Research ArticleMATERIALS SCIENCE

High-performance and scalable metal-chalcogenide semiconductors and devices via chalco-gel routes

See allHide authors and affiliations

Science Advances  13 Apr 2018:
Vol. 4, no. 4, eaap9104
DOI: 10.1126/sciadv.aap9104
  • Fig. 1 Synthetic procedure for metal-chalcogenide precursor solutions and thin films.

    (A) Schematic illustration describing the chalco-gel–based synthesis of a CdSe precursor solution and thin-film formation. (B) NMR chemical shifts of 113Cd compounds. (C) Photographic images of a series of metal (M = Cd, Pb, Zn, In, Sb)–chalcogenide (Q = S, Se, Te) solutions. (D) TGA of CdS, CdSe, CdTe, In2S3, ZnS, ZnSe, PbS, PbSe, and PbTe precursor solutions.

  • Fig. 2 Characterization of metal-chalcogenide thin films.

    (A) TEM cross-sectional image of a CdSe thin film on an Al2O3 gate dielectric (inset: the electron diffraction pattern obtained by FFT). (B) Measured (black line) and reference (red line) XRD peaks of metal-chalcogenide thin films: CdS, CdSe, CdTe, Sb2S3, Sb2Se3, PbS, PbSe, In2S3, In2Se3, ZnS, and ZnSe. (C) Secondary ion mass spectroscopy (SIMS) of a CdSe thin film on Si wafer. (D) Tauc plots for CdSemTe1−m, CdSmSe1−m, and CdmZn1−mS (m = 0, 0.5, and 1, respectively) alloy films fabricated on glass substrates. (E) Optical absorbance spectra of CdZnSeS alloy thin films on glass substrates. Indicated R, G, and B color bars show laser source wavelengths of 406 nm (blue), 520 nm (green), and 638 nm (red), respectively.

  • Fig. 3 Electrical characteristics of solution-processed metal-chalcogenide TFTs.

    Transfer and output characteristics of (A) CdSe TFTs using silicon dioxide gate dielectrics (W/L = 1000 μm/100 μm). (B) Saturation and linear mobility statistics of CdSe TFTs on silicon dioxide gate dielectrics. (C) CdSe, CdS, and In2Se3 TFTs (W/L = 200 μm/20 μm) using ALD-deposited Al2O3 gate dielectrics. (D) Temperature dependence of field-effect mobility for an n-channel CdSe TFT device fabricated on a SiO2 gate dielectric.

  • Fig. 4 Large-area solution-processed CdSe TFT arrays on a Si wafer and on glass substrates.

    (A) Photograph, optical microscope images, and schematics of CdSe TFTs fabricated on 2.5-inch glass substrates and a 4-inch Si wafer. (B) A series of TFT transfer characteristics on a glass substrate measured at each numbered segment (W/L = 200 μm/20 μm). (C) Transfer curves, photosensitivity, and dynamic ranges of CdSe phototransistors under pulsed-laser wavelengths of 406 nm (blue), 520 nm (green), and 638 nm (red). (D) Oscillation frequency and propagation delay per stage as a function of supply bias (VDD) for a seven-stage CdSe ring oscillator circuit. (E) Threshold voltage shift (ΔVT) of CdSe TFTs under positive gate bias stress measured in air and N2 ambient.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/4/eaap9104/DC1

    fig. S1. 1H NMR for coordination of acetylacetone on a cadmium precursor.

    fig. S2. The photograph of vacuum-dried DMSO-based CdS and CdSe precursor solutions.

    fig. S3. Metal-chalcogenide surface images were obtained by AFM.

    fig. S4. Metal-chalcogenide surface images were obtained by FE-SEM.

    fig. S5. Metal-chalcogenide surface images were obtained by an optical microscope.

    fig. S6. Cross-sectional HRTEM image and diffraction pattern of the CdSe TFT.

    fig. S7. RBS and XPS analysis of the CdSe films.

    fig. S8. Transmittance of the metal-chalcogenide alloy films.

    fig. S9. Characterization of the CdSe TFTs on the SiO2 substrate.

    fig. S10. Grazing incident XRD peaks of 20-nm-thick CdSe films made with different types of solvent.

    fig. S11. XRD peaks of the CdSe layer with precursor concentrations.

    fig. S12. SIMS data of the CdSe layer with precursor concentrations.

    fig. S13. Electrical mobility properties of the CdSe TFTs with precursor concentrations.

    fig. S14. FE-SEM image of the CdSe films.

    fig. S15. Characterization of the gate dielectric layer.

    fig. S16. Characterization of the CdSe TFTs on Al2O3 dielectric.

    fig. S17. Temperature dependence of field-effect mobility for an n-channel CdSe TFTs.

    fig. S18. Electrical characteristics of the CdSe TFTs with different channel lengths (5, 10, 20, and 50 μm).

    fig. S19. Characterization of the CdSe phototransistor.

    fig. S20. Characterization of the Cd1−xZnxSe1−ySy phototransistors.

    fig. S21. Characterization of the CdSe circuits.

    fig. S22. Positive bias stress test of the CdSe TFTs.

    table S1. Solution stability relation of the metal-chalcogenide precursor with the complexing agent.

    table S2. Synthetic information of the metal-chalcogenide solutions.

    table S3. Diffraction pattern distance, d-spacing, and Miller indices of the CdSe thin film.

    table S4. Average saturation mobility of CdSe TFTs with different types of solvent.

    References (5658)

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. 1H NMR for coordination of acetylacetone on a cadmium precursor.
    • fig. S2. The photograph of vacuum-dried DMSO-based CdS and CdSe precursor solutions.
    • fig. S3. Metal-chalcogenide surface images were obtained by AFM.
    • fig. S4. Metal-chalcogenide surface images were obtained by FE-SEM.
    • fig. S5. Metal-chalcogenide surface images were obtained by an optical microscope.
    • fig. S6. Cross-sectional HRTEM image and diffraction pattern of the CdSe TFT.
    • fig. S7. RBS and XPS analysis of the CdSe films.
    • fig. S8. Transmittance of the metal-chalcogenide alloy films.
    • fig. S9. Characterization of the CdSe TFTs on the SiO2 substrate.
    • fig. S10. Grazing incident XRD peaks of 20-nm-thick CdSe films made with different types of solvent.
    • fig. S11. XRD peaks of the CdSe layer with precursor concentrations.
    • fig. S12. SIMS data of the CdSe layer with precursor concentrations.
    • fig. S13. Electrical mobility properties of the CdSe TFTs with precursor concentrations.
    • fig. S14. FE-SEM image of the CdSe films.
    • fig. S15. Characterization of the gate dielectric layer.
    • fig. S16. Characterization of the CdSe TFTs on Al2O3 dielectric.
    • fig. S17. Temperature dependence of field-effect mobility for an n-channel CdSe TFTs.
    • fig. S18. Electrical characteristics of the CdSe TFTs with different channel lengths (5, 10, 20, and 50 μm).
    • fig. S19. Characterization of the CdSe phototransistor.
    • fig. S20. Characterization of the Cd1−xZnxSe1−ySy phototransistors.
    • fig. S21. Characterization of the CdSe circuits.
    • fig. S22. Positive bias stress test of the CdSe TFTs.
    • table S1. Solution stability relation of the metal-chalcogenide precursor with the complexing agent.
    • table S2. Synthetic information of the metal-chalcogenide solutions.
    • table S3. Diffraction pattern distance, d-spacing, and Miller indices of the CdSe thin film.
    • table S4. Average saturation mobility of CdSe TFTs with different types of solvent.
    • References (56–58)

    Download PDF

    Files in this Data Supplement: