Experimental and theoretical evidence for hydrogen doping in polymer solution-processed indium gallium oxide

Wei Huang, Po Hsiu Chien, Kyle McMillen, Sawankumar Patel, Joshua Tedesco, Li Zeng, Subhrangsu Mukherjee, Binghao Wang, Yao Chen, Gang Wang, Yang Wang, Yanshan Gao, Michael J. Bedzyk, Dean M. Delongchamp, Yan Yan Hu, Julia E. Medvedeva, Tobin J. Marks, Antonio Facchetti

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

The field-effect electron mobility of aqueous solution-processed indium gallium oxide (IGO) thin-film transistors (TFTs) is significantly enhanced by polyvinyl alcohol (PVA) addition to the precursor solution, a >70-fold increase to 7.9 cm2/Vs. To understand the origin of this remarkable phenomenon, microstructure, electronic structure, and charge transport of IGO:PVA film are investigated by a battery of experimental and theoretical techniques, including In K-edge and Ga K-edge extended X-ray absorption fine structure (EXAFS); resonant soft X-ray scattering (R-SoXS); ultraviolet photoelectron spectroscopy (UPS); Fourier transform-infrared (FT-IR) spectroscopy; time-of-flight secondary-ion mass spectrometry (ToF-SIMS); composition-/processing-dependent TFT properties; high-resolution solid-state 1H, 71Ga, and 115In NMR spectroscopy; and discrete Fourier transform (DFT) analysis with ab initio molecular dynamics (MD) liquid-quench simulations. The 71Ga{1H} rotational-echo double-resonance (REDOR) NMR and other data indicate that PVA achieves optimal H doping with a Ga···H distance of ∼3.4 Å and conversion from six-to four-coordinate Ga, which together suppress deep trap defect localization. This reduces metal-oxide polyhedral distortion, thereby increasing the electron mobility. Hydroxyl polymer doping thus offers a pathway for efficient H doping in green solvent-processed metal oxide films and the promise of high-performance, ultra-stable metal oxide semiconductor electronics with simple binary compositions.

Original languageEnglish (US)
Pages (from-to)18231-18239
Number of pages9
JournalProceedings of the National Academy of Sciences of the United States of America
Volume117
Issue number31
DOIs
StatePublished - Aug 4 2020

Funding

ACKNOWLEDGMENTS. Thin-film oxide-polymer transistor fabrication, evaluation, and spectroscopy were supported by Air Force Office of Scientific Research Grant FA9550-18-1-0320 (to Y.C., G.W., and A.F.); the Northwestern University NSF Materials Research Science and Engineering Centers (MRSEC) Grant DMR-1720139 (to W.H., J.T., and L.Z.); US Department of Commerce, National Institute of Standards and Technology as part of the Center for Hierarchical Materials Design Award 70NANB19H005; and Flexterra Corp (A.F.). SS-NMR was supported by the Northwestern University NSF MRSEC Grant DMR-1720139 (to P.-H.C., S.P., and Y.-Y.H.). This work made use of the J. B. Cohen X-Ray Diffraction Facility, Northwestern University Micro/Nano Fabrication Facility, Electron Probe Instrumentation Center facility, Keck-II facility, and Scanned Probe Imaging and Develoment facility of the North-western University Atomic and Nanoscale Characterization Experimental Center at Northwestern University, which is partially supported by NSF Soft and Hybrid Nanotechnology Experimental Resource Grant ECCS-1542205, NSF MRSEC Grant DMR-1720139, the State of Illinois, and Northwestern University. All solid-sate NMR experiments were performed at the National High Magnetic Field Laboratory. The National High Magnetic Field Laboratory is supported by NSF Grant NSF/DMR-1644779 and the State of Florida. K.M. and J.E.M. were supported by NSF Designing Materials to Revolutionize and Engineer our Future Grant DMR-1729779 for MD simulations and DFT calculations; computational resources were provided by the NSF-supported Extreme Science and Engineering Discovery Environment program and by Department of Energy (DOE) National Energy Research Scientific Computing Center facilities. R-SoXS data were acquired at Beamline 11.0.1.2 of the Advanced Light Source (ALS), which is a DOE Office of Science User Facility under Contract DE-AC02-05CH11231. We thank C. Wang (ALS) for assisting with the R-SoXS experiment setup and providing instrument maintenance.

Keywords

  • Hydrogen doping
  • Indium gallium oxide
  • Oxide semiconductor
  • Polymer incorporation
  • Transistor

ASJC Scopus subject areas

  • General

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