration measured from perovskite FETs at 100 and 270 K.

  • Fig. 2 Electrical characterization of MAPbI3 FETs with different S-D contact modifications.

    Transfer characteristics at (A) 100 K for different S-D contact modification and (B) 300 K for PEIE-treated Au contacts. Also shown is the square root of Ids and the linear fit over a large positive Vg range. Output characteristics of FETs with PEIE-treated Au S-D contacts at (C) 100 K and (D) 300 K (L = 20 μm and W = 1 mm). (E) Transfer characteristics measured at 100 K upon thermal cycling. (F) Effect of the base voltage variation on the transconductance plots for the same FET. The inset shows a schematic diagram of the pulse voltage. For all devices, we used a 0.75 M precursor concentration.

  • Fig. 3 Temperature-dependent transport measurements on MAPbI3 FETs.

    (A) μFET(T) with different interlayers at the S-D contacts depicting three different regimes of charge transport with a power law behavior: μ ~ μ0T−γ. Region I: inorganic cage vibrational disorder (γ ~0.2 to 0.4); region II: dominated by the polarization fluctuation of MA+; region III: dominated by ion migration (γ ~4.1 to 5.3). (B) μFET(T) from FETs fabricated with different precursor concentration of perovskite solutions and PEIE-modified S-D electrodes. (C) Schematic of top-gate bottom-contact perovskite FETs summarizing the different sources of disorder mechanisms prevalent in a perovskite FETs corresponding to different regimes in the μFET(T) (left: vibrations of inorganic cage; middle: defect migration; right: MA+ polarization disorder).

  • Fig. 4 Spectroscopic investigation of the sources of disorder in MAPbI3 thin films.

    (A) Capacitance of 250-nm-thick perovskite thin films measured on an Au/perovskite/Au sandwich device (schematically shown in the inset) as a function of temperature in steps of 40 K with an applied ac voltage of 30 mV. (B) Corresponding dielectric loss measurement as a function of frequency and temperature. (C) Raman spectra for 0.75 and 0.25 M perovskite thin films as well as reference single crystals measured at room temperature with a 532-nm laser excitation. The inset shows the Lorentzian fits to the different peaks of the spectrum. a.u., arbitrary units. (D) Plot of the shift in peak position corresponding to the vibration mode of MA+ and the Pb-I octahedron with temperature. The insets show a schematic representation of the corresponding molecular vibrations.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/1/e1601935/DC1

    section S1. Characterization of the perovskite films

    section S2. PbI2 precursor–based perovskite FETs

    section S3. Output characteristics of perovskite FETs

    section S4. Mobility extraction for temperature-dependent transport measurements

    section S5. Hysteresis in perovskite FETs

    section S6. Detailed characteristics of Au-PFBT–based perovskite FETs

    section S7. Role of interlayers at the S-D electrodes

    section S8. Bias stress measurements on perovskite FETs

    section S9. Transfer characteristics in continuous mode bias

    section S10. Ferroelectric polarization measurement

    section S11. Dielectric dependence of the hysteresis in transfer curves

    section S12. Role of thermal cycling on the charge transport

    section S13. Regimes of transport in μFET(T)

    section S14. Impedance spectroscopy

    section S15. Estimation of Urbach energy (Eu) with temperature

    section S16. Temperature-dependent Raman measurement

    section S17. Temperature-dependent absorption measurement

    fig. S1. Microscopic characterization.

    fig. S2. XRD measured on different perovskite thin films.

    fig. S3. High-resolution XRD indicating the assigned peaks for 0.25 M perovskite films.

    fig. S4. Structural characterization.

    fig. S5. PbI2 precursor–based transistors.

    fig. S6. Effect of grain size on FET characteristics.

    fig. S7. Typical mobility extraction from linear fits to the Formula with Vg for Vd = 60 V.

    fig. S8. Histograms of mobilities extracted from perovskite FETs fabricated from 0.75 M solution and PEIE-treated electrodes.

    fig. S9. Hysteresis in output characteristics.

    fig. S10. Close to room temperature characterization of dual-gated FETs.

    fig. S11. Low-temperature characterization of dual-gated FETs.

    fig. S12. Au-PFBT–treated FET characterization.

    fig. S13. Characterization of interlayer treatment on electrodes.

