Research ArticleMATERIALS SCIENCE

Room temperature high-detectivity mid-infrared photodetectors based on black arsenic phosphorus

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Science Advances  30 Jun 2017:
Vol. 3, no. 6, e1700589
DOI: 10.1126/sciadv.1700589
  • Fig. 1 MIR photovoltaic detector based on b-AsP.

    (A) IR absorption spectra of the b-As0.83P0.17 sample. Inset: Schematic drawing of the b-As0.83P0.17 phototransistor for photodetection. (B) Ids-Vds characteristic curves with and without illumination, and photocurrent IP as a function of bias voltage at Vg = 0 V. The wavelength of the laser was 8.05 μm, and the power density was 0.17 W cm−2. Inset: Optical image of the device. Scale bar, 5 μm. (C) 2D counter plot of the MIR (4.034 μm) photocurrent as a function of Vds and Vg. The photocurrent generation mechanism is dominated by the PVE and PTE at zero-bias voltage. The incident laser power density was fixed at ~0.1 W cm−2. (D) Photocurrent versus gate voltage at various bias voltages. The sign of the photocurrent changes as the gate voltage increases at ~15 V from negative (p-doped) to positive (highly n-doped). (E) Schematic diagrams of energy structure diagrams at different doping types under a bias voltage Vds. Top panel: The sample of b-AsP working at the p-type region. Bottom panel: The device working at the n-type region. The black horizontal arrows indicate the direction of the photocurrent, which was caused by the PVE.

  • Fig. 2 Performance of the b-AsP photodetectors at MIR range at room temperature.

    (A) Photoresponsivity R (left) and EQE (right) of a typical device for wavelengths ranging from 2.4 to 8.05 μm. The measurements were performed at Vds = 0 V and Vg = 0 V. (B) Fast photoresponse of a typical device measured under a 4.034-μm laser (21.5 W cm−2) at Vds = 0 V and Vg = 0 V. Here, the rise/fall time was defined as the photocurrent increased/decreased from 10/90% to 90/10% of the stable photocurrent. (C) Measured photoresponsivity R (left axis) and EQE (right axis) of a typical device versus power of the incident laser (4.034 μm). The measurements were performed with Vds = 0 V and Vg = 0 V. (D) The Ids-Vds curves with and without illumination of the device. The x- and y-directions are labeled in the optical image in the inset. Scale bar, 5 μm. The wavelength of the incident laser was 4.034 μm, and the laser power was fixed at 21.5 Wcm−2.

  • Fig. 3 Rectifying curves and photoresponse of the b-AsP/MoS2 heterostructure detectors.

    (A) Ids-Vds characteristic curves (in logarithmic scale) with and without illumination (Vg = 0 V). The wavelength of the laser was 4.034 μm, and the power density was 1.09 W cm−2. Inset: Optical image of a typical b-AsP/MoS2 heterostructure device. Scale bar, 5 μm. (B) The current noise power spectra at Vds = 0 V of a b-AsP FET device (blue open circles) and a b-AsP/MoS2 heterostructure (red open squares). The black solid line (plotted as A/[1 + (f/f0)2]) is a reference for the 1/f noise trend. (C) Wavelength dependence of the noise equivalent power (NEP). (D) Wavelength dependence of the specific detectivity, D* (right axis), at Vds = 0 V. The purple and dark lines are commercial specific detectivity for a thermistor bolometer and PbSe MIR detectors, respectively, at room temperature.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/6/e1700589/DC1

    fig. S1. Raman spectra of b-AsP with different thicknesses.

    fig. S2. The transfer curves of two typical b-AsP FET devices.

    fig. S3. The photocurrent mappings of a typical device at near-IR range.

    fig. S4. The performance of a typical b-AsP device at visible- and near-IR range.

    fig. S5. Fast photoresponse at near-IR.

    fig. S6. Laser polarization direction–sensitive photocurrent mapping.

    fig. S7. Photocurrent mapping of the b-As0.83P0.17/MoS2 heterostructure.

    fig. S8. Photoresponsivity and EQE of a typical b-As0.83P0.17/MoS2 heterostructure device.

    fig. S9. The stability of b-AsP samples spin-coated by a PMMA layer.

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. Raman spectra of b-AsP with different thicknesses.
    • fig. S2. The transfer curves of two typical b-AsP FET devices.
    • fig. S3. The photocurrent mappings of a typical device at near-IR range.
    • fig. S4. The performance of a typical b-AsP device at visible- and near-IR range.
    • fig. S5. Fast photoresponse at near-IR.
    • fig. S6. Laser polarization direction–sensitive photocurrent mapping.
    • fig. S7. Photocurrent mapping of the b-As0.83P0.17/MoS2 heterostructure.
    • fig. S8. Photoresponsivity and EQE of a typical b-As0.83P0.17/MoS2 heterostructure device.
    • fig. S9. The stability of b-AsP samples spin-coated by a PMMA layer.

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