Electronic Structure and Defect Chemistry of Tin(II) Complex Oxide SnNb2O6
Electronic Structure and Defect Chemistry of Tin(II) Complex Oxide SnNb2O6
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锡(II)复合氧化物SnNb2O6的电子结构和缺陷化学
DOI：
10.1021/acs.jpcc.6b01696
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发表时间：
2016
影响因子：
3.7
通讯作者：
F. Oba and I. Tanaka
中科院分区：
文献类型：
--
作者：
S. Katayama;H. Hayashi;Y. Kumagai;F. Oba and I. Tanaka
由于Sn5sp轨道的贡献，锡(II)复合氧化物具有独特的价带结构。通过第一性原理计算和外延薄膜的表征，研究了TiN(II)Nb2O6(SnNb2O6)的基本电学、光学和缺陷性质。计算揭示了其与SnO相似的特征价带结构。SnNb2O6具有间接能带结构，间接能隙为2.41 eV，直接能隙为2.55 eV。采用脉冲激光沉积技术在Al_2O_3(011̅_2)衬底上制备了表面光滑的SnNb_2O_6外延薄膜。实验和理论吸收光谱一致表明，吸收阈值为∼2.5 eV。采用固相反应法制备的未掺杂薄膜和掺杂烧结样品均表现出较高的电阻率。理论缺陷能量学表明，高的电阻率是由于氧空位和TiN-on-Nb反位的电荷补偿所致。
Tin(II) complex oxides have unique valence band structures due to the contribution of the Sn 5sp orbitals. We investigate the fundamental electronic, optical, and defect properties of tin(II) niobate (SnNb2O6) via first-principles calculations and the characterization of epitaxial thin films. The calculations reveal its characteristic valence band structure similar to that of SnO. SnNb2O6is predicted to have an indirect-type band structure with an indirect gap of 2.41 eV and a direct gap of 2.55 eV. Epitaxial thin films of SnNb2O6with smooth surfaces are fabricated on Al2O3(011̅2) substrates using pulsed laser deposition. Experimental and theoretical absorption spectra consistently show an absorption threshold of ∼2.5 eV. Both undoped thin films and doped sintered samples fabricated by a solid-state reaction show high electrical resistivities. Theoretical defect energetics suggests that the high resistivity is due to the charge compensation by oxygen vacancies and tin-on-niobium antisites.