Inverse spinel Zn2SnO4 (ZTO) films have been grown on MgO(001) and MgAl2O4(001) substrates by pulsed laser deposition. Detailed structural investigation by high-resolution X-ray diffraction, including conventional θ–2θ linear scans, φ scans and reciprocal space mappings, revealed the epitaxial characteristics of the ZTO films. Meanwhile, the in-plane and out-of-plane lattice parameters were extracted to be about a = b=8.615 A and c = 8.629 A from the symmetry and asymmetry reflections. The surface morphologies of ZTO films were examined by atomic force microscopy, and all the films exhibit very smooth surfaces. X-ray photoelectron spectroscopy measurement was taken to disclose the oxidation states of elements. The optical properties of ZTO films were probed by measuring the optical transmittances. The band gaps of ZTO films grown on MgO(001) and MgAl2O4(001) were extracted to be 4.26 eV and 4.30 eV by extrapolating the absorption edge, respectively. Theoretically, the band structure was also calculated using density functional theory. The results show that ZTO film is a direct band gap semiconductor with the band gap value of 2.64 eV. Such a wide band gap semiconductor with an inverse spinel structure should be of high interest for epitaxial heterojunction and optical device application.

中文翻译：

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反尖晶石Zn2SnO4外延膜的结构和光学带隙

通过脉冲激光沉积在 MgO(001) 和 MgAl2O4(001) 衬底上生长了反尖晶石 Zn2SnO4 (ZTO) 薄膜。通过高分辨率 X 射线衍射进行详细的结构研究，包括传统的 θ–2θ 线性扫描、φ 扫描和倒易空间映射，揭示了 ZTO 薄膜的外延特性。同时，从对称和不对称反射中提取的面内和面外晶格参数约为 a = b=8.615 A 和 c = 8.629 A。通过原子力显微镜检查 ZTO 薄膜的表面形貌，所有薄膜都表现出非常光滑的表面。进行 X 射线光电子能谱测量以揭示元素的氧化态。通过测量光学透射率来探测 ZTO 薄膜的光学性能。通过外推吸收边，在 MgO(001) 和 MgAl2O4(001) 上生长的 ZTO 薄膜的带隙分别提取为 4.26 eV 和 4.30 eV。理论上，能带结构也是使用密度泛函理论计算的。结果表明，ZTO薄膜是直接带隙半导体，带隙值为2.64 eV。这种具有反尖晶石结构的宽带隙半导体对于外延异质结和光学器件应用应该是非常重要的。