Same Precursor, Two Different Products: Comparing the Structural Evolution of In–Ga–O “Gel-Derived” Powders and Solution-Cast Films Using Pair Distribution Function Analysis
Same Precursor, Two Different Products: Comparing the Structural Evolution of In–Ga–O “Gel-Derived” Powders and Solution-Cast Films Using Pair Distribution Function Analysis
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相同的前驱体，两种不同的产品：使用配对分布函数分析比较 In-Ga-O-凝胶衍生粉末和溶液流延薄膜的结构演变
DOI：
10.1021/jacs.7b02097
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发表时间：
2017
影响因子：
15
通讯作者：
Johnson, David C.
中科院分区：
文献类型：
--
作者：
Wood, Suzannah R.;Woods, Keenan N.;Plassmeyer, Paul N.;Marsh, David A.;Johnson, Darren W.;Page, Catherine J.;Jensen, Kirsten M.;Johnson, David C.
无定形金属氧化物是各种技术应用的核心。特别地，氧化铟镓作为薄膜晶体管沟道层材料已经引起关注。在这项工作中，我们研究了铟镓氧化物凝胶衍生的粉末和薄膜的结构演变，使用红外振动光谱，X射线衍射和对分布函数（PDF）分析的X射线总散射从标准和垂直入射薄膜几何形状（tfPDF）。我们发现，由相同水溶液前驱体制备的凝胶粉末和薄膜随温度的变化不同，形成了不同取代度的Ga取代In 2 O3和In取代β-Ga 2 O3的混合物。X射线全散射和PDF分析表明，粉末和薄膜的主要相是非晶/纳米晶β-Ga 2 O3相，具有明显较大的相干长度的In 2 O3的次要成分。这种非晶β-Ga 2 O3相不能用传统的布拉格衍射技术来研究晶体金属氧化物薄膜。布拉格衍射和tfPDF的结合提供了一个更完整的描述薄膜的组成和结构，它可以用来详细的工艺条件和结构-性能关系的影响。这项研究还演示了如何使用tfPDF来阐明传统上难以通过标准衍射表征的非晶材料的结构特征。
Amorphous metal oxides are central to a variety of technological applications. In particular, indium gallium oxide has garnered attention as a thin-film transistor channel layer material. In this work we examine the structural evolution of indium gallium oxide gel-derived powders and thin films using infrared vibrational spectroscopy, X-ray diffraction, and pair distribution function (PDF) analysis of X-ray total scattering from standard and normal incidence thin-film geometries (tfPDF). We find that the gel-derived powders and films from the same aqueous precursor evolve differently with temperature, forming mixtures of Ga-substituted In2O3and In-substituted β-Ga2O3with different degrees of substitution. X-ray total scattering and PDF analysis indicate that the majority phase for both the powders and films is an amorphous/nanocrystalline β-Ga2O3phase, with a minor constituent of In2O3with significantly larger coherence lengths. This amorphous β-Ga2O3phase could not be identified using the conventional Bragg diffraction techniques traditionally used to study crystalline metal oxide thin films. The combination of Bragg diffraction and tfPDF provides a much more complete description of film composition and structure, which can be used to detail the effect of processing conditions and structure–property relationships. This study also demonstrates how structural features of amorphous materials, traditionally difficult to characterize by standard diffraction, can be elucidated using tfPDF.