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

31 Scopus citations


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
Issue number31
StatePublished - Aug 4 2020


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

ASJC Scopus subject areas

  • General


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