%AHuang, Wei%AChien, Po-Hsiu%AMcMillen, Kyle%APatel, Sawankumar%ATedesco, Joshua%AZeng, Li%AMukherjee, Subhrangsu%AWang, Binghao%AChen, Yao%AWang, Gang%AWang, Yang%AGao, Yanshan%ABedzyk, Michael%ADeLongchamp, Dean%AHu, Yan-Yan%AMedvedeva, Julia%AMarks, Tobin%AFacchetti, Antonio%BJournal Name: Proceedings of the National Academy of Sciences; Journal Volume: 117; Journal Issue: 31; Related Information: CHORUS Timestamp: 2020-08-05 14:38:27 %D2020%IProceedings of the National Academy of Sciences %JJournal Name: Proceedings of the National Academy of Sciences; Journal Volume: 117; Journal Issue: 31; Related Information: CHORUS Timestamp: 2020-08-05 14:38:27 %K %MOSTI ID: 10174973 %PMedium: X %TExperimental and theoretical evidence for hydrogen doping in polymer solution-processed indium gallium oxide %X

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-state1H,71Ga, and115In NMR spectroscopy; and discrete Fourier transform (DFT) analysis with ab initio molecular dynamics (MD) liquid-quench simulations. The71Ga{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.

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