    fig. S14. SEM images of the perovskite thin films in different regions around the lithographically patterned pristine Au and modified Au S-D electrodes used for the FET fabrication.

    fig. S15. SEM image of 0.5 M perovskite films depicting the difference in nucleation and grain size in the channel and on top of the electrodes near the channel-electrode interface for bare Au (left) and PEIE-treated S-D contacts.

    fig. S16. XRD pattern obtained from the perovskite films (0.75 M precursor) fabricated on different substrates.

    fig. S17. Stability towards bias stress.

    fig. S18. Bias stress measurement of the output characteristics at different temperatures measured on perovskite FETs fabricated from 0.75 M precursor solution and Au S-D electrodes.

    fig. S19. Bias stress measurement of the output characteristics at different temperatures measured on perovskite FETs fabricated from 0.75 M precursor solution and PEIE-treated Au S-D electrodes.

    fig. S20. Temperature-dependent transfer characteristics measured at Vd = 60 V for perovskite FETs fabricated with 0.75 M precursor, Au-PEIE S-D electrode, and Cytop dielectric measured under a continuous mode of bias.

    fig. S21. Representative polarization (P)–electric field (E) loops measured on an Au/perovskite (~0.7 μm)/Au sandwich device at different temperatures and frequency.

    fig. S22. Normalized transfer curves for perovskite FET devices fabricated with 0.75 M Au-PEIE device with Cytop and PMMA dielectric layer.

    fig. S23. Effect of Vd on FET hysteresis.

    fig. S24. Effect of temperature cycling on the performance of a perovskite transistor fabricated with 0.75 M precursor solution, Cytop dielectric layer, and PFBT-treated Au S-D electrodes.

    fig. S25. Transfer characteristics measured on perovskite devices (0.75 M; Au-PEIE–treated electrodes), indicating the effect of biasing at Vg = Vd = 60 V on the FET performance during the first cycle of transistor performance.

    fig. S26. Transfer characteristics measured on perovskite devices (0.75 M; Au-PEIE–treated electrodes) upon thermal cycling.

    fig. S27. Transfer characteristics measured on perovskite devices (0.75 M; Au-PEIE–treated electrodes) while biasing during thermal cycling.

    fig. S28. Effect of thermal cycling and bias on the capacitance of perovskite films measured at different temperature.

    fig. S29. Effect of thermal cycling on energetic disorder in perovskite thin films.

    fig. S30. Structural characterization of the perovskite thin films of different precursor concentrations upon thermal cycling.

    fig. S31. Effect of thermal cycling on the perovskite grain size.

    fig. S32. Transfer curves measured at 100 K from a FET fabricated with a 0.75 M Au-PEIE–treated S-D electrodes with Cytop dielectric layer depicting the effect of thermal cycling.

    fig. S33. μFET(T) for perovskite transistors fabricated from perovskite films with different precursor concentration.

    fig. S34. Temperature dependence impedance measurement.

    fig. S35. Temperature-dependent disorder estimation in perovskite thin films.

    fig. S36. Raman spectra measured on thin films fabricated with different grain size.

    fig. S37. Temperature-dependent absorption measurements showing evidence of the phase transition from tetragonal to orthorhombic phase over the temperature range of 160 to 170 K for perovskite films of different grain sizes.

  • Supplementary Materials

    This PDF file includes:

