@article{031ad79014bc42ffb7ab05029f7e7c5f,
title = "Disorders and oxygen vacancies in p-type Sn2B2O7 (B = Nb, Ta): Role of the B-site element",
abstract = "Sn2Nb2−xTaxO7 (x = 0.0–2.0) with pyrochlore structure is a promising material for p-type oxide semiconductors. A systematic study of its Nb/Ta ratio indicated that the hole–generation efficiency of the Nb end (Sn2Nb2O7) was an order of magnitude lower than that of the Ta end (Sn2Ta2O7). Although this occurs due to differences in oxygen-vacancy formation, the origins of the hole–generation efficiencies remain unclear due to limited information on local and global crystal-structure disorders in pyrochlore Sn2Nb2O7 and Sn2Ta2O7. In this study, the crystal structures of Sn2B2O7 (B = Nb, Ta), composed of BO6 octahedra and Sn4O tetrahedra, were investigated using X-ray absorption spectroscopy and X-ray diffraction. A detailed investigation of the local and global crystal structures indicated a larger amount of disorder in the Sn4O tetrahedra in Sn2Nb2O7 compared to Sn2Ta2O7; disorder in the BO6 octahedra occurred only in Sn2Ta2O7. This study indicates that an appropriate selection of the B-site element is vital for suppressing defect and disorder formation in Sn4O tetrahedra and subsequently improving the hole–carrier–generation efficiency.",
keywords = "X-ray methods, defects, oxides, pyrochlore, semiconductors",
author = "Akane Samizo and Makoto Minohara and Naoto Kikuchi and Kenta Ando and Yuta Mazuka and Keishi Nishio",
note = "Funding Information: This work was supported by a Grant-in-Aid for Scientific Research (Grant Numbers 20K22472 and 22K05277) from the Japan Society for the Promotion of Science (JSPS) and a Tokyo University of Science (TUS) Grant for Young and Female Researchers. The work at KEK-PF was performed with the approval of the Program Advisory Committee (Proposals Numbers 2019G543 and 2020G657) at the Institute of Materials Structure Science, KEK. We are grateful to Dr. Hiroaki Nitani for his technical support with EXAFS measurements. We would like to thank Editage (www.editage.com) for English language editing. Funding Information: This work was supported by a Grant‐in‐Aid for Scientific Research (Grant Numbers 20K22472 and 22K05277) from the Japan Society for the Promotion of Science (JSPS) and a Tokyo University of Science (TUS) Grant for Young and Female Researchers. The work at KEK‐PF was performed with the approval of the Program Advisory Committee (Proposals Numbers 2019G543 and 2020G657) at the Institute of Materials Structure Science, KEK. We are grateful to Dr. Hiroaki Nitani for his technical support with EXAFS measurements. We would like to thank Editage ( www.editage.com ) for English language editing. Publisher Copyright: {\textcopyright} 2022 The American Ceramic Society.",
year = "2022",
doi = "10.1111/jace.18830",
language = "English",
volume = "106",
pages = "1540--1546",
journal = "Journal of the American Ceramic Society",
issn = "0002-7820",
publisher = "Wiley-Blackwell",
number = "2",
}