TY - JOUR
T1 - Experimental and theoretical evidence for hydrogen doping in polymer solution-processed indium gallium oxide
AU - Huang, Wei
AU - Chien, Po Hsiu
AU - McMillen, Kyle
AU - Patel, Sawankumar
AU - Tedesco, Joshua
AU - Zeng, Li
AU - Mukherjee, Subhrangsu
AU - Wang, Binghao
AU - Chen, Yao
AU - Wang, Gang
AU - Wang, Yang
AU - Gao, Yanshan
AU - Bedzyk, Michael J.
AU - Delongchamp, Dean M.
AU - Hu, Yan Yan
AU - Medvedeva, Julia E.
AU - Marks, Tobin J.
AU - Facchetti, Antonio
N1 - Funding Information:
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.
Publisher Copyright:
© 2020 National Academy of Sciences. All rights reserved.
PY - 2020/8/4
Y1 - 2020/8/4
N2 - 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.
AB - 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.
KW - Hydrogen doping
KW - Indium gallium oxide
KW - Oxide semiconductor
KW - Polymer incorporation
KW - Transistor
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U2 - 10.1073/pnas.2007897117
DO - 10.1073/pnas.2007897117
M3 - Article
C2 - 32703807
AN - SCOPUS:85089162795
VL - 117
SP - 18231
EP - 18239
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 31
ER -