    • section S1. Characterization of the perovskite films
    • section S2. PbI2 precursor–based perovskite FETs
    • section S3. Output characteristics of perovskite FETs
    • section S4. Mobility extraction for temperature-dependent transport measurements
    • section S5. Hysteresis in perovskite FETs
    • section S6. Detailed characteristics of Au-PFBT–based perovskite FETs
    • section S7. Role of interlayers at the S-D electrodes
    • section S8. Bias stress measurements on perovskite FETs
    • section S9. Transfer characteristics in continuous mode bias
    • section S10. Ferroelectric polarization measurement
    • section S11. Dielectric dependence of the hysteresis in transfer curves
    • section S12. Role of thermal cycling on the charge transport
    • section S13. Regimes of transport in μFET (T)
    • section S14. Impedance spectroscopy
    • section S15. Estimation of Urbach energy (Eu) with temperature
    • section S16. Temperature-dependent Raman measurement
    • section S17. Temperature-dependent absorption measurement
    • fig. S1. Microscopic characterization.
    • fig. S2. XRD measured on different perovskite thin films.
    • fig. S3. High-resolution XRD indicating the assigned peaks for 0.25 M perovskite films.
    • fig. S4. Structural characterization.
    • fig. S5. PbI2 precursor–based transistors.
    • fig. S6. Effect of grain size on FET characteristics.
    • fig. S7. Typical mobility extraction from linear fits to the I 0.5 ds with Vg for Vd = 60 V.
    • fig. S8. Histograms of mobilities extracted from perovskite FETs fabricated from 0.75 M solution and PEIE-treated electrodes.
    • fig. S9. Hysteresis in output characteristics.
    • fig. S10. Close to room temperature characterization of dual-gated FETs.
    • fig. S11. Low-temperature characterization of dual-gated FETs.
    • fig. S12. Au-PFBT–treated FET characterization.
    • fig. S13. Characterization of interlayer treatment on electrodes.
    • fig. S14. SEM images of the perovskite thin films in different regions around the lithographically patterned pristine Au and modified Au S-D electrodes used for the FET fabrication.
    • fig. S15. SEM image of 0.5 M perovskite films depicting the difference in nucleation and grain size in the channel and on top of the electrodes near the channel-electrode interface for bare Au (left) and PEIE-treated S-D contacts.
    • fig. S16. XRD pattern obtained from the perovskite films (0.75 M precursor) fabricated on different substrates.
    • fig. S17. Stability towards bias stress.
    • fig. S18. Bias stress measurement of the output characteristics at different temperatures measured on perovskite FETs fabricated from 0.75 M precursor solution and Au S-D electrodes.
    • fig. S19. Bias stress measurement of the output characteristics at different temperatures measured on perovskite FETs fabricated from 0.75 M precursor solution and PEIE-treated Au S-D electrodes.
    • fig. S20. Temperature-dependent transfer characteristics measured at Vd = 60 V for perovskite FETs fabricated with 0.75 M precursor, Au-PEIE S-D electrode, and Cytop dielectric measured under a continuous mode of bias.
    • fig. S21. Representative polarization (P)–electric field (E) loops measured on an Au/perovskite (~0.7 μm)/Au sandwich device at different temperatures and frequency.
    • fig. S22. Normalized transfer curves for perovskite FET devices fabricated with 0.75 M Au-PEIE device with Cytop and PMMA dielectric layer.
    • fig. S23. Effect of Vd on FET hysteresis.
    • fig. S24. Effect of temperature cycling on the performance of a perovskite transistor fabricated with 0.75 M precursor solution, Cytop dielectric layer, and PFBT-treated Au S-D electrodes.
    • fig. S25. Transfer characteristics measured on perovskite devices (0.75 M;
      Au-PEIE–treated electrodes), indicating the effect of biasing at Vg = Vd = 60 V on the FET performance during the first cycle of transistor performance.
    • fig. S26. Transfer characteristics measured on perovskite devices (0.75 M; Au-PEIE–treated electrodes) upon thermal cycling.
    • fig. S27. Transfer characteristics measured on perovskite devices (0.75 M; Au-PEIE–treated electrodes) while biasing during thermal cycling.
    • fig. S28. Effect of thermal cycling and bias on the capacitance of perovskite films measured at different temperature.
    • fig. S29. Effect of thermal cycling on energetic disorder in perovskite thin films.
    • fig. S30. Structural characterization of the perovskite thin films of different precursor concentrations upon thermal cycling.
    • fig. S31. Effect of thermal cycling on the perovskite grain size.
    • fig. S32. Transfer curves measured at 100 K from a FET fabricated with a 0.75 M Au-PEIE–treated S-D electrodes with Cytop dielectric layer depicting the effect of thermal cycling.
    • fig. S33. μFET(T) for perovskite transistors fabricated from perovskite films with different precursor concentration.
    • fig. S34. Temperature dependence impedance measurement.
    • fig. S35. Temperature-dependent disorder estimation in perovskite thin films.
    • fig. S36. Raman spectra measured on thin films fabricated with different grain size.
    • fig. S37. Temperature-dependent absorption measurements showing evidence of the phase transition from tetragonal to orthorhombic phase over the temperature range of 160 to 170 K for perovskite films of different grain sizes.

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