| Autor: |
Wood SR; Department of Chemistry and Biochemistry, and Material Science Institute, University of Oregon , Eugene, Oregon 97403, United States., Woods KN; Department of Chemistry and Biochemistry, and Material Science Institute, University of Oregon , Eugene, Oregon 97403, United States., Plassmeyer PN; Department of Chemistry and Biochemistry, and Material Science Institute, University of Oregon , Eugene, Oregon 97403, United States., Marsh DA; Department of Chemistry and Biochemistry, and Material Science Institute, University of Oregon , Eugene, Oregon 97403, United States., Johnson DW; Department of Chemistry and Biochemistry, and Material Science Institute, University of Oregon , Eugene, Oregon 97403, United States., Page CJ; Department of Chemistry and Biochemistry, and Material Science Institute, University of Oregon , Eugene, Oregon 97403, United States., Jensen KMØ; Department of Chemistry, University of Copenhagen , 2100 Copenhagen, Denmark., Johnson DC; Department of Chemistry and Biochemistry, and Material Science Institute, University of Oregon , Eugene, Oregon 97403, United States. |
| Abstrakt: |
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 In 2 O 3 and In-substituted β-Ga 2 O 3 with 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-Ga 2 O 3 phase, with a minor constituent of In 2 O 3 with significantly larger coherence lengths. This amorphous β-Ga 2 O 3 phase 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. |
