Experimental and theoretical evidence for hydrogen doping in polymer solution-processed indium gallium oxide
Experimental and theoretical evidence for hydrogen doping in polymer solution-processed indium gallium oxide
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DOI：
10.1073/pnas.2007897117
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发表时间：
2020-08-04
影响因子：
11.1
通讯作者：
Facchetti, Antonio
中科院分区：
文献类型：
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作者：
Huang, Wei;Chien, Po-Hsiu;Facchetti, Antonio
通过向前驱体溶液中添加聚乙烯醇（PVA），水溶液处理的氧化铟镓（IGO）薄膜晶体管（TFT）的场效应电子迁移率显著提高，提高了70多倍，达到7.9 cm²/Vs。为了理解这一显著现象的成因，通过一系列实验和理论技术对IGO:PVA薄膜的微观结构、电子结构和电荷传输进行了研究，这些技术包括铟K边和镓K边扩展X射线吸收精细结构（EXAFS）；共振软X射线散射（R - SoXS）；紫外光电子能谱（UPS）；傅里叶变换红外（FT - IR）光谱；飞行时间二次离子质谱（ToF - SIMS）；与成分/工艺相关的TFT特性；高分辨率固态H - 1、Ga - 71和In - 115核磁共振（NMR）光谱；以及采用从头算分子动力学（MD）液体淬火模拟的离散傅里叶变换（DFT）分析。Ga - 71{H - 1}旋转回波双共振（REDOR）NMR和其他数据表明，PVA实现了最佳的氢掺杂，镓···氢距离约为3.4埃，并使镓从六配位转变为四配位，这两者共同抑制了深陷阱缺陷的局域化。这减少了金属氧化物多面体的畸变，从而提高了电子迁移率。因此，羟基聚合物掺杂为在绿色溶剂处理的金属氧化物薄膜中进行高效氢掺杂提供了一种途径，并为具有简单二元成分的高性能、超稳定金属氧化物半导体电子器件带来了希望。
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 cm(2)/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 H-1, Ga-71, and In-115 NMR spectroscopy; and discrete Fourier transform (DFT) analysis with ab initio molecular dynamics (MD) liquid-quench simulations. The Ga-71{H-1} rotational-echo double-resonance (REDOR) NMR and other data indicate that PVA achieves optimal H doping with a Ga center dot center dot center dot H distance of similar to 3.4 angstrom 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.